This is doc/gfortran.info, produced by makeinfo version 4.11 from /gcc-4.3/gcc-4.3.1/gcc-4.3.1/gcc/fortran/gfortran.texi. Copyright (C) 1999-2007 Free Software Foundation, Inc. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.1 or any later version published by the Free Software Foundation; with the Invariant Sections being "GNU General Public License" and "Funding Free Software", the Front-Cover texts being (a) (see below), and with the Back-Cover Texts being (b) (see below). A copy of the license is included in the section entitled "GNU Free Documentation License". (a) The FSF's Front-Cover Text is: A GNU Manual (b) The FSF's Back-Cover Text is: You have freedom to copy and modify this GNU Manual, like GNU software. Copies published by the Free Software Foundation raise funds for GNU development. INFO-DIR-SECTION Software development START-INFO-DIR-ENTRY * gfortran: (gfortran). The GNU Fortran Compiler. END-INFO-DIR-ENTRY This file documents the use and the internals of the GNU Fortran compiler, (`gfortran'). Published by the Free Software Foundation 51 Franklin Street, Fifth Floor Boston, MA 02110-1301 USA Copyright (C) 1999-2007 Free Software Foundation, Inc. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.1 or any later version published by the Free Software Foundation; with the Invariant Sections being "GNU General Public License" and "Funding Free Software", the Front-Cover texts being (a) (see below), and with the Back-Cover Texts being (b) (see below). A copy of the license is included in the section entitled "GNU Free Documentation License". (a) The FSF's Front-Cover Text is: A GNU Manual (b) The FSF's Back-Cover Text is: You have freedom to copy and modify this GNU Manual, like GNU software. Copies published by the Free Software Foundation raise funds for GNU development.  File: gfortran.info, Node: Top, Next: Introduction, Up: (dir) Introduction ************ This manual documents the use of `gfortran', the GNU Fortran compiler. You can find in this manual how to invoke `gfortran', as well as its features and incompatibilities. * Menu: * Introduction:: Part I: Invoking GNU Fortran * Invoking GNU Fortran:: Command options supported by `gfortran'. * Runtime:: Influencing runtime behavior with environment variables. Part II: Language Reference * Fortran 2003 status:: Fortran 2003 features supported by GNU Fortran. * Extensions:: Language extensions implemented by GNU Fortran. * Intrinsic Procedures:: Intrinsic procedures supported by GNU Fortran. * Intrinsic Modules:: Intrinsic modules supported by GNU Fortran. * Contributing:: How you can help. * Copying:: GNU General Public License says how you can copy and share GNU Fortran. * GNU Free Documentation License:: How you can copy and share this manual. * Funding:: How to help assure continued work for free software. * Option Index:: Index of command line options * Keyword Index:: Index of concepts  File: gfortran.info, Node: Introduction, Next: Invoking GNU Fortran, Prev: Top, Up: Top 1 Introduction ************** The GNU Fortran compiler front end was designed initially as a free replacement for, or alternative to, the unix `f95' command; `gfortran' is the command you'll use to invoke the compiler. * Menu: * About GNU Fortran:: What you should know about the GNU Fortran compiler. * GNU Fortran and GCC:: You can compile Fortran, C, or other programs. * Preprocessing and conditional compilation:: The Fortran preprocessor * GNU Fortran and G77:: Why we chose to start from scratch. * Project Status:: Status of GNU Fortran, roadmap, proposed extensions. * Standards:: Standards supported by GNU Fortran.  File: gfortran.info, Node: About GNU Fortran, Next: GNU Fortran and GCC, Up: Introduction 1.1 About GNU Fortran ===================== The GNU Fortran compiler is still in an early state of development. It can generate code for most constructs and expressions, but much work remains to be done. When the GNU Fortran compiler is finished, it will do everything you expect from any decent compiler: * Read a user's program, stored in a file and containing instructions written in Fortran 77, Fortran 90, Fortran 95 or Fortran 2003. This file contains "source code". * Translate the user's program into instructions a computer can carry out more quickly than it takes to translate the instructions in the first place. The result after compilation of a program is "machine code", code designed to be efficiently translated and processed by a machine such as your computer. Humans usually aren't as good writing machine code as they are at writing Fortran (or C++, Ada, or Java), because is easy to make tiny mistakes writing machine code. * Provide the user with information about the reasons why the compiler is unable to create a binary from the source code. Usually this will be the case if the source code is flawed. When writing Fortran, it is easy to make big mistakes. The Fortran 90 requires that the compiler can point out mistakes to the user. An incorrect usage of the language causes an "error message". The compiler will also attempt to diagnose cases where the user's program contains a correct usage of the language, but instructs the computer to do something questionable. This kind of diagnostics message is called a "warning message". * Provide optional information about the translation passes from the source code to machine code. This can help a user of the compiler to find the cause of certain bugs which may not be obvious in the source code, but may be more easily found at a lower level compiler output. It also helps developers to find bugs in the compiler itself. * Provide information in the generated machine code that can make it easier to find bugs in the program (using a debugging tool, called a "debugger", such as the GNU Debugger `gdb'). * Locate and gather machine code already generated to perform actions requested by statements in the user's program. This machine code is organized into "modules" and is located and "linked" to the user program. The GNU Fortran compiler consists of several components: * A version of the `gcc' command (which also might be installed as the system's `cc' command) that also understands and accepts Fortran source code. The `gcc' command is the "driver" program for all the languages in the GNU Compiler Collection (GCC); With `gcc', you can compile the source code of any language for which a front end is available in GCC. * The `gfortran' command itself, which also might be installed as the system's `f95' command. `gfortran' is just another driver program, but specifically for the Fortran compiler only. The difference with `gcc' is that `gfortran' will automatically link the correct libraries to your program. * A collection of run-time libraries. These libraries contain the machine code needed to support capabilities of the Fortran language that are not directly provided by the machine code generated by the `gfortran' compilation phase, such as intrinsic functions and subroutines, and routines for interaction with files and the operating system. * The Fortran compiler itself, (`f951'). This is the GNU Fortran parser and code generator, linked to and interfaced with the GCC backend library. `f951' "translates" the source code to assembler code. You would typically not use this program directly; instead, the `gcc' or `gfortran' driver programs will call it for you.  File: gfortran.info, Node: GNU Fortran and GCC, Next: Preprocessing and conditional compilation, Prev: About GNU Fortran, Up: Introduction 1.2 GNU Fortran and GCC ======================= GNU Fortran is a part of GCC, the "GNU Compiler Collection". GCC consists of a collection of front ends for various languages, which translate the source code into a language-independent form called "GENERIC". This is then processed by a common middle end which provides optimization, and then passed to one of a collection of back ends which generate code for different computer architectures and operating systems. Functionally, this is implemented with a driver program (`gcc') which provides the command-line interface for the compiler. It calls the relevant compiler front-end program (e.g., `f951' for Fortran) for each file in the source code, and then calls the assembler and linker as appropriate to produce the compiled output. In a copy of GCC which has been compiled with Fortran language support enabled, `gcc' will recognize files with `.f', `.for', `.ftn', `.f90', `.f95', and `.f03' extensions as Fortran source code, and compile it accordingly. A `gfortran' driver program is also provided, which is identical to `gcc' except that it automatically links the Fortran runtime libraries into the compiled program. Source files with `.f', `.for', `.fpp', `.ftn', `.F', `.FOR', `.FPP', and `.FTN' extensions are treated as fixed form. Source files with `.f90', `.f95', `.f03', `.F90', `.F95', and `.F03' extensions are treated as free form. The capitalized versions of either form are run through preprocessing. Source files with the lower case `.fpp' extension are also run through preprocessing. This manual specifically documents the Fortran front end, which handles the programming language's syntax and semantics. The aspects of GCC which relate to the optimization passes and the back-end code generation are documented in the GCC manual; see *note Introduction: (gcc)Top. The two manuals together provide a complete reference for the GNU Fortran compiler.  File: gfortran.info, Node: Preprocessing and conditional compilation, Next: GNU Fortran and G77, Prev: GNU Fortran and GCC, Up: Introduction 1.3 Preprocessing and conditional compilation ============================================= Many Fortran compilers including GNU Fortran allow passing the source code through a C preprocessor (CPP; sometimes also called the Fortran preprocessor, FPP) to allow for conditional compilation. In the case of GNU Fortran, this is the GNU C Preprocessor in the traditional mode. On systems with case-preserving file names, the preprocessor is automatically invoked if the file extension is `.F', `.FOR', `.FTN', `.F90', `.F95' or `.F03'; otherwise use for fixed-format code the option `-x f77-cpp-input' and for free-format code `-x f95-cpp-input'. Invocation of the preprocessor can be suppressed using `-x f77' or `-x f95'. If the GNU Fortran invoked the preprocessor, `__GFORTRAN__' is defined and `__GNUC__', `__GNUC_MINOR__' and `__GNUC_PATCHLEVEL__' can be used to determine the version of the compiler. See *note Overview: (cpp)Top. for details. While CPP is the de-facto standard for preprocessing Fortran code, Part 3 of the Fortran 95 standard (ISO/IEC 1539-3:1998) defines Conditional Compilation, which is not widely used and not directly supported by the GNU Fortran compiler. You can use the program coco to preprocess such files (`http://users.erols.com/dnagle/coco.html').  File: gfortran.info, Node: GNU Fortran and G77, Next: Project Status, Prev: Preprocessing and conditional compilation, Up: Introduction 1.4 GNU Fortran and G77 ======================= The GNU Fortran compiler is the successor to `g77', the Fortran 77 front end included in GCC prior to version 4. It is an entirely new program that has been designed to provide Fortran 95 support and extensibility for future Fortran language standards, as well as providing backwards compatibility for Fortran 77 and nearly all of the GNU language extensions supported by `g77'.  File: gfortran.info, Node: Project Status, Next: Standards, Prev: GNU Fortran and G77, Up: Introduction 1.5 Project Status ================== As soon as `gfortran' can parse all of the statements correctly, it will be in the "larva" state. When we generate code, the "puppa" state. When `gfortran' is done, we'll see if it will be a beautiful butterfly, or just a big bug.... -Andy Vaught, April 2000 The start of the GNU Fortran 95 project was announced on the GCC homepage in March 18, 2000 (even though Andy had already been working on it for a while, of course). The GNU Fortran compiler is able to compile nearly all standard-compliant Fortran 95, Fortran 90, and Fortran 77 programs, including a number of standard and non-standard extensions, and can be used on real-world programs. In particular, the supported extensions include OpenMP, Cray-style pointers, and several Fortran 2003 features such as enumeration, stream I/O, and some of the enhancements to allocatable array support from TR 15581. However, it is still under development and has a few remaining rough edges. At present, the GNU Fortran compiler passes the NIST Fortran 77 Test Suite (http://www.fortran-2000.com/ArnaudRecipes/fcvs21_f95.html), and produces acceptable results on the LAPACK Test Suite (http://www.netlib.org/lapack/faq.html#1.21). It also provides respectable performance on the Polyhedron Fortran compiler benchmarks (http://www.polyhedron.com/pb05.html) and the Livermore Fortran Kernels test (http://www.llnl.gov/asci_benchmarks/asci/limited/lfk/README.html). It has been used to compile a number of large real-world programs, including the HIRLAM weather-forecasting code (http://mysite.verizon.net/serveall/moene.pdf) and the Tonto quantum chemistry package (http://www.theochem.uwa.edu.au/tonto/); see `http://gcc.gnu.org/wiki/GfortranApps' for an extended list. Among other things, the GNU Fortran compiler is intended as a replacement for G77. At this point, nearly all programs that could be compiled with G77 can be compiled with GNU Fortran, although there are a few minor known regressions. The primary work remaining to be done on GNU Fortran falls into three categories: bug fixing (primarily regarding the treatment of invalid code and providing useful error messages), improving the compiler optimizations and the performance of compiled code, and extending the compiler to support future standards--in particular, Fortran 2003.  File: gfortran.info, Node: Standards, Prev: Project Status, Up: Introduction 1.6 Standards ============= The GNU Fortran compiler implements ISO/IEC 1539:1997 (Fortran 95). As such, it can also compile essentially all standard-compliant Fortran 90 and Fortran 77 programs. It also supports the ISO/IEC TR-15581 enhancements to allocatable arrays, and the OpenMP Application Program Interface v2.5 (http://www.openmp.org/drupal/mp-documents/spec25.pdf) specification. In the future, the GNU Fortran compiler may also support other standard variants of and extensions to the Fortran language. These include ISO/IEC 1539-1:2004 (Fortran 2003).  File: gfortran.info, Node: Invoking GNU Fortran, Next: Runtime, Prev: Introduction, Up: Top 2 GNU Fortran Command Options ***************************** The `gfortran' command supports all the options supported by the `gcc' command. Only options specific to GNU Fortran are documented here. *Note GCC Command Options: (gcc)Invoking GCC, for information on the non-Fortran-specific aspects of the `gcc' command (and, therefore, the `gfortran' command). All GCC and GNU Fortran options are accepted both by `gfortran' and by `gcc' (as well as any other drivers built at the same time, such as `g++'), since adding GNU Fortran to the GCC distribution enables acceptance of GNU Fortran options by all of the relevant drivers. In some cases, options have positive and negative forms; the negative form of `-ffoo' would be `-fno-foo'. This manual documents only one of these two forms, whichever one is not the default. * Menu: * Option Summary:: Brief list of all `gfortran' options, without explanations. * Fortran Dialect Options:: Controlling the variant of Fortran language compiled. * Error and Warning Options:: How picky should the compiler be? * Debugging Options:: Symbol tables, measurements, and debugging dumps. * Directory Options:: Where to find module files * Link Options :: Influencing the linking step * Runtime Options:: Influencing runtime behavior * Code Gen Options:: Specifying conventions for function calls, data layout and register usage. * Environment Variables:: Environment variables that affect `gfortran'.  File: gfortran.info, Node: Option Summary, Next: Fortran Dialect Options, Up: Invoking GNU Fortran 2.1 Option summary ================== Here is a summary of all the options specific to GNU Fortran, grouped by type. Explanations are in the following sections. _Fortran Language Options_ *Note Options controlling Fortran dialect: Fortran Dialect Options. -fall-intrinsics -ffree-form -fno-fixed-form -fdollar-ok -fimplicit-none -fmax-identifier-length -std=STD -fd-lines-as-code -fd-lines-as-comments -ffixed-line-length-N -ffixed-line-length-none -ffree-line-length-N -ffree-line-length-none -fdefault-double-8 -fdefault-integer-8 -fdefault-real-8 -fcray-pointer -fopenmp -fno-range-check -fbackslash -fmodule-private _Error and Warning Options_ *Note Options to request or suppress errors and warnings: Error and Warning Options. -fmax-errors=N -fsyntax-only -pedantic -pedantic-errors -Wall -Waliasing -Wampersand -Wcharacter-truncation -Wconversion -Wimplicit-interface -Wline-truncation -Wnonstd-intrinsics -Wsurprising -Wno-tabs -Wunderflow -Wunused-parameter _Debugging Options_ *Note Options for debugging your program or GNU Fortran: Debugging Options. -fdump-parse-tree -ffpe-trap=LIST -fdump-core -fbacktrace _Directory Options_ *Note Options for directory search: Directory Options. -IDIR -JDIR -MDIR -fintrinsic-modules-path DIR _Link Options_ *Note Options for influencing the linking step: Link Options. -static-libgfortran _Runtime Options_ *Note Options for influencing runtime behavior: Runtime Options. -fconvert=CONVERSION -frecord-marker=LENGTH -fmax-subrecord-length=LENGTH -fsign-zero _Code Generation Options_ *Note Options for code generation conventions: Code Gen Options. -fno-automatic -ff2c -fno-underscoring -fsecond-underscore -fbounds-check -fmax-stack-var-size=N -fpack-derived -frepack-arrays -fshort-enums -fexternal-blas -fblas-matmul-limit=N -frecursive -finit-local-zero -finit-integer=N -finit-real= -finit-logical= -finit-character=N * Menu: * Fortran Dialect Options:: Controlling the variant of Fortran language compiled. * Error and Warning Options:: How picky should the compiler be? * Debugging Options:: Symbol tables, measurements, and debugging dumps. * Directory Options:: Where to find module files * Link Options :: Influencing the linking step * Runtime Options:: Influencing runtime behavior * Code Gen Options:: Specifying conventions for function calls, data layout and register usage.  File: gfortran.info, Node: Fortran Dialect Options, Next: Error and Warning Options, Prev: Option Summary, Up: Invoking GNU Fortran 2.2 Options controlling Fortran dialect ======================================= The following options control the details of the Fortran dialect accepted by the compiler: `-ffree-form' `-ffixed-form' Specify the layout used by the source file. The free form layout was introduced in Fortran 90. Fixed form was traditionally used in older Fortran programs. When neither option is specified, the source form is determined by the file extension. `-fall-intrinsics' Accept all of the intrinsic procedures provided in libgfortran without regard to the setting of `-std'. In particular, this option can be quite useful with `-std=f95'. Additionally, `gfortran' will ignore `-Wnonstd-intrinsics'. `-fd-lines-as-code' `-fd-lines-as-comments' Enable special treatment for lines beginning with `d' or `D' in fixed form sources. If the `-fd-lines-as-code' option is given they are treated as if the first column contained a blank. If the `-fd-lines-as-comments' option is given, they are treated as comment lines. `-fdefault-double-8' Set the `DOUBLE PRECISION' type to an 8 byte wide type. `-fdefault-integer-8' Set the default integer and logical types to an 8 byte wide type. Do nothing if this is already the default. `-fdefault-real-8' Set the default real type to an 8 byte wide type. Do nothing if this is already the default. `-fdollar-ok' Allow `$' as a valid character in a symbol name. `-fbackslash' Change the interpretation of backslashes in string literals from a single backslash character to "C-style" escape characters. The following combinations are expanded \a, \b, \f, \n, \r, \t, \v, \\, and \0 to the ASCII characters alert, backspace, form feed, newline, carriage return, horizontal tab, vertical tab, backslash, and NUL, respectively. All other combinations of a character preceded by \ are unexpanded. `-fmodule-private' Set the default accessibility of module entities to `PRIVATE'. Use-associated entities will not be accessible unless they are explicitly declared as `PUBLIC'. `-ffixed-line-length-N' Set column after which characters are ignored in typical fixed-form lines in the source file, and through which spaces are assumed (as if padded to that length) after the ends of short fixed-form lines. Popular values for N include 72 (the standard and the default), 80 (card image), and 132 (corresponding to "extended-source" options in some popular compilers). N may also be `none', meaning that the entire line is meaningful and that continued character constants never have implicit spaces appended to them to fill out the line. `-ffixed-line-length-0' means the same thing as `-ffixed-line-length-none'. `-ffree-line-length-N' Set column after which characters are ignored in typical free-form lines in the source file. The default value is 132. N may be `none', meaning that the entire line is meaningful. `-ffree-line-length-0' means the same thing as `-ffree-line-length-none'. `-fmax-identifier-length=N' Specify the maximum allowed identifier length. Typical values are 31 (Fortran 95) and 63 (Fortran 2003). `-fimplicit-none' Specify that no implicit typing is allowed, unless overridden by explicit `IMPLICIT' statements. This is the equivalent of adding `implicit none' to the start of every procedure. `-fcray-pointer' Enable the Cray pointer extension, which provides C-like pointer functionality. `-fopenmp' Enable the OpenMP extensions. This includes OpenMP `!$omp' directives in free form and `c$omp', `*$omp' and `!$omp' directives in fixed form, `!$' conditional compilation sentinels in free form and `c$', `*$' and `!$' sentinels in fixed form, and when linking arranges for the OpenMP runtime library to be linked in. The option `-fopenmp' implies `-frecursive'. `-fno-range-check' Disable range checking on results of simplification of constant expressions during compilation. For example, GNU Fortran will give an error at compile time when simplifying `a = 1. / 0'. With this option, no error will be given and `a' will be assigned the value `+Infinity'. If an expression evaluates to a value outside of the relevant range of [`-HUGE()':`HUGE()'], then the expression will be replaced by `-Inf' or `+Inf' as appropriate. Similarly, `DATA i/Z'FFFFFFFF'/' will result in an integer overflow on most systems, but with `-fno-range-check' the value will "wrap around" and `i' will be initialized to -1 instead. `-std=STD' Specify the standard to which the program is expected to conform, which may be one of `f95', `f2003', `gnu', or `legacy'. The default value for STD is `gnu', which specifies a superset of the Fortran 95 standard that includes all of the extensions supported by GNU Fortran, although warnings will be given for obsolete extensions not recommended for use in new code. The `legacy' value is equivalent but without the warnings for obsolete extensions, and may be useful for old non-standard programs. The `f95' and `f2003' values specify strict conformance to the Fortran 95 and Fortran 2003 standards, respectively; errors are given for all extensions beyond the relevant language standard, and warnings are given for the Fortran 77 features that are permitted but obsolescent in later standards.  File: gfortran.info, Node: Error and Warning Options, Next: Debugging Options, Prev: Fortran Dialect Options, Up: Invoking GNU Fortran 2.3 Options to request or suppress errors and warnings ====================================================== Errors are diagnostic messages that report that the GNU Fortran compiler cannot compile the relevant piece of source code. The compiler will continue to process the program in an attempt to report further errors to aid in debugging, but will not produce any compiled output. Warnings are diagnostic messages that report constructions which are not inherently erroneous but which are risky or suggest there is likely to be a bug in the program. Unless `-Werror' is specified, they do not prevent compilation of the program. You can request many specific warnings with options beginning `-W', for example `-Wimplicit' to request warnings on implicit declarations. Each of these specific warning options also has a negative form beginning `-Wno-' to turn off warnings; for example, `-Wno-implicit'. This manual lists only one of the two forms, whichever is not the default. These options control the amount and kinds of errors and warnings produced by GNU Fortran: `-fmax-errors=N' Limits the maximum number of error messages to N, at which point GNU Fortran bails out rather than attempting to continue processing the source code. If N is 0, there is no limit on the number of error messages produced. `-fsyntax-only' Check the code for syntax errors, but don't actually compile it. This will generate module files for each module present in the code, but no other output file. `-pedantic' Issue warnings for uses of extensions to Fortran 95. `-pedantic' also applies to C-language constructs where they occur in GNU Fortran source files, such as use of `\e' in a character constant within a directive like `#include'. Valid Fortran 95 programs should compile properly with or without this option. However, without this option, certain GNU extensions and traditional Fortran features are supported as well. With this option, many of them are rejected. Some users try to use `-pedantic' to check programs for conformance. They soon find that it does not do quite what they want--it finds some nonstandard practices, but not all. However, improvements to GNU Fortran in this area are welcome. This should be used in conjunction with `-std=f95' or `-std=f2003'. `-pedantic-errors' Like `-pedantic', except that errors are produced rather than warnings. `-Wall' Enables commonly used warning options pertaining to usage that we recommend avoiding and that we believe are easy to avoid. This currently includes `-Waliasing', `-Wampersand', `-Wsurprising', `-Wnonstd-intrinsics', `-Wno-tabs', and `-Wline-truncation'. `-Waliasing' Warn about possible aliasing of dummy arguments. Specifically, it warns if the same actual argument is associated with a dummy argument with `INTENT(IN)' and a dummy argument with `INTENT(OUT)' in a call with an explicit interface. The following example will trigger the warning. interface subroutine bar(a,b) integer, intent(in) :: a integer, intent(out) :: b end subroutine end interface integer :: a call bar(a,a) `-Wampersand' Warn about missing ampersand in continued character constants. The warning is given with `-Wampersand', `-pedantic', `-std=f95', and `-std=f2003'. Note: With no ampersand given in a continued character constant, GNU Fortran assumes continuation at the first non-comment, non-whitespace character after the ampersand that initiated the continuation. `-Wcharacter-truncation' Warn when a character assignment will truncate the assigned string. `-Wconversion' Warn about implicit conversions between different types. `-Wimplicit-interface' Warn if a procedure is called without an explicit interface. Note this only checks that an explicit interface is present. It does not check that the declared interfaces are consistent across program units. `-Wnonstd-intrinsics' Warn if the user tries to use an intrinsic that does not belong to the standard the user has chosen via the `-std' option. `-Wsurprising' Produce a warning when "suspicious" code constructs are encountered. While technically legal these usually indicate that an error has been made. This currently produces a warning under the following circumstances: * An INTEGER SELECT construct has a CASE that can never be matched as its lower value is greater than its upper value. * A LOGICAL SELECT construct has three CASE statements. * A TRANSFER specifies a source that is shorter than the destination. `-Wtabs' By default, tabs are accepted as whitespace, but tabs are not members of the Fortran Character Set. For continuation lines, a tab followed by a digit between 1 and 9 is supported. `-Wno-tabs' will cause a warning to be issued if a tab is encountered. Note, `-Wno-tabs' is active for `-pedantic', `-std=f95', `-std=f2003', and `-Wall'. `-Wunderflow' Produce a warning when numerical constant expressions are encountered, which yield an UNDERFLOW during compilation. `-Wunused-parameter' Contrary to `gcc''s meaning of `-Wunused-parameter', `gfortran''s implementation of this option does not warn about unused dummy arguments, but about unused `PARAMETER' values. `-Wunused-parameter' is not included in `-Wall' but is implied by `-Wall -Wextra'. `-Werror' Turns all warnings into errors. *Note Options to Request or Suppress Errors and Warnings: (gcc)Error and Warning Options, for information on more options offered by the GBE shared by `gfortran', `gcc' and other GNU compilers. Some of these have no effect when compiling programs written in Fortran.  File: gfortran.info, Node: Debugging Options, Next: Directory Options, Prev: Error and Warning Options, Up: Invoking GNU Fortran 2.4 Options for debugging your program or GNU Fortran ===================================================== GNU Fortran has various special options that are used for debugging either your program or the GNU Fortran compiler. `-fdump-parse-tree' Output the internal parse tree before starting code generation. Only really useful for debugging the GNU Fortran compiler itself. `-ffpe-trap=LIST' Specify a list of IEEE exceptions when a Floating Point Exception (FPE) should be raised. On most systems, this will result in a SIGFPE signal being sent and the program being interrupted, producing a core file useful for debugging. LIST is a (possibly empty) comma-separated list of the following IEEE exceptions: `invalid' (invalid floating point operation, such as `SQRT(-1.0)'), `zero' (division by zero), `overflow' (overflow in a floating point operation), `underflow' (underflow in a floating point operation), `precision' (loss of precision during operation) and `denormal' (operation produced a denormal value). Some of the routines in the Fortran runtime library, like `CPU_TIME', are likely to to trigger floating point exceptions when `ffpe-trap=precision' is used. For this reason, the use of `ffpe-trap=precision' is not recommended. `-fbacktrace' Specify that, when a runtime error is encountered or a deadly signal is emitted (segmentation fault, illegal instruction, bus error or floating-point exception), the Fortran runtime library should output a backtrace of the error. This option only has influence for compilation of the Fortran main program. `-fdump-core' Request that a core-dump file is written to disk when a runtime error is encountered on systems that support core dumps. This option is only effective for the compilation of the Fortran main program. *Note Options for Debugging Your Program or GCC: (gcc)Debugging Options, for more information on debugging options.  File: gfortran.info, Node: Directory Options, Next: Link Options, Prev: Debugging Options, Up: Invoking GNU Fortran 2.5 Options for directory search ================================ These options affect how GNU Fortran searches for files specified by the `INCLUDE' directive and where it searches for previously compiled modules. It also affects the search paths used by `cpp' when used to preprocess Fortran source. `-IDIR' These affect interpretation of the `INCLUDE' directive (as well as of the `#include' directive of the `cpp' preprocessor). Also note that the general behavior of `-I' and `INCLUDE' is pretty much the same as of `-I' with `#include' in the `cpp' preprocessor, with regard to looking for `header.gcc' files and other such things. This path is also used to search for `.mod' files when previously compiled modules are required by a `USE' statement. *Note Options for Directory Search: (gcc)Directory Options, for information on the `-I' option. `-MDIR' `-JDIR' This option specifies where to put `.mod' files for compiled modules. It is also added to the list of directories to searched by an `USE' statement. The default is the current directory. `-J' is an alias for `-M' to avoid conflicts with existing GCC options. `-fintrinsic-modules-path DIR' This option specifies the location of pre-compiled intrinsic modules, if they are not in the default location expected by the compiler.  File: gfortran.info, Node: Link Options, Next: Runtime Options, Prev: Directory Options, Up: Invoking GNU Fortran 2.6 Influencing the linking step ================================ These options come into play when the compiler links object files into an executable output file. They are meaningless if the compiler is not doing a link step. `-static-libgfortran' On systems that provide `libgfortran' as a shared and a static library, this option forces the use of the static version. If no shared version of `libgfortran' was built when the compiler was configured, this option has no effect.  File: gfortran.info, Node: Runtime Options, Next: Code Gen Options, Prev: Link Options, Up: Invoking GNU Fortran 2.7 Influencing runtime behavior ================================ These options affect the runtime behavior of programs compiled with GNU Fortran. `-fconvert=CONVERSION' Specify the representation of data for unformatted files. Valid values for conversion are: `native', the default; `swap', swap between big- and little-endian; `big-endian', use big-endian representation for unformatted files; `little-endian', use little-endian representation for unformatted files. _This option has an effect only when used in the main program. The `CONVERT' specifier and the GFORTRAN_CONVERT_UNIT environment variable override the default specified by `-fconvert'._ `-frecord-marker=LENGTH' Specify the length of record markers for unformatted files. Valid values for LENGTH are 4 and 8. Default is 4. _This is different from previous versions of `gfortran'_, which specified a default record marker length of 8 on most systems. If you want to read or write files compatible with earlier versions of `gfortran', use `-frecord-marker=8'. `-fmax-subrecord-length=LENGTH' Specify the maximum length for a subrecord. The maximum permitted value for length is 2147483639, which is also the default. Only really useful for use by the gfortran testsuite. `-fsign-zero' When writing zero values, show the negative sign if the sign bit is set. `fno-sign-zero' does not print the negative sign of zero values for compatibility with F77. Default behavior is to show the negative sign.  File: gfortran.info, Node: Code Gen Options, Next: Environment Variables, Prev: Runtime Options, Up: Invoking GNU Fortran 2.8 Options for code generation conventions =========================================== These machine-independent options control the interface conventions used in code generation. Most of them have both positive and negative forms; the negative form of `-ffoo' would be `-fno-foo'. In the table below, only one of the forms is listed--the one which is not the default. You can figure out the other form by either removing `no-' or adding it. `-fno-automatic' Treat each program unit (except those marked as RECURSIVE) as if the `SAVE' statement were specified for every local variable and array referenced in it. Does not affect common blocks. (Some Fortran compilers provide this option under the name `-static' or `-save'.) The default, which is `-fautomatic', uses the stack for local variables smaller than the value given by `-fmax-stack-var-size'. Use the option `-frecursive' to use no static memory. `-ff2c' Generate code designed to be compatible with code generated by `g77' and `f2c'. The calling conventions used by `g77' (originally implemented in `f2c') require functions that return type default `REAL' to actually return the C type `double', and functions that return type `COMPLEX' to return the values via an extra argument in the calling sequence that points to where to store the return value. Under the default GNU calling conventions, such functions simply return their results as they would in GNU C--default `REAL' functions return the C type `float', and `COMPLEX' functions return the GNU C type `complex'. Additionally, this option implies the `-fsecond-underscore' option, unless `-fno-second-underscore' is explicitly requested. This does not affect the generation of code that interfaces with the `libgfortran' library. _Caution:_ It is not a good idea to mix Fortran code compiled with `-ff2c' with code compiled with the default `-fno-f2c' calling conventions as, calling `COMPLEX' or default `REAL' functions between program parts which were compiled with different calling conventions will break at execution time. _Caution:_ This will break code which passes intrinsic functions of type default `REAL' or `COMPLEX' as actual arguments, as the library implementations use the `-fno-f2c' calling conventions. `-fno-underscoring' Do not transform names of entities specified in the Fortran source file by appending underscores to them. With `-funderscoring' in effect, GNU Fortran appends one underscore to external names with no underscores. This is done to ensure compatibility with code produced by many UNIX Fortran compilers. _Caution_: The default behavior of GNU Fortran is incompatible with `f2c' and `g77', please use the `-ff2c' option if you want object files compiled with GNU Fortran to be compatible with object code created with these tools. Use of `-fno-underscoring' is not recommended unless you are experimenting with issues such as integration of GNU Fortran into existing system environments (vis-a`-vis existing libraries, tools, and so on). For example, with `-funderscoring', and assuming other defaults like `-fcase-lower' and that `j()' and `max_count()' are external functions while `my_var' and `lvar' are local variables, a statement like I = J() + MAX_COUNT (MY_VAR, LVAR) is implemented as something akin to: i = j_() + max_count__(&my_var__, &lvar); With `-fno-underscoring', the same statement is implemented as: i = j() + max_count(&my_var, &lvar); Use of `-fno-underscoring' allows direct specification of user-defined names while debugging and when interfacing GNU Fortran code with other languages. Note that just because the names match does _not_ mean that the interface implemented by GNU Fortran for an external name matches the interface implemented by some other language for that same name. That is, getting code produced by GNU Fortran to link to code produced by some other compiler using this or any other method can be only a small part of the overall solution--getting the code generated by both compilers to agree on issues other than naming can require significant effort, and, unlike naming disagreements, linkers normally cannot detect disagreements in these other areas. Also, note that with `-fno-underscoring', the lack of appended underscores introduces the very real possibility that a user-defined external name will conflict with a name in a system library, which could make finding unresolved-reference bugs quite difficult in some cases--they might occur at program run time, and show up only as buggy behavior at run time. In future versions of GNU Fortran we hope to improve naming and linking issues so that debugging always involves using the names as they appear in the source, even if the names as seen by the linker are mangled to prevent accidental linking between procedures with incompatible interfaces. `-fsecond-underscore' By default, GNU Fortran appends an underscore to external names. If this option is used GNU Fortran appends two underscores to names with underscores and one underscore to external names with no underscores. GNU Fortran also appends two underscores to internal names with underscores to avoid naming collisions with external names. This option has no effect if `-fno-underscoring' is in effect. It is implied by the `-ff2c' option. Otherwise, with this option, an external name such as `MAX_COUNT' is implemented as a reference to the link-time external symbol `max_count__', instead of `max_count_'. This is required for compatibility with `g77' and `f2c', and is implied by use of the `-ff2c' option. `-fbounds-check' Enable generation of run-time checks for array subscripts and against the declared minimum and maximum values. It also checks array indices for assumed and deferred shape arrays against the actual allocated bounds. Some checks require that `-fbounds-check' is set for the compilation of the main program. In the future this may also include other forms of checking, e.g., checking substring references. `-fmax-stack-var-size=N' This option specifies the size in bytes of the largest array that will be put on the stack; if the size is exceeded static memory is used (except in procedures marked as RECURSIVE). Use the option `-frecursive' to allow for recursive procedures which do not have a RECURSIVE attribute or for parallel programs. Use `-fno-automatic' to never use the stack. This option currently only affects local arrays declared with constant bounds, and may not apply to all character variables. Future versions of GNU Fortran may improve this behavior. The default value for N is 32768. `-fpack-derived' This option tells GNU Fortran to pack derived type members as closely as possible. Code compiled with this option is likely to be incompatible with code compiled without this option, and may execute slower. `-frepack-arrays' In some circumstances GNU Fortran may pass assumed shape array sections via a descriptor describing a noncontiguous area of memory. This option adds code to the function prologue to repack the data into a contiguous block at runtime. This should result in faster accesses to the array. However it can introduce significant overhead to the function call, especially when the passed data is noncontiguous. `-fshort-enums' This option is provided for interoperability with C code that was compiled with the `-fshort-enums' option. It will make GNU Fortran choose the smallest `INTEGER' kind a given enumerator set will fit in, and give all its enumerators this kind. `-fexternal-blas' This option will make `gfortran' generate calls to BLAS functions for some matrix operations like `MATMUL', instead of using our own algorithms, if the size of the matrices involved is larger than a given limit (see `-fblas-matmul-limit'). This may be profitable if an optimized vendor BLAS library is available. The BLAS library will have to be specified at link time. `-fblas-matmul-limit=N' Only significant when `-fexternal-blas' is in effect. Matrix multiplication of matrices with size larger than (or equal to) N will be performed by calls to BLAS functions, while others will be handled by `gfortran' internal algorithms. If the matrices involved are not square, the size comparison is performed using the geometric mean of the dimensions of the argument and result matrices. The default value for N is 30. `-frecursive' Allow indirect recursion by forcing all local arrays to be allocated on the stack. This flag cannot be used together with `-fmax-stack-var-size=' or `-fno-automatic'. `-finit-local-zero' `-finit-integer=N' `-finit-real=' `-finit-logical=' `-finit-character=N' The `-finit-local-zero' option instructs the compiler to initialize local `INTEGER', `REAL', and `COMPLEX' variables to zero, `LOGICAL' variables to false, and `CHARACTER' variables to a string of null bytes. Finer-grained initialization options are provided by the `-finit-integer=N', `-finit-real=' (which also initializes the real and imaginary parts of local `COMPLEX' variables), `-finit-logical=', and `-finit-character=N' (where N is an ASCII character value) options. These options do not initialize components of derived type variables, nor do they initialize variables that appear in an `EQUIVALENCE' statement. (This limitation may be removed in future releases). Note that the `-finit-real=nan' option initializes `REAL' and `COMPLEX' variables with a quiet NaN. *Note Options for Code Generation Conventions: (gcc)Code Gen Options, for information on more options offered by the GBE shared by `gfortran', `gcc', and other GNU compilers.  File: gfortran.info, Node: Environment Variables, Prev: Code Gen Options, Up: Invoking GNU Fortran 2.9 Environment variables affecting `gfortran' ============================================== The `gfortran' compiler currently does not make use of any environment variables to control its operation above and beyond those that affect the operation of `gcc'. *Note Environment Variables Affecting GCC: (gcc)Environment Variables, for information on environment variables. *Note Runtime::, for environment variables that affect the run-time behavior of programs compiled with GNU Fortran.  File: gfortran.info, Node: Runtime, Next: Fortran 2003 status, Prev: Invoking GNU Fortran, Up: Top 3 Runtime: Influencing runtime behavior with environment variables ******************************************************************* The behavior of the `gfortran' can be influenced by environment variables. Malformed environment variables are silently ignored. * Menu: * GFORTRAN_STDIN_UNIT:: Unit number for standard input * GFORTRAN_STDOUT_UNIT:: Unit number for standard output * GFORTRAN_STDERR_UNIT:: Unit number for standard error * GFORTRAN_USE_STDERR:: Send library output to standard error * GFORTRAN_TMPDIR:: Directory for scratch files * GFORTRAN_UNBUFFERED_ALL:: Don't buffer I/O for all units. * GFORTRAN_UNBUFFERED_PRECONNECTED:: Don't buffer I/O for preconnected units. * GFORTRAN_SHOW_LOCUS:: Show location for runtime errors * GFORTRAN_OPTIONAL_PLUS:: Print leading + where permitted * GFORTRAN_DEFAULT_RECL:: Default record length for new files * GFORTRAN_LIST_SEPARATOR:: Separator for list output * GFORTRAN_CONVERT_UNIT:: Set endianness for unformatted I/O * GFORTRAN_ERROR_DUMPCORE:: Dump core on run-time errors * GFORTRAN_ERROR_BACKTRACE:: Show backtrace on run-time errors  File: gfortran.info, Node: GFORTRAN_STDIN_UNIT, Next: GFORTRAN_STDOUT_UNIT, Up: Runtime 3.1 `GFORTRAN_STDIN_UNIT'--Unit number for standard input ========================================================= This environment variable can be used to select the unit number preconnected to standard input. This must be a positive integer. The default value is 5.  File: gfortran.info, Node: GFORTRAN_STDOUT_UNIT, Next: GFORTRAN_STDERR_UNIT, Prev: GFORTRAN_STDIN_UNIT, Up: Runtime 3.2 `GFORTRAN_STDOUT_UNIT'--Unit number for standard output =========================================================== This environment variable can be used to select the unit number preconnected to standard output. This must be a positive integer. The default value is 6.  File: gfortran.info, Node: GFORTRAN_STDERR_UNIT, Next: GFORTRAN_USE_STDERR, Prev: GFORTRAN_STDOUT_UNIT, Up: Runtime 3.3 `GFORTRAN_STDERR_UNIT'--Unit number for standard error ========================================================== This environment variable can be used to select the unit number preconnected to standard error. This must be a positive integer. The default value is 0.  File: gfortran.info, Node: GFORTRAN_USE_STDERR, Next: GFORTRAN_TMPDIR, Prev: GFORTRAN_STDERR_UNIT, Up: Runtime 3.4 `GFORTRAN_USE_STDERR'--Send library output to standard error ================================================================ This environment variable controls where library output is sent. If the first letter is `y', `Y' or `1', standard error is used. If the first letter is `n', `N' or `0', standard output is used.  File: gfortran.info, Node: GFORTRAN_TMPDIR, Next: GFORTRAN_UNBUFFERED_ALL, Prev: GFORTRAN_USE_STDERR, Up: Runtime 3.5 `GFORTRAN_TMPDIR'--Directory for scratch files ================================================== This environment variable controls where scratch files are created. If this environment variable is missing, GNU Fortran searches for the environment variable `TMP'. If this is also missing, the default is `/tmp'.  File: gfortran.info, Node: GFORTRAN_UNBUFFERED_ALL, Next: GFORTRAN_UNBUFFERED_PRECONNECTED, Prev: GFORTRAN_TMPDIR, Up: Runtime 3.6 `GFORTRAN_UNBUFFERED_ALL'--Don't buffer I/O on all units ============================================================ This environment variable controls whether all I/O is unbuffered. If the first letter is `y', `Y' or `1', all I/O is unbuffered. This will slow down small sequential reads and writes. If the first letter is `n', `N' or `0', I/O is buffered. This is the default.  File: gfortran.info, Node: GFORTRAN_UNBUFFERED_PRECONNECTED, Next: GFORTRAN_SHOW_LOCUS, Prev: GFORTRAN_UNBUFFERED_ALL, Up: Runtime 3.7 `GFORTRAN_UNBUFFERED_PRECONNECTED'--Don't buffer I/O on preconnected units ============================================================================== The environment variable named `GFORTRAN_UNBUFFERED_PRECONNECTED' controls whether I/O on a preconnected unit (i.e STDOUT or STDERR) is unbuffered. If the first letter is `y', `Y' or `1', I/O is unbuffered. This will slow down small sequential reads and writes. If the first letter is `n', `N' or `0', I/O is buffered. This is the default.  File: gfortran.info, Node: GFORTRAN_SHOW_LOCUS, Next: GFORTRAN_OPTIONAL_PLUS, Prev: GFORTRAN_UNBUFFERED_PRECONNECTED, Up: Runtime 3.8 `GFORTRAN_SHOW_LOCUS'--Show location for runtime errors =========================================================== If the first letter is `y', `Y' or `1', filename and line numbers for runtime errors are printed. If the first letter is `n', `N' or `0', don't print filename and line numbers for runtime errors. The default is to print the location.  File: gfortran.info, Node: GFORTRAN_OPTIONAL_PLUS, Next: GFORTRAN_DEFAULT_RECL, Prev: GFORTRAN_SHOW_LOCUS, Up: Runtime 3.9 `GFORTRAN_OPTIONAL_PLUS'--Print leading + where permitted ============================================================= If the first letter is `y', `Y' or `1', a plus sign is printed where permitted by the Fortran standard. If the first letter is `n', `N' or `0', a plus sign is not printed in most cases. Default is not to print plus signs.  File: gfortran.info, Node: GFORTRAN_DEFAULT_RECL, Next: GFORTRAN_LIST_SEPARATOR, Prev: GFORTRAN_OPTIONAL_PLUS, Up: Runtime 3.10 `GFORTRAN_DEFAULT_RECL'--Default record length for new files ================================================================= This environment variable specifies the default record length, in bytes, for files which are opened without a `RECL' tag in the `OPEN' statement. This must be a positive integer. The default value is 1073741824 bytes (1 GB).  File: gfortran.info, Node: GFORTRAN_LIST_SEPARATOR, Next: GFORTRAN_CONVERT_UNIT, Prev: GFORTRAN_DEFAULT_RECL, Up: Runtime 3.11 `GFORTRAN_LIST_SEPARATOR'--Separator for list output ========================================================= This environment variable specifies the separator when writing list-directed output. It may contain any number of spaces and at most one comma. If you specify this on the command line, be sure to quote spaces, as in $ GFORTRAN_LIST_SEPARATOR=' , ' ./a.out when `a.out' is the compiled Fortran program that you want to run. Default is a single space.  File: gfortran.info, Node: GFORTRAN_CONVERT_UNIT, Next: GFORTRAN_ERROR_DUMPCORE, Prev: GFORTRAN_LIST_SEPARATOR, Up: Runtime 3.12 `GFORTRAN_CONVERT_UNIT'--Set endianness for unformatted I/O ================================================================ By setting the `GFORTRAN_CONVERT_UNIT' variable, it is possible to change the representation of data for unformatted files. The syntax for the `GFORTRAN_CONVERT_UNIT' variable is: GFORTRAN_CONVERT_UNIT: mode | mode ';' exception | exception ; mode: 'native' | 'swap' | 'big_endian' | 'little_endian' ; exception: mode ':' unit_list | unit_list ; unit_list: unit_spec | unit_list unit_spec ; unit_spec: INTEGER | INTEGER '-' INTEGER ; The variable consists of an optional default mode, followed by a list of optional exceptions, which are separated by semicolons from the preceding default and each other. Each exception consists of a format and a comma-separated list of units. Valid values for the modes are the same as for the `CONVERT' specifier: `NATIVE' Use the native format. This is the default. `SWAP' Swap between little- and big-endian. `LITTLE_ENDIAN' Use the little-endian format for unformatted files. `BIG_ENDIAN' Use the big-endian format for unformatted files. A missing mode for an exception is taken to mean `BIG_ENDIAN'. Examples of values for `GFORTRAN_CONVERT_UNIT' are: `'big_endian'' Do all unformatted I/O in big_endian mode. `'little_endian;native:10-20,25'' Do all unformatted I/O in little_endian mode, except for units 10 to 20 and 25, which are in native format. `'10-20'' Units 10 to 20 are big-endian, the rest is native. Setting the environment variables should be done on the command line or via the `export' command for `sh'-compatible shells and via `setenv' for `csh'-compatible shells. Example for `sh': $ gfortran foo.f90 $ GFORTRAN_CONVERT_UNIT='big_endian;native:10-20' ./a.out Example code for `csh': % gfortran foo.f90 % setenv GFORTRAN_CONVERT_UNIT 'big_endian;native:10-20' % ./a.out Using anything but the native representation for unformatted data carries a significant speed overhead. If speed in this area matters to you, it is best if you use this only for data that needs to be portable. *Note CONVERT specifier::, for an alternative way to specify the data representation for unformatted files. *Note Runtime Options::, for setting a default data representation for the whole program. The `CONVERT' specifier overrides the `-fconvert' compile options. _Note that the values specified via the GFORTRAN_CONVERT_UNIT environment variable will override the CONVERT specifier in the open statement_. This is to give control over data formats to users who do not have the source code of their program available.  File: gfortran.info, Node: GFORTRAN_ERROR_DUMPCORE, Next: GFORTRAN_ERROR_BACKTRACE, Prev: GFORTRAN_CONVERT_UNIT, Up: Runtime 3.13 `GFORTRAN_ERROR_DUMPCORE'--Dump core on run-time errors ============================================================ If the `GFORTRAN_ERROR_DUMPCORE' variable is set to `y', `Y' or `1' (only the first letter is relevant) then library run-time errors cause core dumps. To disable the core dumps, set the variable to `n', `N', `0'. Default is not to core dump unless the `-fdump-core' compile option was used.  File: gfortran.info, Node: GFORTRAN_ERROR_BACKTRACE, Prev: GFORTRAN_ERROR_DUMPCORE, Up: Runtime 3.14 `GFORTRAN_ERROR_BACKTRACE'--Show backtrace on run-time errors ================================================================== If the `GFORTRAN_ERROR_BACKTRACE' variable is set to `y', `Y' or `1' (only the first letter is relevant) then a backtrace is printed when a run-time error occurs. To disable the backtracing, set the variable to `n', `N', `0'. Default is not to print a backtrace unless the `-fbacktrace' compile option was used.  File: gfortran.info, Node: Fortran 2003 status, Next: Extensions, Prev: Runtime, Up: Top 4 Fortran 2003 Status ********************* Although GNU Fortran focuses on implementing the Fortran 95 standard for the time being, a few Fortran 2003 features are currently available. * Intrinsics `command_argument_count', `get_command', `get_command_argument', `get_environment_variable', and `move_alloc'. * Array constructors using square brackets. That is, `[...]' rather than `(/.../)'. * `FLUSH' statement. * `IOMSG=' specifier for I/O statements. * Support for the declaration of enumeration constants via the `ENUM' and `ENUMERATOR' statements. Interoperability with `gcc' is guaranteed also for the case where the `-fshort-enums' command line option is given. * TR 15581: * `ALLOCATABLE' dummy arguments. * `ALLOCATABLE' function results * `ALLOCATABLE' components of derived types * The `OPEN' statement supports the `ACCESS='STREAM'' specifier, allowing I/O without any record structure. * Namelist input/output for internal files. * The `PROTECTED' statement and attribute. * The `VALUE' statement and attribute. * The `VOLATILE' statement and attribute. * The `IMPORT' statement, allowing to import host-associated derived types. * `USE' statement with `INTRINSIC' and `NON_INTRINSIC' attribute; supported intrinsic modules: `ISO_FORTRAN_ENV', `OMP_LIB' and `OMP_LIB_KINDS'. * Renaming of operators in the `USE' statement. * Interoperability with C (ISO C Bindings) * BOZ as argument of INT, REAL, DBLE and CMPLX.  File: gfortran.info, Node: Extensions, Next: Intrinsic Procedures, Prev: Fortran 2003 status, Up: Top 5 Extensions ************ The two sections below detail the extensions to standard Fortran that are implemented in GNU Fortran, as well as some of the popular or historically important extensions that are not (or not yet) implemented. For the latter case, we explain the alternatives available to GNU Fortran users, including replacement by standard-conforming code or GNU extensions. * Menu: * Extensions implemented in GNU Fortran:: * Extensions not implemented in GNU Fortran::  File: gfortran.info, Node: Extensions implemented in GNU Fortran, Next: Extensions not implemented in GNU Fortran, Up: Extensions 5.1 Extensions implemented in GNU Fortran ========================================= GNU Fortran implements a number of extensions over standard Fortran. This chapter contains information on their syntax and meaning. There are currently two categories of GNU Fortran extensions, those that provide functionality beyond that provided by any standard, and those that are supported by GNU Fortran purely for backward compatibility with legacy compilers. By default, `-std=gnu' allows the compiler to accept both types of extensions, but to warn about the use of the latter. Specifying either `-std=f95' or `-std=f2003' disables both types of extensions, and `-std=legacy' allows both without warning. * Menu: * Old-style kind specifications:: * Old-style variable initialization:: * Extensions to namelist:: * X format descriptor without count field:: * Commas in FORMAT specifications:: * Missing period in FORMAT specifications:: * I/O item lists:: * BOZ literal constants:: * Real array indices:: * Unary operators:: * Implicitly convert LOGICAL and INTEGER values:: * Hollerith constants support:: * Cray pointers:: * CONVERT specifier:: * OpenMP:: * Argument list functions::  File: gfortran.info, Node: Old-style kind specifications, Next: Old-style variable initialization, Up: Extensions implemented in GNU Fortran 5.1.1 Old-style kind specifications ----------------------------------- GNU Fortran allows old-style kind specifications in declarations. These look like: TYPESPEC*size x,y,z where `TYPESPEC' is a basic type (`INTEGER', `REAL', etc.), and where `size' is a byte count corresponding to the storage size of a valid kind for that type. (For `COMPLEX' variables, `size' is the total size of the real and imaginary parts.) The statement then declares `x', `y' and `z' to be of type `TYPESPEC' with the appropriate kind. This is equivalent to the standard-conforming declaration TYPESPEC(k) x,y,z where `k' is equal to `size' for most types, but is equal to `size/2' for the `COMPLEX' type.  File: gfortran.info, Node: Old-style variable initialization, Next: Extensions to namelist, Prev: Old-style kind specifications, Up: Extensions implemented in GNU Fortran 5.1.2 Old-style variable initialization --------------------------------------- GNU Fortran allows old-style initialization of variables of the form: INTEGER i/1/,j/2/ REAL x(2,2) /3*0.,1./ The syntax for the initializers is as for the `DATA' statement, but unlike in a `DATA' statement, an initializer only applies to the variable immediately preceding the initialization. In other words, something like `INTEGER I,J/2,3/' is not valid. This style of initialization is only allowed in declarations without double colons (`::'); the double colons were introduced in Fortran 90, which also introduced a standard syntax for initializing variables in type declarations. Examples of standard-conforming code equivalent to the above example are: ! Fortran 90 INTEGER :: i = 1, j = 2 REAL :: x(2,2) = RESHAPE((/0.,0.,0.,1./),SHAPE(x)) ! Fortran 77 INTEGER i, j REAL x(2,2) DATA i/1/, j/2/, x/3*0.,1./ Note that variables which are explicitly initialized in declarations or in `DATA' statements automatically acquire the `SAVE' attribute.  File: gfortran.info, Node: Extensions to namelist, Next: X format descriptor without count field, Prev: Old-style variable initialization, Up: Extensions implemented in GNU Fortran 5.1.3 Extensions to namelist ---------------------------- GNU Fortran fully supports the Fortran 95 standard for namelist I/O including array qualifiers, substrings and fully qualified derived types. The output from a namelist write is compatible with namelist read. The output has all names in upper case and indentation to column 1 after the namelist name. Two extensions are permitted: Old-style use of `$' instead of `&' $MYNML X(:)%Y(2) = 1.0 2.0 3.0 CH(1:4) = "abcd" $END It should be noted that the default terminator is `/' rather than `&END'. Querying of the namelist when inputting from stdin. After at least one space, entering `?' sends to stdout the namelist name and the names of the variables in the namelist: ? &mynml x x%y ch &end Entering `=?' outputs the namelist to stdout, as if `WRITE(*,NML = mynml)' had been called: =? &MYNML X(1)%Y= 0.000000 , 1.000000 , 0.000000 , X(2)%Y= 0.000000 , 2.000000 , 0.000000 , X(3)%Y= 0.000000 , 3.000000 , 0.000000 , CH=abcd, / To aid this dialog, when input is from stdin, errors send their messages to stderr and execution continues, even if `IOSTAT' is set. `PRINT' namelist is permitted. This causes an error if `-std=f95' is used. PROGRAM test_print REAL, dimension (4) :: x = (/1.0, 2.0, 3.0, 4.0/) NAMELIST /mynml/ x PRINT mynml END PROGRAM test_print Expanded namelist reads are permitted. This causes an error if `-std=f95' is used. In the following example, the first element of the array will be given the value 0.00 and the two succeeding elements will be given the values 1.00 and 2.00. &MYNML X(1,1) = 0.00 , 1.00 , 2.00 /  File: gfortran.info, Node: X format descriptor without count field, Next: Commas in FORMAT specifications, Prev: Extensions to namelist, Up: Extensions implemented in GNU Fortran 5.1.4 `X' format descriptor without count field ----------------------------------------------- To support legacy codes, GNU Fortran permits the count field of the `X' edit descriptor in `FORMAT' statements to be omitted. When omitted, the count is implicitly assumed to be one. PRINT 10, 2, 3 10 FORMAT (I1, X, I1)  File: gfortran.info, Node: Commas in FORMAT specifications, Next: Missing period in FORMAT specifications, Prev: X format descriptor without count field, Up: Extensions implemented in GNU Fortran 5.1.5 Commas in `FORMAT' specifications --------------------------------------- To support legacy codes, GNU Fortran allows the comma separator to be omitted immediately before and after character string edit descriptors in `FORMAT' statements. PRINT 10, 2, 3 10 FORMAT ('FOO='I1' BAR='I2)  File: gfortran.info, Node: Missing period in FORMAT specifications, Next: I/O item lists, Prev: Commas in FORMAT specifications, Up: Extensions implemented in GNU Fortran 5.1.6 Missing period in `FORMAT' specifications ----------------------------------------------- To support legacy codes, GNU Fortran allows missing periods in format specifications if and only if `-std=legacy' is given on the command line. This is considered non-conforming code and is discouraged. REAL :: value READ(*,10) value 10 FORMAT ('F4')  File: gfortran.info, Node: I/O item lists, Next: BOZ literal constants, Prev: Missing period in FORMAT specifications, Up: Extensions implemented in GNU Fortran 5.1.7 I/O item lists -------------------- To support legacy codes, GNU Fortran allows the input item list of the `READ' statement, and the output item lists of the `WRITE' and `PRINT' statements, to start with a comma.  File: gfortran.info, Node: BOZ literal constants, Next: Real array indices, Prev: I/O item lists, Up: Extensions implemented in GNU Fortran 5.1.8 BOZ literal constants --------------------------- Besides decimal constants, Fortran also supports binary (`b'), octal (`o') and hexadecimal (`z') integer constants. The syntax is: `prefix quote digits quote', were the prefix is either `b', `o' or `z', quote is either `'' or `"' and the digits are for binary `0' or `1', for octal between `0' and `7', and for hexadecimal between `0' and `F'. (Example: `b'01011101''.) Up to Fortran 95, BOZ literals were only allowed to initialize integer variables in DATA statements. Since Fortran 2003 BOZ literals are also allowed as argument of `REAL', `DBLE', `INT' and `CMPLX'; the result is the same as if the integer BOZ literal had been converted by `TRANSFER' to, respectively, `real', `double precision', `integer' or `complex'. As GNU Fortran extension the intrinsic procedures `FLOAT', `DFLOAT', `COMPLEX' and `DCMPLX' are treated alike. As an extension, GNU Fortran allows hexadecimal BOZ literal constants to be specified using the `X' prefix, in addition to the standard `Z' prefix. The BOZ literal can also be specified by adding a suffix to the string, for example, `Z'ABC'' and `'ABC'Z' are equivalent. Furthermore, GNU Fortran allows using BOZ literal constants outside DATA statements and the four intrinsic functions allowed by Fortran 2003. In DATA statements, in direct assignments, where the right-hand side only contains a BOZ literal constant, and for old-style initializers of the form `integer i /o'0173'/', the constant is transferred as if `TRANSFER' had been used; for `COMPLEX' numbers, only the real part is initialized unless `CMPLX' is used. In all other cases, the BOZ literal constant is converted to an `INTEGER' value with the largest decimal representation. This value is then converted numerically to the type and kind of the variable in question. (For instance `real :: r = b'0000001' + 1' initializes `r' with `2.0'.) As different compilers implement the extension differently, one should be careful when doing bitwise initialization of non-integer variables. Note that initializing an `INTEGER' variable with a statement such as `DATA i/Z'FFFFFFFF'/' will give an integer overflow error rather than the desired result of -1 when `i' is a 32-bit integer on a system that supports 64-bit integers. The `-fno-range-check' option can be used as a workaround for legacy code that initializes integers in this manner.  File: gfortran.info, Node: Real array indices, Next: Unary operators, Prev: BOZ literal constants, Up: Extensions implemented in GNU Fortran 5.1.9 Real array indices ------------------------ As an extension, GNU Fortran allows the use of `REAL' expressions or variables as array indices.  File: gfortran.info, Node: Unary operators, Next: Implicitly convert LOGICAL and INTEGER values, Prev: Real array indices, Up: Extensions implemented in GNU Fortran 5.1.10 Unary operators ---------------------- As an extension, GNU Fortran allows unary plus and unary minus operators to appear as the second operand of binary arithmetic operators without the need for parenthesis. X = Y * -Z  File: gfortran.info, Node: Implicitly convert LOGICAL and INTEGER values, Next: Hollerith constants support, Prev: Unary operators, Up: Extensions implemented in GNU Fortran 5.1.11 Implicitly convert `LOGICAL' and `INTEGER' values -------------------------------------------------------- As an extension for backwards compatibility with other compilers, GNU Fortran allows the implicit conversion of `LOGICAL' values to `INTEGER' values and vice versa. When converting from a `LOGICAL' to an `INTEGER', `.FALSE.' is interpreted as zero, and `.TRUE.' is interpreted as one. When converting from `INTEGER' to `LOGICAL', the value zero is interpreted as `.FALSE.' and any nonzero value is interpreted as `.TRUE.'. LOGICAL :: l l = 1 INTEGER :: i i = .TRUE. However, there is no implicit conversion of `INTEGER' values in `if'-statements, nor of `LOGICAL' or `INTEGER' values in I/O operations.  File: gfortran.info, Node: Hollerith constants support, Next: Cray pointers, Prev: Implicitly convert LOGICAL and INTEGER values, Up: Extensions implemented in GNU Fortran 5.1.12 Hollerith constants support ---------------------------------- GNU Fortran supports Hollerith constants in assignments, function arguments, and `DATA' and `ASSIGN' statements. A Hollerith constant is written as a string of characters preceded by an integer constant indicating the character count, and the letter `H' or `h', and stored in bytewise fashion in a numeric (`INTEGER', `REAL', or `complex') or `LOGICAL' variable. The constant will be padded or truncated to fit the size of the variable in which it is stored. Examples of valid uses of Hollerith constants: complex*16 x(2) data x /16Habcdefghijklmnop, 16Hqrstuvwxyz012345/ x(1) = 16HABCDEFGHIJKLMNOP call foo (4h abc) Invalid Hollerith constants examples: integer*4 a a = 8H12345678 ! Valid, but the Hollerith constant will be truncated. a = 0H ! At least one character is needed. In general, Hollerith constants were used to provide a rudimentary facility for handling character strings in early Fortran compilers, prior to the introduction of `CHARACTER' variables in Fortran 77; in those cases, the standard-compliant equivalent is to convert the program to use proper character strings. On occasion, there may be a case where the intent is specifically to initialize a numeric variable with a given byte sequence. In these cases, the same result can be obtained by using the `TRANSFER' statement, as in this example. INTEGER(KIND=4) :: a a = TRANSFER ("abcd", a) ! equivalent to: a = 4Habcd  File: gfortran.info, Node: Cray pointers, Next: CONVERT specifier, Prev: Hollerith constants support, Up: Extensions implemented in GNU Fortran 5.1.13 Cray pointers -------------------- Cray pointers are part of a non-standard extension that provides a C-like pointer in Fortran. This is accomplished through a pair of variables: an integer "pointer" that holds a memory address, and a "pointee" that is used to dereference the pointer. Pointer/pointee pairs are declared in statements of the form: pointer ( , ) or, pointer ( , ), ( , ), ... The pointer is an integer that is intended to hold a memory address. The pointee may be an array or scalar. A pointee can be an assumed size array--that is, the last dimension may be left unspecified by using a `*' in place of a value--but a pointee cannot be an assumed shape array. No space is allocated for the pointee. The pointee may have its type declared before or after the pointer statement, and its array specification (if any) may be declared before, during, or after the pointer statement. The pointer may be declared as an integer prior to the pointer statement. However, some machines have default integer sizes that are different than the size of a pointer, and so the following code is not portable: integer ipt pointer (ipt, iarr) If a pointer is declared with a kind that is too small, the compiler will issue a warning; the resulting binary will probably not work correctly, because the memory addresses stored in the pointers may be truncated. It is safer to omit the first line of the above example; if explicit declaration of ipt's type is omitted, then the compiler will ensure that ipt is an integer variable large enough to hold a pointer. Pointer arithmetic is valid with Cray pointers, but it is not the same as C pointer arithmetic. Cray pointers are just ordinary integers, so the user is responsible for determining how many bytes to add to a pointer in order to increment it. Consider the following example: real target(10) real pointee(10) pointer (ipt, pointee) ipt = loc (target) ipt = ipt + 1 The last statement does not set `ipt' to the address of `target(1)', as it would in C pointer arithmetic. Adding `1' to `ipt' just adds one byte to the address stored in `ipt'. Any expression involving the pointee will be translated to use the value stored in the pointer as the base address. To get the address of elements, this extension provides an intrinsic function `LOC()'. The `LOC()' function is equivalent to the `&' operator in C, except the address is cast to an integer type: real ar(10) pointer(ipt, arpte(10)) real arpte ipt = loc(ar) ! Makes arpte is an alias for ar arpte(1) = 1.0 ! Sets ar(1) to 1.0 The pointer can also be set by a call to the `MALLOC' intrinsic (see *note MALLOC::). Cray pointees often are used to alias an existing variable. For example: integer target(10) integer iarr(10) pointer (ipt, iarr) ipt = loc(target) As long as `ipt' remains unchanged, `iarr' is now an alias for `target'. The optimizer, however, will not detect this aliasing, so it is unsafe to use `iarr' and `target' simultaneously. Using a pointee in any way that violates the Fortran aliasing rules or assumptions is illegal. It is the user's responsibility to avoid doing this; the compiler works under the assumption that no such aliasing occurs. Cray pointers will work correctly when there is no aliasing (i.e., when they are used to access a dynamically allocated block of memory), and also in any routine where a pointee is used, but any variable with which it shares storage is not used. Code that violates these rules may not run as the user intends. This is not a bug in the optimizer; any code that violates the aliasing rules is illegal. (Note that this is not unique to GNU Fortran; any Fortran compiler that supports Cray pointers will "incorrectly" optimize code with illegal aliasing.) There are a number of restrictions on the attributes that can be applied to Cray pointers and pointees. Pointees may not have the `ALLOCATABLE', `INTENT', `OPTIONAL', `DUMMY', `TARGET', `INTRINSIC', or `POINTER' attributes. Pointers may not have the `DIMENSION', `POINTER', `TARGET', `ALLOCATABLE', `EXTERNAL', or `INTRINSIC' attributes. Pointees may not occur in more than one pointer statement. A pointee cannot be a pointer. Pointees cannot occur in equivalence, common, or data statements. A Cray pointer may also point to a function or a subroutine. For example, the following excerpt is valid: implicit none external sub pointer (subptr,subpte) external subpte subptr = loc(sub) call subpte() [...] subroutine sub [...] end subroutine sub A pointer may be modified during the course of a program, and this will change the location to which the pointee refers. However, when pointees are passed as arguments, they are treated as ordinary variables in the invoked function. Subsequent changes to the pointer will not change the base address of the array that was passed.  File: gfortran.info, Node: CONVERT specifier, Next: OpenMP, Prev: Cray pointers, Up: Extensions implemented in GNU Fortran 5.1.14 `CONVERT' specifier -------------------------- GNU Fortran allows the conversion of unformatted data between little- and big-endian representation to facilitate moving of data between different systems. The conversion can be indicated with the `CONVERT' specifier on the `OPEN' statement. *Note GFORTRAN_CONVERT_UNIT::, for an alternative way of specifying the data format via an environment variable. Valid values for `CONVERT' are: `CONVERT='NATIVE'' Use the native format. This is the default. `CONVERT='SWAP'' Swap between little- and big-endian. `CONVERT='LITTLE_ENDIAN'' Use the little-endian representation for unformatted files. `CONVERT='BIG_ENDIAN'' Use the big-endian representation for unformatted files. Using the option could look like this: open(file='big.dat',form='unformatted',access='sequential', & convert='big_endian') The value of the conversion can be queried by using `INQUIRE(CONVERT=ch)'. The values returned are `'BIG_ENDIAN'' and `'LITTLE_ENDIAN''. `CONVERT' works between big- and little-endian for `INTEGER' values of all supported kinds and for `REAL' on IEEE systems of kinds 4 and 8. Conversion between different "extended double" types on different architectures such as m68k and x86_64, which GNU Fortran supports as `REAL(KIND=10)' and `REAL(KIND=16)', will probably not work. _Note that the values specified via the GFORTRAN_CONVERT_UNIT environment variable will override the CONVERT specifier in the open statement_. This is to give control over data formats to users who do not have the source code of their program available. Using anything but the native representation for unformatted data carries a significant speed overhead. If speed in this area matters to you, it is best if you use this only for data that needs to be portable.  File: gfortran.info, Node: OpenMP, Next: Argument list functions, Prev: CONVERT specifier, Up: Extensions implemented in GNU Fortran 5.1.15 OpenMP ------------- OpenMP (Open Multi-Processing) is an application programming interface (API) that supports multi-platform shared memory multiprocessing programming in C/C++ and Fortran on many architectures, including Unix and Microsoft Windows platforms. It consists of a set of compiler directives, library routines, and environment variables that influence run-time behavior. GNU Fortran strives to be compatible to the OpenMP Application Program Interface v2.5 (http://www.openmp.org/drupal/mp-documents/spec25.pdf). To enable the processing of the OpenMP directive `!$omp' in free-form source code; the `c$omp', `*$omp' and `!$omp' directives in fixed form; the `!$' conditional compilation sentinels in free form; and the `c$', `*$' and `!$' sentinels in fixed form, `gfortran' needs to be invoked with the `-fopenmp'. This also arranges for automatic linking of the GNU OpenMP runtime library *note libgomp: (libgomp)Top. The OpenMP Fortran runtime library routines are provided both in a form of a Fortran 90 module named `omp_lib' and in a form of a Fortran `include' file named `omp_lib.h'. An example of a parallelized loop taken from Appendix A.1 of the OpenMP Application Program Interface v2.5: SUBROUTINE A1(N, A, B) INTEGER I, N REAL B(N), A(N) !$OMP PARALLEL DO !I is private by default DO I=2,N B(I) = (A(I) + A(I-1)) / 2.0 ENDDO !$OMP END PARALLEL DO END SUBROUTINE A1 Please note: * `-fopenmp' implies `-frecursive', i.e. all local arrays will be allocated on the stack. When porting existing code to OpenMP, this may lead to surprising results, especially to segmentation faults if the stacksize is limited. * On glibc-based systems, OpenMP enabled applications can not be statically linked due to limitations of the underlying pthreads-implementation. It might be possible to get a working solution if `-Wl,--whole-archive -lpthread -Wl,--no-whole-archive' is added to the command line. However, this is not supported by `gcc' and thus not recommended.  File: gfortran.info, Node: Argument list functions, Prev: OpenMP, Up: Extensions implemented in GNU Fortran 5.1.16 Argument list functions `%VAL', `%REF' and `%LOC' -------------------------------------------------------- GNU Fortran supports argument list functions `%VAL', `%REF' and `%LOC' statements, for backward compatibility with g77. It is recommended that these should be used only for code that is accessing facilities outside of GNU Fortran, such as operating system or windowing facilities. It is best to constrain such uses to isolated portions of a program-portions that deal specifically and exclusively with low-level, system-dependent facilities. Such portions might well provide a portable interface for use by the program as a whole, but are themselves not portable, and should be thoroughly tested each time they are rebuilt using a new compiler or version of a compiler. `%VAL' passes a scalar argument by value, `%REF' passes it by reference and `%LOC' passes its memory location. Since gfortran already passes scalar arguments by reference, `%REF' is in effect a do-nothing. `%LOC' has the same effect as a fortran pointer. An example of passing an argument by value to a C subroutine foo.: C C prototype void foo_ (float x); C external foo real*4 x x = 3.14159 call foo (%VAL (x)) end For details refer to the g77 manual `http://gcc.gnu.org/onlinedocs/gcc-3.4.6/g77/index.html#Top'. Also, the gfortran testsuite c_by_val.f and its partner c_by_val.c are worth a look.  File: gfortran.info, Node: Extensions not implemented in GNU Fortran, Prev: Extensions implemented in GNU Fortran, Up: Extensions 5.2 Extensions not implemented in GNU Fortran ============================================= The long history of the Fortran language, its wide use and broad userbase, the large number of different compiler vendors and the lack of some features crucial to users in the first standards have lead to the existence of an important number of extensions to the language. While some of the most useful or popular extensions are supported by the GNU Fortran compiler, not all existing extensions are supported. This section aims at listing these extensions and offering advice on how best make code that uses them running with the GNU Fortran compiler. * Menu: * STRUCTURE and RECORD:: * ENCODE and DECODE statements::  File: gfortran.info, Node: STRUCTURE and RECORD, Next: ENCODE and DECODE statements, Up: Extensions not implemented in GNU Fortran 5.2.1 `STRUCTURE' and `RECORD' ------------------------------ Structures are user-defined aggregate data types; this functionality was standardized in Fortran 90 with an different syntax, under the name of "derived types". Here is an example of code using the non portable structure syntax: ! Declaring a structure named ``item'' and containing three fields: ! an integer ID, an description string and a floating-point price. STRUCTURE /item/ INTEGER id CHARACTER(LEN=200) description REAL price END STRUCTURE ! Define two variables, an single record of type ``item'' ! named ``pear'', and an array of items named ``store_catalog'' RECORD /item/ pear, store_catalog(100) ! We can directly access the fields of both variables pear.id = 92316 pear.description = "juicy D'Anjou pear" pear.price = 0.15 store_catalog(7).id = 7831 store_catalog(7).description = "milk bottle" store_catalog(7).price = 1.2 ! We can also manipulates the whole structure store_catalog(12) = pear print *, store_catalog(12) This code can easily be rewritten in the Fortran 90 syntax as following: ! ``STRUCTURE /name/ ... END STRUCTURE'' becomes ! ``TYPE name ... END TYPE'' TYPE item INTEGER id CHARACTER(LEN=200) description REAL price END TYPE ! ``RECORD /name/ variable'' becomes ``TYPE(name) variable'' TYPE(item) pear, store_catalog(100) ! Instead of using a dot (.) to access fields of a record, the ! standard syntax uses a percent sign (%) pear%id = 92316 pear%description = "juicy D'Anjou pear" pear%price = 0.15 store_catalog(7)%id = 7831 store_catalog(7)%description = "milk bottle" store_catalog(7)%price = 1.2 ! Assignments of a whole variable don't change store_catalog(12) = pear print *, store_catalog(12)  File: gfortran.info, Node: ENCODE and DECODE statements, Prev: STRUCTURE and RECORD, Up: Extensions not implemented in GNU Fortran 5.2.2 `ENCODE' and `DECODE' statements -------------------------------------- GNU Fortran doesn't support the `ENCODE' and `DECODE' statements. These statements are best replaced by `READ' and `WRITE' statements involving internal files (`CHARACTER' variables and arrays), which have been part of the Fortran standard since Fortran 77. For example, replace a code fragment like INTEGER*1 LINE(80) REAL A, B, C c ... Code that sets LINE DECODE (80, 9000, LINE) A, B, C 9000 FORMAT (1X, 3(F10.5)) with the following: CHARACTER(LEN=80) LINE REAL A, B, C c ... Code that sets LINE READ (UNIT=LINE, FMT=9000) A, B, C 9000 FORMAT (1X, 3(F10.5)) Similarly, replace a code fragment like INTEGER*1 LINE(80) REAL A, B, C c ... Code that sets A, B and C ENCODE (80, 9000, LINE) A, B, C 9000 FORMAT (1X, 'OUTPUT IS ', 3(F10.5)) with the following: INTEGER*1 LINE(80) REAL A, B, C c ... Code that sets A, B and C WRITE (UNIT=LINE, FMT=9000) A, B, C 9000 FORMAT (1X, 'OUTPUT IS ', 3(F10.5))  File: gfortran.info, Node: Intrinsic Procedures, Next: Intrinsic Modules, Prev: Extensions, Up: Top 6 Intrinsic Procedures ********************** * Menu: * Introduction: Introduction to Intrinsics * `ABORT': ABORT, Abort the program * `ABS': ABS, Absolute value * `ACCESS': ACCESS, Checks file access modes * `ACHAR': ACHAR, Character in ASCII collating sequence * `ACOS': ACOS, Arccosine function * `ACOSH': ACOSH, Hyperbolic arccosine function * `ADJUSTL': ADJUSTL, Left adjust a string * `ADJUSTR': ADJUSTR, Right adjust a string * `AIMAG': AIMAG, Imaginary part of complex number * `AINT': AINT, Truncate to a whole number * `ALARM': ALARM, Set an alarm clock * `ALL': ALL, Determine if all values are true * `ALLOCATED': ALLOCATED, Status of allocatable entity * `AND': AND, Bitwise logical AND * `ANINT': ANINT, Nearest whole number * `ANY': ANY, Determine if any values are true * `ASIN': ASIN, Arcsine function * `ASINH': ASINH, Hyperbolic arcsine function * `ASSOCIATED': ASSOCIATED, Status of a pointer or pointer/target pair * `ATAN': ATAN, Arctangent function * `ATAN2': ATAN2, Arctangent function * `ATANH': ATANH, Hyperbolic arctangent function * `BESJ0': BESJ0, Bessel function of the first kind of order 0 * `BESJ1': BESJ1, Bessel function of the first kind of order 1 * `BESJN': BESJN, Bessel function of the first kind * `BESY0': BESY0, Bessel function of the second kind of order 0 * `BESY1': BESY1, Bessel function of the second kind of order 1 * `BESYN': BESYN, Bessel function of the second kind * `BIT_SIZE': BIT_SIZE, Bit size inquiry function * `BTEST': BTEST, Bit test function * `C_ASSOCIATED': C_ASSOCIATED, Status of a C pointer * `C_F_POINTER': C_F_POINTER, Convert C into Fortran pointer * `C_F_PROCPOINTER': C_F_PROCPOINTER, Convert C into Fortran procedure pointer * `C_FUNLOC': C_FUNLOC, Obtain the C address of a procedure * `C_LOC': C_LOC, Obtain the C address of an object * `CEILING': CEILING, Integer ceiling function * `CHAR': CHAR, Integer-to-character conversion function * `CHDIR': CHDIR, Change working directory * `CHMOD': CHMOD, Change access permissions of files * `CMPLX': CMPLX, Complex conversion function * `COMMAND_ARGUMENT_COUNT': COMMAND_ARGUMENT_COUNT, Get number of command line arguments * `COMPLEX': COMPLEX, Complex conversion function * `CONJG': CONJG, Complex conjugate function * `COS': COS, Cosine function * `COSH': COSH, Hyperbolic cosine function * `COUNT': COUNT, Count occurrences of TRUE in an array * `CPU_TIME': CPU_TIME, CPU time subroutine * `CSHIFT': CSHIFT, Circular shift elements of an array * `CTIME': CTIME, Subroutine (or function) to convert a time into a string * `DATE_AND_TIME': DATE_AND_TIME, Date and time subroutine * `DBLE': DBLE, Double precision conversion function * `DCMPLX': DCMPLX, Double complex conversion function * `DFLOAT': DFLOAT, Double precision conversion function * `DIGITS': DIGITS, Significant digits function * `DIM': DIM, Positive difference * `DOT_PRODUCT': DOT_PRODUCT, Dot product function * `DPROD': DPROD, Double product function * `DREAL': DREAL, Double real part function * `DTIME': DTIME, Execution time subroutine (or function) * `EOSHIFT': EOSHIFT, End-off shift elements of an array * `EPSILON': EPSILON, Epsilon function * `ERF': ERF, Error function * `ERFC': ERFC, Complementary error function * `ETIME': ETIME, Execution time subroutine (or function) * `EXIT': EXIT, Exit the program with status. * `EXP': EXP, Exponential function * `EXPONENT': EXPONENT, Exponent function * `FDATE': FDATE, Subroutine (or function) to get the current time as a string * `FGET': FGET, Read a single character in stream mode from stdin * `FGETC': FGETC, Read a single character in stream mode * `FLOAT': FLOAT, Convert integer to default real * `FLOOR': FLOOR, Integer floor function * `FLUSH': FLUSH, Flush I/O unit(s) * `FNUM': FNUM, File number function * `FPUT': FPUT, Write a single character in stream mode to stdout * `FPUTC': FPUTC, Write a single character in stream mode * `FRACTION': FRACTION, Fractional part of the model representation * `FREE': FREE, Memory de-allocation subroutine * `FSEEK': FSEEK, Low level file positioning subroutine * `FSTAT': FSTAT, Get file status * `FTELL': FTELL, Current stream position * `GAMMA': GAMMA, Gamma function * `GERROR': GERROR, Get last system error message * `GETARG': GETARG, Get command line arguments * `GET_COMMAND': GET_COMMAND, Get the entire command line * `GET_COMMAND_ARGUMENT': GET_COMMAND_ARGUMENT, Get command line arguments * `GETCWD': GETCWD, Get current working directory * `GETENV': GETENV, Get an environmental variable * `GET_ENVIRONMENT_VARIABLE': GET_ENVIRONMENT_VARIABLE, Get an environmental variable * `GETGID': GETGID, Group ID function * `GETLOG': GETLOG, Get login name * `GETPID': GETPID, Process ID function * `GETUID': GETUID, User ID function * `GMTIME': GMTIME, Convert time to GMT info * `HOSTNM': HOSTNM, Get system host name * `HUGE': HUGE, Largest number of a kind * `IACHAR': IACHAR, Code in ASCII collating sequence * `IAND': IAND, Bitwise logical and * `IARGC': IARGC, Get the number of command line arguments * `IBCLR': IBCLR, Clear bit * `IBITS': IBITS, Bit extraction * `IBSET': IBSET, Set bit * `ICHAR': ICHAR, Character-to-integer conversion function * `IDATE': IDATE, Current local time (day/month/year) * `IEOR': IEOR, Bitwise logical exclusive or * `IERRNO': IERRNO, Function to get the last system error number * `INDEX': INDEX intrinsic, Position of a substring within a string * `INT': INT, Convert to integer type * `INT2': INT2, Convert to 16-bit integer type * `INT8': INT8, Convert to 64-bit integer type * `IOR': IOR, Bitwise logical or * `IRAND': IRAND, Integer pseudo-random number * `IS_IOSTAT_END': IS_IOSTAT_END, Test for end-of-file value * `IS_IOSTAT_EOR': IS_IOSTAT_EOR, Test for end-of-record value * `ISATTY': ISATTY, Whether a unit is a terminal device * `ISHFT': ISHFT, Shift bits * `ISHFTC': ISHFTC, Shift bits circularly * `ISNAN': ISNAN, Tests for a NaN * `ITIME': ITIME, Current local time (hour/minutes/seconds) * `KILL': KILL, Send a signal to a process * `KIND': KIND, Kind of an entity * `LBOUND': LBOUND, Lower dimension bounds of an array * `LEN': LEN, Length of a character entity * `LEN_TRIM': LEN_TRIM, Length of a character entity without trailing blank characters * `LGAMMA': LGAMMA, Logarithm of the Gamma function * `LGE': LGE, Lexical greater than or equal * `LGT': LGT, Lexical greater than * `LINK': LINK, Create a hard link * `LLE': LLE, Lexical less than or equal * `LLT': LLT, Lexical less than * `LNBLNK': LNBLNK, Index of the last non-blank character in a string * `LOC': LOC, Returns the address of a variable * `LOG': LOG, Logarithm function * `LOG10': LOG10, Base 10 logarithm function * `LOGICAL': LOGICAL, Convert to logical type * `LONG': LONG, Convert to integer type * `LSHIFT': LSHIFT, Left shift bits * `LSTAT': LSTAT, Get file status * `LTIME': LTIME, Convert time to local time info * `MALLOC': MALLOC, Dynamic memory allocation function * `MATMUL': MATMUL, matrix multiplication * `MAX': MAX, Maximum value of an argument list * `MAXEXPONENT': MAXEXPONENT, Maximum exponent of a real kind * `MAXLOC': MAXLOC, Location of the maximum value within an array * `MAXVAL': MAXVAL, Maximum value of an array * `MCLOCK': MCLOCK, Time function * `MCLOCK8': MCLOCK8, Time function (64-bit) * `MERGE': MERGE, Merge arrays * `MIN': MIN, Minimum value of an argument list * `MINEXPONENT': MINEXPONENT, Minimum exponent of a real kind * `MINLOC': MINLOC, Location of the minimum value within an array * `MINVAL': MINVAL, Minimum value of an array * `MOD': MOD, Remainder function * `MODULO': MODULO, Modulo function * `MOVE_ALLOC': MOVE_ALLOC, Move allocation from one object to another * `MVBITS': MVBITS, Move bits from one integer to another * `NEAREST': NEAREST, Nearest representable number * `NEW_LINE': NEW_LINE, New line character * `NINT': NINT, Nearest whole number * `NOT': NOT, Logical negation * `NULL': NULL, Function that returns an disassociated pointer * `OR': OR, Bitwise logical OR * `PACK': PACK, Pack an array into an array of rank one * `PERROR': PERROR, Print system error message * `PRECISION': PRECISION, Decimal precision of a real kind * `PRESENT': PRESENT, Determine whether an optional dummy argument is specified * `PRODUCT': PRODUCT, Product of array elements * `RADIX': RADIX, Base of a data model * `RANDOM_NUMBER': RANDOM_NUMBER, Pseudo-random number * `RANDOM_SEED': RANDOM_SEED, Initialize a pseudo-random number sequence * `RAND': RAND, Real pseudo-random number * `RANGE': RANGE, Decimal exponent range of a real kind * `RAN': RAN, Real pseudo-random number * `REAL': REAL, Convert to real type * `RENAME': RENAME, Rename a file * `REPEAT': REPEAT, Repeated string concatenation * `RESHAPE': RESHAPE, Function to reshape an array * `RRSPACING': RRSPACING, Reciprocal of the relative spacing * `RSHIFT': RSHIFT, Right shift bits * `SCALE': SCALE, Scale a real value * `SCAN': SCAN, Scan a string for the presence of a set of characters * `SECNDS': SECNDS, Time function * `SECOND': SECOND, CPU time function * `SELECTED_INT_KIND': SELECTED_INT_KIND, Choose integer kind * `SELECTED_REAL_KIND': SELECTED_REAL_KIND, Choose real kind * `SET_EXPONENT': SET_EXPONENT, Set the exponent of the model * `SHAPE': SHAPE, Determine the shape of an array * `SIGN': SIGN, Sign copying function * `SIGNAL': SIGNAL, Signal handling subroutine (or function) * `SIN': SIN, Sine function * `SINH': SINH, Hyperbolic sine function * `SIZE': SIZE, Function to determine the size of an array * `SIZEOF': SIZEOF, Determine the size in bytes of an expression * `SLEEP': SLEEP, Sleep for the specified number of seconds * `SNGL': SNGL, Convert double precision real to default real * `SPACING': SPACING, Smallest distance between two numbers of a given type * `SPREAD': SPREAD, Add a dimension to an array * `SQRT': SQRT, Square-root function * `SRAND': SRAND, Reinitialize the random number generator * `STAT': STAT, Get file status * `SUM': SUM, Sum of array elements * `SYMLNK': SYMLNK, Create a symbolic link * `SYSTEM': SYSTEM, Execute a shell command * `SYSTEM_CLOCK': SYSTEM_CLOCK, Time function * `TAN': TAN, Tangent function * `TANH': TANH, Hyperbolic tangent function * `TIME': TIME, Time function * `TIME8': TIME8, Time function (64-bit) * `TINY': TINY, Smallest positive number of a real kind * `TRANSFER': TRANSFER, Transfer bit patterns * `TRANSPOSE': TRANSPOSE, Transpose an array of rank two * `TRIM': TRIM, Remove trailing blank characters of a string * `TTYNAM': TTYNAM, Get the name of a terminal device. * `UBOUND': UBOUND, Upper dimension bounds of an array * `UMASK': UMASK, Set the file creation mask * `UNLINK': UNLINK, Remove a file from the file system * `UNPACK': UNPACK, Unpack an array of rank one into an array * `VERIFY': VERIFY, Scan a string for the absence of a set of characters * `XOR': XOR, Bitwise logical exclusive or  File: gfortran.info, Node: Introduction to Intrinsics, Next: ABORT, Up: Intrinsic Procedures 6.1 Introduction to intrinsic procedures ======================================== The intrinsic procedures provided by GNU Fortran include all of the intrinsic procedures required by the Fortran 95 standard, a set of intrinsic procedures for backwards compatibility with G77, and a small selection of intrinsic procedures from the Fortran 2003 standard. Any conflict between a description here and a description in either the Fortran 95 standard or the Fortran 2003 standard is unintentional, and the standard(s) should be considered authoritative. The enumeration of the `KIND' type parameter is processor defined in the Fortran 95 standard. GNU Fortran defines the default integer type and default real type by `INTEGER(KIND=4)' and `REAL(KIND=4)', respectively. The standard mandates that both data types shall have another kind, which have more precision. On typical target architectures supported by `gfortran', this kind type parameter is `KIND=8'. Hence, `REAL(KIND=8)' and `DOUBLE PRECISION' are equivalent. In the description of generic intrinsic procedures, the kind type parameter will be specified by `KIND=*', and in the description of specific names for an intrinsic procedure the kind type parameter will be explicitly given (e.g., `REAL(KIND=4)' or `REAL(KIND=8)'). Finally, for brevity the optional `KIND=' syntax will be omitted. Many of the intrinsic procedures take one or more optional arguments. This document follows the convention used in the Fortran 95 standard, and denotes such arguments by square brackets. GNU Fortran offers the `-std=f95' and `-std=gnu' options, which can be used to restrict the set of intrinsic procedures to a given standard. By default, `gfortran' sets the `-std=gnu' option, and so all intrinsic procedures described here are accepted. There is one caveat. For a select group of intrinsic procedures, `g77' implemented both a function and a subroutine. Both classes have been implemented in `gfortran' for backwards compatibility with `g77'. It is noted here that these functions and subroutines cannot be intermixed in a given subprogram. In the descriptions that follow, the applicable standard for each intrinsic procedure is noted.  File: gfortran.info, Node: ABORT, Next: ABS, Prev: Introduction to Intrinsics, Up: Intrinsic Procedures 6.2 `ABORT' -- Abort the program ================================ _Description_: `ABORT' causes immediate termination of the program. On operating systems that support a core dump, `ABORT' will produce a core dump, which is suitable for debugging purposes. _Standard_: GNU extension _Class_: Subroutine _Syntax_: `CALL ABORT' _Return value_: Does not return. _Example_: program test_abort integer :: i = 1, j = 2 if (i /= j) call abort end program test_abort _See also_: *note EXIT::, *note KILL::  File: gfortran.info, Node: ABS, Next: ACCESS, Prev: ABORT, Up: Intrinsic Procedures 6.3 `ABS' -- Absolute value =========================== _Description_: `ABS(X)' computes the absolute value of `X'. _Standard_: F77 and later, has overloads that are GNU extensions _Class_: Elemental function _Syntax_: `RESULT = ABS(X)' _Arguments_: X The type of the argument shall be an `INTEGER(*)', `REAL(*)', or `COMPLEX(*)'. _Return value_: The return value is of the same type and kind as the argument except the return value is `REAL(*)' for a `COMPLEX(*)' argument. _Example_: program test_abs integer :: i = -1 real :: x = -1.e0 complex :: z = (-1.e0,0.e0) i = abs(i) x = abs(x) x = abs(z) end program test_abs _Specific names_: Name Argument Return type Standard `CABS(Z)' `COMPLEX(4) `REAL(4)' F77 and later Z' `DABS(X)' `REAL(8) `REAL(8)' F77 and later X' `IABS(I)' `INTEGER(4) `INTEGER(4)' F77 and later I' `ZABS(Z)' `COMPLEX(8) `COMPLEX(8)' GNU extension Z' `CDABS(Z)' `COMPLEX(8) `COMPLEX(8)' GNU extension Z'  File: gfortran.info, Node: ACCESS, Next: ACHAR, Prev: ABS, Up: Intrinsic Procedures 6.4 `ACCESS' -- Checks file access modes ======================================== _Description_: `ACCESS(NAME, MODE)' checks whether the file NAME exists, is readable, writable or executable. Except for the executable check, `ACCESS' can be replaced by Fortran 95's `INQUIRE'. _Standard_: GNU extension _Class_: Inquiry function _Syntax_: `RESULT = ACCESS(NAME, MODE)' _Arguments_: NAME Scalar `CHARACTER' with the file name. Tailing blank are ignored unless the character `achar(0)' is present, then all characters up to and excluding `achar(0)' are used as file name. MODE Scalar `CHARACTER' with the file access mode, may be any concatenation of `"r"' (readable), `"w"' (writable) and `"x"' (executable), or `" "' to check for existence. _Return value_: Returns a scalar `INTEGER', which is `0' if the file is accessible in the given mode; otherwise or if an invalid argument has been given for `MODE' the value `1' is returned. _Example_: program access_test implicit none character(len=*), parameter :: file = 'test.dat' character(len=*), parameter :: file2 = 'test.dat '//achar(0) if(access(file,' ') == 0) print *, trim(file),' is exists' if(access(file,'r') == 0) print *, trim(file),' is readable' if(access(file,'w') == 0) print *, trim(file),' is writable' if(access(file,'x') == 0) print *, trim(file),' is executable' if(access(file2,'rwx') == 0) & print *, trim(file2),' is readable, writable and executable' end program access_test _Specific names_: _See also_:  File: gfortran.info, Node: ACHAR, Next: ACOS, Prev: ACCESS, Up: Intrinsic Procedures 6.5 `ACHAR' -- Character in ASCII collating sequence ==================================================== _Description_: `ACHAR(I)' returns the character located at position `I' in the ASCII collating sequence. _Standard_: F77 and later _Class_: Elemental function _Syntax_: `RESULT = ACHAR(I)' _Arguments_: I The type shall be `INTEGER(*)'. _Return value_: The return value is of type `CHARACTER' with a length of one. The kind type parameter is the same as `KIND('A')'. _Example_: program test_achar character c c = achar(32) end program test_achar _Note_: See *note ICHAR:: for a discussion of converting between numerical values and formatted string representations. _See also_: *note CHAR::, *note IACHAR::, *note ICHAR::  File: gfortran.info, Node: ACOS, Next: ACOSH, Prev: ACHAR, Up: Intrinsic Procedures 6.6 `ACOS' -- Arccosine function ================================ _Description_: `ACOS(X)' computes the arccosine of X (inverse of `COS(X)'). _Standard_: F77 and later _Class_: Elemental function _Syntax_: `RESULT = ACOS(X)' _Arguments_: X The type shall be `REAL(*)' with a magnitude that is less than one. _Return value_: The return value is of type `REAL(*)' and it lies in the range 0 \leq \acos(x) \leq \pi. The kind type parameter is the same as X. _Example_: program test_acos real(8) :: x = 0.866_8 x = acos(x) end program test_acos _Specific names_: Name Argument Return type Standard `DACOS(X)' `REAL(8) X' `REAL(8)' F77 and later _See also_: Inverse function: *note COS::  File: gfortran.info, Node: ACOSH, Next: ADJUSTL, Prev: ACOS, Up: Intrinsic Procedures 6.7 `ACOSH' -- Hyperbolic arccosine function ============================================ _Description_: `ACOSH(X)' computes the hyperbolic arccosine of X (inverse of `COSH(X)'). _Standard_: GNU extension _Class_: Elemental function _Syntax_: `RESULT = ACOSH(X)' _Arguments_: X The type shall be `REAL(*)' with a magnitude that is greater or equal to one. _Return value_: The return value is of type `REAL(*)' and it lies in the range 0 \leq \acosh (x) \leq \infty. _Example_: PROGRAM test_acosh REAL(8), DIMENSION(3) :: x = (/ 1.0, 2.0, 3.0 /) WRITE (*,*) ACOSH(x) END PROGRAM _Specific names_: Name Argument Return type Standard `DACOSH(X)' `REAL(8) X' `REAL(8)' GNU extension _See also_: Inverse function: *note COSH::  File: gfortran.info, Node: ADJUSTL, Next: ADJUSTR, Prev: ACOSH, Up: Intrinsic Procedures 6.8 `ADJUSTL' -- Left adjust a string ===================================== _Description_: `ADJUSTL(STR)' will left adjust a string by removing leading spaces. Spaces are inserted at the end of the string as needed. _Standard_: F95 and later _Class_: Elemental function _Syntax_: `RESULT = ADJUSTL(STR)' _Arguments_: STR The type shall be `CHARACTER'. _Return value_: The return value is of type `CHARACTER' where leading spaces are removed and the same number of spaces are inserted on the end of STR. _Example_: program test_adjustl character(len=20) :: str = ' gfortran' str = adjustl(str) print *, str end program test_adjustl _See also_: *note ADJUSTR::, *note TRIM::  File: gfortran.info, Node: ADJUSTR, Next: AIMAG, Prev: ADJUSTL, Up: Intrinsic Procedures 6.9 `ADJUSTR' -- Right adjust a string ====================================== _Description_: `ADJUSTR(STR)' will right adjust a string by removing trailing spaces. Spaces are inserted at the start of the string as needed. _Standard_: F95 and later _Class_: Elemental function _Syntax_: `RESULT = ADJUSTR(STR)' _Arguments_: STR The type shall be `CHARACTER'. _Return value_: The return value is of type `CHARACTER' where trailing spaces are removed and the same number of spaces are inserted at the start of STR. _Example_: program test_adjustr character(len=20) :: str = 'gfortran' str = adjustr(str) print *, str end program test_adjustr _See also_: *note ADJUSTL::, *note TRIM::  File: gfortran.info, Node: AIMAG, Next: AINT, Prev: ADJUSTR, Up: Intrinsic Procedures 6.10 `AIMAG' -- Imaginary part of complex number ================================================ _Description_: `AIMAG(Z)' yields the imaginary part of complex argument `Z'. The `IMAG(Z)' and `IMAGPART(Z)' intrinsic functions are provided for compatibility with `g77', and their use in new code is strongly discouraged. _Standard_: F77 and later, has overloads that are GNU extensions _Class_: Elemental function _Syntax_: `RESULT = AIMAG(Z)' _Arguments_: Z The type of the argument shall be `COMPLEX(*)'. _Return value_: The return value is of type real with the kind type parameter of the argument. _Example_: program test_aimag complex(4) z4 complex(8) z8 z4 = cmplx(1.e0_4, 0.e0_4) z8 = cmplx(0.e0_8, 1.e0_8) print *, aimag(z4), dimag(z8) end program test_aimag _Specific names_: Name Argument Return type Standard `DIMAG(Z)' `COMPLEX(8) `REAL(8)' GNU extension Z' `IMAG(Z)' `COMPLEX(*) `REAL(*)' GNU extension Z' `IMAGPART(Z)' `COMPLEX(*) `REAL(*)' GNU extension Z'  File: gfortran.info, Node: AINT, Next: ALARM, Prev: AIMAG, Up: Intrinsic Procedures 6.11 `AINT' -- Truncate to a whole number ========================================= _Description_: `AINT(X [, KIND])' truncates its argument to a whole number. _Standard_: F77 and later _Class_: Elemental function _Syntax_: `RESULT = AINT(X [, KIND])' _Arguments_: X The type of the argument shall be `REAL(*)'. KIND (Optional) An `INTEGER(*)' initialization expression indicating the kind parameter of the result. _Return value_: The return value is of type real with the kind type parameter of the argument if the optional KIND is absent; otherwise, the kind type parameter will be given by KIND. If the magnitude of X is less than one, then `AINT(X)' returns zero. If the magnitude is equal to or greater than one, then it returns the largest whole number that does not exceed its magnitude. The sign is the same as the sign of X. _Example_: program test_aint real(4) x4 real(8) x8 x4 = 1.234E0_4 x8 = 4.321_8 print *, aint(x4), dint(x8) x8 = aint(x4,8) end program test_aint _Specific names_: Name Argument Return type Standard `DINT(X)' `REAL(8) X' `REAL(8)' F77 and later  File: gfortran.info, Node: ALARM, Next: ALL, Prev: AINT, Up: Intrinsic Procedures 6.12 `ALARM' -- Execute a routine after a given delay ===================================================== _Description_: `ALARM(SECONDS, HANDLER [, STATUS])' causes external subroutine HANDLER to be executed after a delay of SECONDS by using `alarm(2)' to set up a signal and `signal(2)' to catch it. If STATUS is supplied, it will be returned with the number of seconds remaining until any previously scheduled alarm was due to be delivered, or zero if there was no previously scheduled alarm. _Standard_: GNU extension _Class_: Subroutine _Syntax_: `CALL ALARM(SECONDS, HANDLER [, STATUS])' _Arguments_: SECONDS The type of the argument shall be a scalar `INTEGER'. It is `INTENT(IN)'. HANDLER Signal handler (`INTEGER FUNCTION' or `SUBROUTINE') or dummy/global `INTEGER' scalar. The scalar values may be either `SIG_IGN=1' to ignore the alarm generated or `SIG_DFL=0' to set the default action. It is `INTENT(IN)'. STATUS (Optional) STATUS shall be a scalar variable of the default `INTEGER' kind. It is `INTENT(OUT)'. _Example_: program test_alarm external handler_print integer i call alarm (3, handler_print, i) print *, i call sleep(10) end program test_alarm This will cause the external routine HANDLER_PRINT to be called after 3 seconds.  File: gfortran.info, Node: ALL, Next: ALLOCATED, Prev: ALARM, Up: Intrinsic Procedures 6.13 `ALL' -- All values in MASK along DIM are true =================================================== _Description_: `ALL(MASK [, DIM])' determines if all the values are true in MASK in the array along dimension DIM. _Standard_: F95 and later _Class_: Transformational function _Syntax_: `RESULT = ALL(MASK [, DIM])' _Arguments_: MASK The type of the argument shall be `LOGICAL(*)' and it shall not be scalar. DIM (Optional) DIM shall be a scalar integer with a value that lies between one and the rank of MASK. _Return value_: `ALL(MASK)' returns a scalar value of type `LOGICAL(*)' where the kind type parameter is the same as the kind type parameter of MASK. If DIM is present, then `ALL(MASK, DIM)' returns an array with the rank of MASK minus 1. The shape is determined from the shape of MASK where the DIM dimension is elided. (A) `ALL(MASK)' is true if all elements of MASK are true. It also is true if MASK has zero size; otherwise, it is false. (B) If the rank of MASK is one, then `ALL(MASK,DIM)' is equivalent to `ALL(MASK)'. If the rank is greater than one, then `ALL(MASK,DIM)' is determined by applying `ALL' to the array sections. _Example_: program test_all logical l l = all((/.true., .true., .true./)) print *, l call section contains subroutine section integer a(2,3), b(2,3) a = 1 b = 1 b(2,2) = 2 print *, all(a .eq. b, 1) print *, all(a .eq. b, 2) end subroutine section end program test_all  File: gfortran.info, Node: ALLOCATED, Next: AND, Prev: ALL, Up: Intrinsic Procedures 6.14 `ALLOCATED' -- Status of an allocatable entity =================================================== _Description_: `ALLOCATED(X)' checks the status of whether X is allocated. _Standard_: F95 and later _Class_: Inquiry function _Syntax_: `RESULT = ALLOCATED(X)' _Arguments_: X The argument shall be an `ALLOCATABLE' array. _Return value_: The return value is a scalar `LOGICAL' with the default logical kind type parameter. If X is allocated, `ALLOCATED(X)' is `.TRUE.'; otherwise, it returns `.FALSE.' _Example_: program test_allocated integer :: i = 4 real(4), allocatable :: x(:) if (allocated(x) .eqv. .false.) allocate(x(i)) end program test_allocated  File: gfortran.info, Node: AND, Next: ANINT, Prev: ALLOCATED, Up: Intrinsic Procedures 6.15 `AND' -- Bitwise logical AND ================================= _Description_: Bitwise logical `AND'. This intrinsic routine is provided for backwards compatibility with GNU Fortran 77. For integer arguments, programmers should consider the use of the *note IAND:: intrinsic defined by the Fortran standard. _Standard_: GNU extension _Class_: Function _Syntax_: `RESULT = AND(I, J)' _Arguments_: I The type shall be either `INTEGER(*)' or `LOGICAL'. J The type shall be either `INTEGER(*)' or `LOGICAL'. _Return value_: The return type is either `INTEGER(*)' or `LOGICAL' after cross-promotion of the arguments. _Example_: PROGRAM test_and LOGICAL :: T = .TRUE., F = .FALSE. INTEGER :: a, b DATA a / Z'F' /, b / Z'3' / WRITE (*,*) AND(T, T), AND(T, F), AND(F, T), AND(F, F) WRITE (*,*) AND(a, b) END PROGRAM _See also_: F95 elemental function: *note IAND::  File: gfortran.info, Node: ANINT, Next: ANY, Prev: AND, Up: Intrinsic Procedures 6.16 `ANINT' -- Nearest whole number ==================================== _Description_: `ANINT(X [, KIND])' rounds its argument to the nearest whole number. _Standard_: F77 and later _Class_: Elemental function _Syntax_: `RESULT = ANINT(X [, KIND])' _Arguments_: X The type of the argument shall be `REAL(*)'. KIND (Optional) An `INTEGER(*)' initialization expression indicating the kind parameter of the result. _Return value_: The return value is of type real with the kind type parameter of the argument if the optional KIND is absent; otherwise, the kind type parameter will be given by KIND. If X is greater than zero, then `ANINT(X)' returns `AINT(X+0.5)'. If X is less than or equal to zero, then it returns `AINT(X-0.5)'. _Example_: program test_anint real(4) x4 real(8) x8 x4 = 1.234E0_4 x8 = 4.321_8 print *, anint(x4), dnint(x8) x8 = anint(x4,8) end program test_anint _Specific names_: Name Argument Return type Standard `DNINT(X)' `REAL(8) X' `REAL(8)' F77 and later  File: gfortran.info, Node: ANY, Next: ASIN, Prev: ANINT, Up: Intrinsic Procedures 6.17 `ANY' -- Any value in MASK along DIM is true ================================================= _Description_: `ANY(MASK [, DIM])' determines if any of the values in the logical array MASK along dimension DIM are `.TRUE.'. _Standard_: F95 and later _Class_: Transformational function _Syntax_: `RESULT = ANY(MASK [, DIM])' _Arguments_: MASK The type of the argument shall be `LOGICAL(*)' and it shall not be scalar. DIM (Optional) DIM shall be a scalar integer with a value that lies between one and the rank of MASK. _Return value_: `ANY(MASK)' returns a scalar value of type `LOGICAL(*)' where the kind type parameter is the same as the kind type parameter of MASK. If DIM is present, then `ANY(MASK, DIM)' returns an array with the rank of MASK minus 1. The shape is determined from the shape of MASK where the DIM dimension is elided. (A) `ANY(MASK)' is true if any element of MASK is true; otherwise, it is false. It also is false if MASK has zero size. (B) If the rank of MASK is one, then `ANY(MASK,DIM)' is equivalent to `ANY(MASK)'. If the rank is greater than one, then `ANY(MASK,DIM)' is determined by applying `ANY' to the array sections. _Example_: program test_any logical l l = any((/.true., .true., .true./)) print *, l call section contains subroutine section integer a(2,3), b(2,3) a = 1 b = 1 b(2,2) = 2 print *, any(a .eq. b, 1) print *, any(a .eq. b, 2) end subroutine section end program test_any  File: gfortran.info, Node: ASIN, Next: ASINH, Prev: ANY, Up: Intrinsic Procedures 6.18 `ASIN' -- Arcsine function =============================== _Description_: `ASIN(X)' computes the arcsine of its X (inverse of `SIN(X)'). _Standard_: F77 and later _Class_: Elemental function _Syntax_: `RESULT = ASIN(X)' _Arguments_: X The type shall be `REAL(*)', and a magnitude that is less than one. _Return value_: The return value is of type `REAL(*)' and it lies in the range -\pi / 2 \leq \asin (x) \leq \pi / 2. The kind type parameter is the same as X. _Example_: program test_asin real(8) :: x = 0.866_8 x = asin(x) end program test_asin _Specific names_: Name Argument Return type Standard `DASIN(X)' `REAL(8) X' `REAL(8)' F77 and later _See also_: Inverse function: *note SIN::  File: gfortran.info, Node: ASINH, Next: ASSOCIATED, Prev: ASIN, Up: Intrinsic Procedures 6.19 `ASINH' -- Hyperbolic arcsine function =========================================== _Description_: `ASINH(X)' computes the hyperbolic arcsine of X (inverse of `SINH(X)'). _Standard_: GNU extension _Class_: Elemental function _Syntax_: `RESULT = ASINH(X)' _Arguments_: X The type shall be `REAL(*)', with X a real number. _Return value_: The return value is of type `REAL(*)' and it lies in the range -\infty \leq \asinh (x) \leq \infty. _Example_: PROGRAM test_asinh REAL(8), DIMENSION(3) :: x = (/ -1.0, 0.0, 1.0 /) WRITE (*,*) ASINH(x) END PROGRAM _Specific names_: Name Argument Return type Standard `DASINH(X)' `REAL(8) X' `REAL(8)' GNU extension. _See also_: Inverse function: *note SINH::  File: gfortran.info, Node: ASSOCIATED, Next: ATAN, Prev: ASINH, Up: Intrinsic Procedures 6.20 `ASSOCIATED' -- Status of a pointer or pointer/target pair =============================================================== _Description_: `ASSOCIATED(PTR [, TGT])' determines the status of the pointer PTR or if PTR is associated with the target TGT. _Standard_: F95 and later _Class_: Inquiry function _Syntax_: `RESULT = ASSOCIATED(PTR [, TGT])' _Arguments_: PTR PTR shall have the `POINTER' attribute and it can be of any type. TGT (Optional) TGT shall be a `POINTER' or a `TARGET'. It must have the same type, kind type parameter, and array rank as PTR. The status of neither PTR nor TGT can be undefined. _Return value_: `ASSOCIATED(PTR)' returns a scalar value of type `LOGICAL(4)'. There are several cases: (A) If the optional TGT is not present, then `ASSOCIATED(PTR)' is true if PTR is associated with a target; otherwise, it returns false. (B) If TGT is present and a scalar target, the result is true if TGT is not a 0 sized storage sequence and the target associated with PTR occupies the same storage units. If PTR is disassociated, then the result is false. (C) If TGT is present and an array target, the result is true if TGT and PTR have the same shape, are not 0 sized arrays, are arrays whose elements are not 0 sized storage sequences, and TGT and PTR occupy the same storage units in array element order. As in case(B), the result is false, if PTR is disassociated. (D) If TGT is present and an scalar pointer, the result is true if target associated with PTR and the target associated with TGT are not 0 sized storage sequences and occupy the same storage units. The result is false, if either TGT or PTR is disassociated. (E) If TGT is present and an array pointer, the result is true if target associated with PTR and the target associated with TGT have the same shape, are not 0 sized arrays, are arrays whose elements are not 0 sized storage sequences, and TGT and PTR occupy the same storage units in array element order. The result is false, if either TGT or PTR is disassociated. _Example_: program test_associated implicit none real, target :: tgt(2) = (/1., 2./) real, pointer :: ptr(:) ptr => tgt if (associated(ptr) .eqv. .false.) call abort if (associated(ptr,tgt) .eqv. .false.) call abort end program test_associated _See also_: *note NULL::  File: gfortran.info, Node: ATAN, Next: ATAN2, Prev: ASSOCIATED, Up: Intrinsic Procedures 6.21 `ATAN' -- Arctangent function ================================== _Description_: `ATAN(X)' computes the arctangent of X. _Standard_: F77 and later _Class_: Elemental function _Syntax_: `RESULT = ATAN(X)' _Arguments_: X The type shall be `REAL(*)'. _Return value_: The return value is of type `REAL(*)' and it lies in the range - \pi / 2 \leq \atan (x) \leq \pi / 2. _Example_: program test_atan real(8) :: x = 2.866_8 x = atan(x) end program test_atan _Specific names_: Name Argument Return type Standard `DATAN(X)' `REAL(8) X' `REAL(8)' F77 and later _See also_: Inverse function: *note TAN::  File: gfortran.info, Node: ATAN2, Next: ATANH, Prev: ATAN, Up: Intrinsic Procedures 6.22 `ATAN2' -- Arctangent function =================================== _Description_: `ATAN2(Y,X)' computes the arctangent of the complex number X + i Y. _Standard_: F77 and later _Class_: Elemental function _Syntax_: `RESULT = ATAN2(Y,X)' _Arguments_: Y The type shall be `REAL(*)'. X The type and kind type parameter shall be the same as Y. If Y is zero, then X must be nonzero. _Return value_: The return value has the same type and kind type parameter as Y. It is the principal value of the complex number X + i Y. If X is nonzero, then it lies in the range -\pi \le \atan (x) \leq \pi. The sign is positive if Y is positive. If Y is zero, then the return value is zero if X is positive and \pi if X is negative. Finally, if X is zero, then the magnitude of the result is \pi/2. _Example_: program test_atan2 real(4) :: x = 1.e0_4, y = 0.5e0_4 x = atan2(y,x) end program test_atan2 _Specific names_: Name Argument Return type Standard `DATAN2(X)' `REAL(8) X' `REAL(8)' F77 and later  File: gfortran.info, Node: ATANH, Next: BESJ0, Prev: ATAN2, Up: Intrinsic Procedures 6.23 `ATANH' -- Hyperbolic arctangent function ============================================== _Description_: `ATANH(X)' computes the hyperbolic arctangent of X (inverse of `TANH(X)'). _Standard_: GNU extension _Class_: Elemental function _Syntax_: `RESULT = ATANH(X)' _Arguments_: X The type shall be `REAL(*)' with a magnitude that is less than or equal to one. _Return value_: The return value is of type `REAL(*)' and it lies in the range -\infty \leq \atanh(x) \leq \infty. _Example_: PROGRAM test_atanh REAL, DIMENSION(3) :: x = (/ -1.0, 0.0, 1.0 /) WRITE (*,*) ATANH(x) END PROGRAM _Specific names_: Name Argument Return type Standard `DATANH(X)' `REAL(8) X' `REAL(8)' GNU extension _See also_: Inverse function: *note TANH::  File: gfortran.info, Node: BESJ0, Next: BESJ1, Prev: ATANH, Up: Intrinsic Procedures 6.24 `BESJ0' -- Bessel function of the first kind of order 0 ============================================================ _Description_: `BESJ0(X)' computes the Bessel function of the first kind of order 0 of X. _Standard_: GNU extension _Class_: Elemental function _Syntax_: `RESULT = BESJ0(X)' _Arguments_: X The type shall be `REAL(*)', and it shall be scalar. _Return value_: The return value is of type `REAL(*)' and it lies in the range - 0.4027... \leq Bessel (0,x) \leq 1. _Example_: program test_besj0 real(8) :: x = 0.0_8 x = besj0(x) end program test_besj0 _Specific names_: Name Argument Return type Standard `DBESJ0(X)' `REAL(8) X' `REAL(8)' GNU extension  File: gfortran.info, Node: BESJ1, Next: BESJN, Prev: BESJ0, Up: Intrinsic Procedures 6.25 `BESJ1' -- Bessel function of the first kind of order 1 ============================================================ _Description_: `BESJ1(X)' computes the Bessel function of the first kind of order 1 of X. _Standard_: GNU extension _Class_: Elemental function _Syntax_: `RESULT = BESJ1(X)' _Arguments_: X The type shall be `REAL(*)', and it shall be scalar. _Return value_: The return value is of type `REAL(*)' and it lies in the range - 0.5818... \leq Bessel (0,x) \leq 0.5818 . _Example_: program test_besj1 real(8) :: x = 1.0_8 x = besj1(x) end program test_besj1 _Specific names_: Name Argument Return type Standard `DBESJ1(X)' `REAL(8) X' `REAL(8)' GNU extension  File: gfortran.info, Node: BESJN, Next: BESY0, Prev: BESJ1, Up: Intrinsic Procedures 6.26 `BESJN' -- Bessel function of the first kind ================================================= _Description_: `BESJN(N, X)' computes the Bessel function of the first kind of order N of X. If both arguments are arrays, their ranks and shapes shall conform. _Standard_: GNU extension _Class_: Elemental function _Syntax_: `RESULT = BESJN(N, X)' _Arguments_: N Shall be a scalar or an array of type `INTEGER(*)'. X Shall be a scalar or an array of type `REAL(*)'. _Return value_: The return value is a scalar of type `REAL(*)'. _Example_: program test_besjn real(8) :: x = 1.0_8 x = besjn(5,x) end program test_besjn _Specific names_: Name Argument Return type Standard `DBESJN(X)' `INTEGER(*) `REAL(8)' GNU extension N' `REAL(8) X'  File: gfortran.info, Node: BESY0, Next: BESY1, Prev: BESJN, Up: Intrinsic Procedures 6.27 `BESY0' -- Bessel function of the second kind of order 0 ============================================================= _Description_: `BESY0(X)' computes the Bessel function of the second kind of order 0 of X. _Standard_: GNU extension _Class_: Elemental function _Syntax_: `RESULT = BESY0(X)' _Arguments_: X The type shall be `REAL(*)', and it shall be scalar. _Return value_: The return value is a scalar of type `REAL(*)'. _Example_: program test_besy0 real(8) :: x = 0.0_8 x = besy0(x) end program test_besy0 _Specific names_: Name Argument Return type Standard `DBESY0(X)' `REAL(8) X' `REAL(8)' GNU extension  File: gfortran.info, Node: BESY1, Next: BESYN, Prev: BESY0, Up: Intrinsic Procedures 6.28 `BESY1' -- Bessel function of the second kind of order 1 ============================================================= _Description_: `BESY1(X)' computes the Bessel function of the second kind of order 1 of X. _Standard_: GNU extension _Class_: Elemental function _Syntax_: `RESULT = BESY1(X)' _Arguments_: X The type shall be `REAL(*)', and it shall be scalar. _Return value_: The return value is a scalar of type `REAL(*)'. _Example_: program test_besy1 real(8) :: x = 1.0_8 x = besy1(x) end program test_besy1 _Specific names_: Name Argument Return type Standard `DBESY1(X)' `REAL(8) X' `REAL(8)' GNU extension  File: gfortran.info, Node: BESYN, Next: BIT_SIZE, Prev: BESY1, Up: Intrinsic Procedures 6.29 `BESYN' -- Bessel function of the second kind ================================================== _Description_: `BESYN(N, X)' computes the Bessel function of the second kind of order N of X. If both arguments are arrays, their ranks and shapes shall conform. _Standard_: GNU extension _Class_: Elemental function _Syntax_: `RESULT = BESYN(N, X)' _Arguments_: N Shall be a scalar or an array of type `INTEGER(*)'. X Shall be a scalar or an array of type `REAL(*)'. _Return value_: The return value is a scalar of type `REAL(*)'. _Example_: program test_besyn real(8) :: x = 1.0_8 x = besyn(5,x) end program test_besyn _Specific names_: Name Argument Return type Standard `DBESYN(N,X)' `INTEGER(*) `REAL(8)' GNU extension N' `REAL(8) X'  File: gfortran.info, Node: BIT_SIZE, Next: BTEST, Prev: BESYN, Up: Intrinsic Procedures 6.30 `BIT_SIZE' -- Bit size inquiry function ============================================ _Description_: `BIT_SIZE(I)' returns the number of bits (integer precision plus sign bit) represented by the type of I. _Standard_: F95 and later _Class_: Inquiry function _Syntax_: `RESULT = BIT_SIZE(I)' _Arguments_: I The type shall be `INTEGER(*)'. _Return value_: The return value is of type `INTEGER(*)' _Example_: program test_bit_size integer :: i = 123 integer :: size size = bit_size(i) print *, size end program test_bit_size  File: gfortran.info, Node: BTEST, Next: C_ASSOCIATED, Prev: BIT_SIZE, Up: Intrinsic Procedures 6.31 `BTEST' -- Bit test function ================================= _Description_: `BTEST(I,POS)' returns logical `.TRUE.' if the bit at POS in I is set. _Standard_: F95 and later _Class_: Elemental function _Syntax_: `RESULT = BTEST(I, POS)' _Arguments_: I The type shall be `INTEGER(*)'. POS The type shall be `INTEGER(*)'. _Return value_: The return value is of type `LOGICAL' _Example_: program test_btest integer :: i = 32768 + 1024 + 64 integer :: pos logical :: bool do pos=0,16 bool = btest(i, pos) print *, pos, bool end do end program test_btest  File: gfortran.info, Node: C_ASSOCIATED, Next: C_F_POINTER, Prev: BTEST, Up: Intrinsic Procedures 6.32 `C_ASSOCIATED' -- Status of a C pointer ============================================ _Description_: `C_ASSOICATED(c_prt1[, c_ptr2])' determines the status of the C pointer C_PTR1 or if C_PTR1 is associated with the target C_PTR2. _Standard_: F2003 and later _Class_: Inquiry function _Syntax_: `RESULT = C_ASSOICATED(c_prt1[, c_ptr2])' _Arguments_: C_PTR1 Scalar of the type `C_PTR' or `C_FUNPTR'. C_PTR2 (Optional) Scalar of the same type as C_PTR1. _Return value_: The return value is of type `LOGICAL'; it is `.false.' if either C_PTR1 is a C NULL pointer or if C_PTR1 and C_PTR2 point to different addresses. _Example_: subroutine association_test(a,b) use iso_c_binding, only: c_associated, c_loc, c_ptr implicit none real, pointer :: a type(c_ptr) :: b if(c_associated(b, c_loc(a))) & stop 'b and a do not point to same target' end subroutine association_test _See also_: *note C_LOC::, *note C_FUNLOC::  File: gfortran.info, Node: C_FUNLOC, Next: C_LOC, Prev: C_F_PROCPOINTER, Up: Intrinsic Procedures 6.33 `C_FUNLOC' -- Obtain the C address of a procedure ====================================================== _Description_: `C_FUNLOC(x)' determines the C address of the argument. _Standard_: F2003 and later _Class_: Inquiry function _Syntax_: `RESULT = C_FUNLOC(x)' _Arguments_: X Interoperable function or pointer to such function. _Return value_: The return value is of type `C_FUNPTR' and contains the C address of the argument. _Example_: module x use iso_c_binding implicit none contains subroutine sub(a) bind(c) real(c_float) :: a a = sqrt(a)+5.0 end subroutine sub end module x program main use iso_c_binding use x implicit none interface subroutine my_routine(p) bind(c,name='myC_func') import :: c_funptr type(c_funptr), intent(in) :: p end subroutine end interface call my_routine(c_funloc(sub)) end program main _See also_: *note C_ASSOCIATED::, *note C_LOC::, *note C_F_POINTER::, *note C_F_PROCPOINTER::  File: gfortran.info, Node: C_F_PROCPOINTER, Next: C_FUNLOC, Prev: C_F_POINTER, Up: Intrinsic Procedures 6.34 `C_F_PROCPOINTER' -- Convert C into Fortran procedure pointer ================================================================== _Description_: `C_F_PROCPOINTER(cptr, fptr)' Assign the target of the C function pointer CPTR to the Fortran procedure pointer FPTR. Note: Due to the currently lacking support of procedure pointers in GNU Fortran this function is not fully operable. _Standard_: F2003 and later _Class_: Subroutine _Syntax_: `CALL C_F_PROCPOINTER(cptr, fptr)' _Arguments_: CPTR scalar of the type `C_FUNPTR'. It is `INTENT(IN)'. FPTR procedure pointer interoperable with CPTR. It is `INTENT(OUT)'. _Example_: program main use iso_c_binding implicit none abstract interface function func(a) import :: c_float real(c_float), intent(in) :: a real(c_float) :: func end function end interface interface function getIterFunc() bind(c,name="getIterFunc") import :: c_funptr type(c_funptr) :: getIterFunc end function end interface type(c_funptr) :: cfunptr procedure(func), pointer :: myFunc cfunptr = getIterFunc() call c_f_procpointer(cfunptr, myFunc) end program main _See also_: *note C_LOC::, *note C_F_POINTER::  File: gfortran.info, Node: C_F_POINTER, Next: C_F_PROCPOINTER, Prev: C_ASSOCIATED, Up: Intrinsic Procedures 6.35 `C_F_POINTER' -- Convert C into Fortran pointer ==================================================== _Description_: `C_F_POINTER(cptr, fptr[, shape])' Assign the target the C pointer CPTR to the Fortran pointer FPTR and specify its shape. _Standard_: F2003 and later _Class_: Subroutine _Syntax_: `CALL C_F_POINTER(cptr, fptr[, shape])' _Arguments_: CPTR scalar of the type `C_PTR'. It is `INTENT(IN)'. FPTR pointer interoperable with CPTR. It is `INTENT(OUT)'. SHAPE (Optional) Rank-one array of type `INTEGER' with `INTENT(IN)'. It shall be present if and only if FPTR is an array. The size must be equal to the rank of FPTR. _Example_: program main use iso_c_binding implicit none interface subroutine my_routine(p) bind(c,name='myC_func') import :: c_ptr type(c_ptr), intent(out) :: p end subroutine end interface type(c_ptr) :: cptr real,pointer :: a(:) call my_routine(cptr) call c_f_pointer(cptr, a, [12]) end program main _See also_: *note C_LOC::, *note C_F_PROCPOINTER::  File: gfortran.info, Node: C_LOC, Next: CEILING, Prev: C_FUNLOC, Up: Intrinsic Procedures 6.36 `C_LOC' -- Obtain the C address of an object ================================================= _Description_: `C_LOC(x)' determines the C address of the argument. _Standard_: F2003 and later _Class_: Inquiry function _Syntax_: `RESULT = C_LOC(x)' _Arguments_: X Associated scalar pointer or interoperable scalar or allocated allocatable variable with `TARGET' attribute. _Return value_: The return value is of type `C_PTR' and contains the C address of the argument. _Example_: subroutine association_test(a,b) use iso_c_binding, only: c_associated, c_loc, c_ptr implicit none real, pointer :: a type(c_ptr) :: b if(c_associated(b, c_loc(a))) & stop 'b and a do not point to same target' end subroutine association_test _See also_: *note C_ASSOCIATED::, *note C_FUNLOC::, *note C_F_POINTER::, *note C_F_PROCPOINTER::  File: gfortran.info, Node: CEILING, Next: CHAR, Prev: C_LOC, Up: Intrinsic Procedures 6.37 `CEILING' -- Integer ceiling function ========================================== _Description_: `CEILING(X)' returns the least integer greater than or equal to X. _Standard_: F95 and later _Class_: Elemental function _Syntax_: `RESULT = CEILING(X [, KIND])' _Arguments_: X The type shall be `REAL(*)'. KIND (Optional) An `INTEGER(*)' initialization expression indicating the kind parameter of the result. _Return value_: The return value is of type `INTEGER(KIND)' _Example_: program test_ceiling real :: x = 63.29 real :: y = -63.59 print *, ceiling(x) ! returns 64 print *, ceiling(y) ! returns -63 end program test_ceiling _See also_: *note FLOOR::, *note NINT::  File: gfortran.info, Node: CHAR, Next: CHDIR, Prev: CEILING, Up: Intrinsic Procedures 6.38 `CHAR' -- Character conversion function ============================================ _Description_: `CHAR(I [, KIND])' returns the character represented by the integer I. _Standard_: F77 and later _Class_: Elemental function _Syntax_: `RESULT = CHAR(I [, KIND])' _Arguments_: I The type shall be `INTEGER(*)'. KIND (Optional) An `INTEGER(*)' initialization expression indicating the kind parameter of the result. _Return value_: The return value is of type `CHARACTER(1)' _Example_: program test_char integer :: i = 74 character(1) :: c c = char(i) print *, i, c ! returns 'J' end program test_char _Note_: See *note ICHAR:: for a discussion of converting between numerical values and formatted string representations. _See also_: *note ACHAR::, *note IACHAR::, *note ICHAR::  File: gfortran.info, Node: CHDIR, Next: CHMOD, Prev: CHAR, Up: Intrinsic Procedures 6.39 `CHDIR' -- Change working directory ======================================== _Description_: Change current working directory to a specified path. This intrinsic is provided in both subroutine and function forms; however, only one form can be used in any given program unit. _Standard_: GNU extension _Class_: Subroutine, function _Syntax_: `CALL CHDIR(NAME [, STATUS])' `STATUS = CHDIR(NAME)' _Arguments_: NAME The type shall be `CHARACTER(*)' and shall specify a valid path within the file system. STATUS (Optional) `INTEGER' status flag of the default kind. Returns 0 on success, and a system specific and nonzero error code otherwise. _Example_: PROGRAM test_chdir CHARACTER(len=255) :: path CALL getcwd(path) WRITE(*,*) TRIM(path) CALL chdir("/tmp") CALL getcwd(path) WRITE(*,*) TRIM(path) END PROGRAM _See also_: *note GETCWD::  File: gfortran.info, Node: CHMOD, Next: CMPLX, Prev: CHDIR, Up: Intrinsic Procedures 6.40 `CHMOD' -- Change access permissions of files ================================================== _Description_: `CHMOD' changes the permissions of a file. This function invokes `/bin/chmod' and might therefore not work on all platforms. This intrinsic is provided in both subroutine and function forms; however, only one form can be used in any given program unit. _Standard_: GNU extension _Class_: Subroutine, function _Syntax_: `CALL CHMOD(NAME, MODE[, STATUS])' `STATUS = CHMOD(NAME, MODE)' _Arguments_: NAME Scalar `CHARACTER' with the file name. Trailing blanks are ignored unless the character `achar(0)' is present, then all characters up to and excluding `achar(0)' are used as the file name. MODE Scalar `CHARACTER' giving the file permission. MODE uses the same syntax as the MODE argument of `/bin/chmod'. STATUS (optional) scalar `INTEGER', which is `0' on success and nonzero otherwise. _Return value_: In either syntax, STATUS is set to `0' on success and nonzero otherwise. _Example_: `CHMOD' as subroutine program chmod_test implicit none integer :: status call chmod('test.dat','u+x',status) print *, 'Status: ', status end program chmod_test `CHMOD' as function: program chmod_test implicit none integer :: status status = chmod('test.dat','u+x') print *, 'Status: ', status end program chmod_test  File: gfortran.info, Node: CMPLX, Next: COMMAND_ARGUMENT_COUNT, Prev: CHMOD, Up: Intrinsic Procedures 6.41 `CMPLX' -- Complex conversion function =========================================== _Description_: `CMPLX(X [, Y [, KIND]])' returns a complex number where X is converted to the real component. If Y is present it is converted to the imaginary component. If Y is not present then the imaginary component is set to 0.0. If X is complex then Y must not be present. _Standard_: F77 and later _Class_: Elemental function _Syntax_: `RESULT = CMPLX(X [, Y [, KIND]])' _Arguments_: X The type may be `INTEGER(*)', `REAL(*)', or `COMPLEX(*)'. Y (Optional; only allowed if X is not `COMPLEX(*)'.) May be `INTEGER(*)' or `REAL(*)'. KIND (Optional) An `INTEGER(*)' initialization expression indicating the kind parameter of the result. _Return value_: The return value is of `COMPLEX' type, with a kind equal to KIND if it is specified. If KIND is not specified, the result is of the default `COMPLEX' kind, regardless of the kinds of X and Y. _Example_: program test_cmplx integer :: i = 42 real :: x = 3.14 complex :: z z = cmplx(i, x) print *, z, cmplx(x) end program test_cmplx _See also_: *note COMPLEX::  File: gfortran.info, Node: COMMAND_ARGUMENT_COUNT, Next: COMPLEX, Prev: CMPLX, Up: Intrinsic Procedures 6.42 `COMMAND_ARGUMENT_COUNT' -- Get number of command line arguments ===================================================================== _Description_: `COMMAND_ARGUMENT_COUNT()' returns the number of arguments passed on the command line when the containing program was invoked. _Standard_: F2003 _Class_: Inquiry function _Syntax_: `RESULT = COMMAND_ARGUMENT_COUNT()' _Arguments_: None _Return value_: The return value is of type `INTEGER(4)' _Example_: program test_command_argument_count integer :: count count = command_argument_count() print *, count end program test_command_argument_count _See also_: *note GET_COMMAND::, *note GET_COMMAND_ARGUMENT::  File: gfortran.info, Node: COMPLEX, Next: CONJG, Prev: COMMAND_ARGUMENT_COUNT, Up: Intrinsic Procedures 6.43 `COMPLEX' -- Complex conversion function ============================================= _Description_: `COMPLEX(X, Y)' returns a complex number where X is converted to the real component and Y is converted to the imaginary component. _Standard_: GNU extension _Class_: Elemental function _Syntax_: `RESULT = COMPLEX(X, Y)' _Arguments_: X The type may be `INTEGER(*)' or `REAL(*)'. Y The type may be `INTEGER(*)' or `REAL(*)'. _Return value_: If X and Y are both of `INTEGER' type, then the return value is of default `COMPLEX' type. If X and Y are of `REAL' type, or one is of `REAL' type and one is of `INTEGER' type, then the return value is of `COMPLEX' type with a kind equal to that of the `REAL' argument with the highest precision. _Example_: program test_complex integer :: i = 42 real :: x = 3.14 print *, complex(i, x) end program test_complex _See also_: *note CMPLX::  File: gfortran.info, Node: CONJG, Next: COS, Prev: COMPLEX, Up: Intrinsic Procedures 6.44 `CONJG' -- Complex conjugate function ========================================== _Description_: `CONJG(Z)' returns the conjugate of Z. If Z is `(x, y)' then the result is `(x, -y)' _Standard_: F77 and later, has overloads that are GNU extensions _Class_: Elemental function _Syntax_: `Z = CONJG(Z)' _Arguments_: Z The type shall be `COMPLEX(*)'. _Return value_: The return value is of type `COMPLEX(*)'. _Example_: program test_conjg complex :: z = (2.0, 3.0) complex(8) :: dz = (2.71_8, -3.14_8) z= conjg(z) print *, z dz = dconjg(dz) print *, dz end program test_conjg _Specific names_: Name Argument Return type Standard `DCONJG(Z)' `COMPLEX(8) `COMPLEX(8)' GNU extension Z'  File: gfortran.info, Node: COS, Next: COSH, Prev: CONJG, Up: Intrinsic Procedures 6.45 `COS' -- Cosine function ============================= _Description_: `COS(X)' computes the cosine of X. _Standard_: F77 and later, has overloads that are GNU extensions _Class_: Elemental function _Syntax_: `RESULT = COS(X)' _Arguments_: X The type shall be `REAL(*)' or `COMPLEX(*)'. _Return value_: The return value is of type `REAL(*)' and it lies in the range -1 \leq \cos (x) \leq 1. The kind type parameter is the same as X. _Example_: program test_cos real :: x = 0.0 x = cos(x) end program test_cos _Specific names_: Name Argument Return type Standard `DCOS(X)' `REAL(8) X' `REAL(8)' F77 and later `CCOS(X)' `COMPLEX(4) `COMPLEX(4)' F77 and later X' `ZCOS(X)' `COMPLEX(8) `COMPLEX(8)' GNU extension X' `CDCOS(X)' `COMPLEX(8) `COMPLEX(8)' GNU extension X' _See also_: Inverse function: *note ACOS::  File: gfortran.info, Node: COSH, Next: COUNT, Prev: COS, Up: Intrinsic Procedures 6.46 `COSH' -- Hyperbolic cosine function ========================================= _Description_: `COSH(X)' computes the hyperbolic cosine of X. _Standard_: F77 and later _Class_: Elemental function _Syntax_: `X = COSH(X)' _Arguments_: X The type shall be `REAL(*)'. _Return value_: The return value is of type `REAL(*)' and it is positive ( \cosh (x) \geq 0 . _Example_: program test_cosh real(8) :: x = 1.0_8 x = cosh(x) end program test_cosh _Specific names_: Name Argument Return type Standard `DCOSH(X)' `REAL(8) X' `REAL(8)' F77 and later _See also_: Inverse function: *note ACOSH::  File: gfortran.info, Node: COUNT, Next: CPU_TIME, Prev: COSH, Up: Intrinsic Procedures 6.47 `COUNT' -- Count function ============================== _Description_: `COUNT(MASK [, DIM [, KIND]])' counts the number of `.TRUE.' elements of MASK along the dimension of DIM. If DIM is omitted it is taken to be `1'. DIM is a scaler of type `INTEGER' in the range of 1 /leq DIM /leq n) where n is the rank of MASK. _Standard_: F95 and later _Class_: Transformational function _Syntax_: `RESULT = COUNT(MASK [, DIM [, KIND]])' _Arguments_: MASK The type shall be `LOGICAL'. DIM (Optional) The type shall be `INTEGER'. KIND (Optional) An `INTEGER' initialization expression indicating the kind parameter of the result. _Return value_: The return value is of type `INTEGER' and of kind KIND. If KIND is absent, the return value is of default integer kind. The result has a rank equal to that of MASK. _Example_: program test_count integer, dimension(2,3) :: a, b logical, dimension(2,3) :: mask a = reshape( (/ 1, 2, 3, 4, 5, 6 /), (/ 2, 3 /)) b = reshape( (/ 0, 7, 3, 4, 5, 8 /), (/ 2, 3 /)) print '(3i3)', a(1,:) print '(3i3)', a(2,:) print * print '(3i3)', b(1,:) print '(3i3)', b(2,:) print * mask = a.ne.b print '(3l3)', mask(1,:) print '(3l3)', mask(2,:) print * print '(3i3)', count(mask) print * print '(3i3)', count(mask, 1) print * print '(3i3)', count(mask, 2) end program test_count  File: gfortran.info, Node: CPU_TIME, Next: CSHIFT, Prev: COUNT, Up: Intrinsic Procedures 6.48 `CPU_TIME' -- CPU elapsed time in seconds ============================================== _Description_: Returns a `REAL(*)' value representing the elapsed CPU time in seconds. This is useful for testing segments of code to determine execution time. If a time source is available, time will be reported with microsecond resolution. If no time source is available, TIME is set to `-1.0'. Note that TIME may contain a, system dependent, arbitrary offset and may not start with `0.0'. For `CPU_TIME', the absolute value is meaningless, only differences between subsequent calls to this subroutine, as shown in the example below, should be used. _Standard_: F95 and later _Class_: Subroutine _Syntax_: `CALL CPU_TIME(TIME)' _Arguments_: TIME The type shall be `REAL(*)' with `INTENT(OUT)'. _Return value_: None _Example_: program test_cpu_time real :: start, finish call cpu_time(start) ! put code to test here call cpu_time(finish) print '("Time = ",f6.3," seconds.")',finish-start end program test_cpu_time _See also_: *note SYSTEM_CLOCK::, *note DATE_AND_TIME::  File: gfortran.info, Node: CSHIFT, Next: CTIME, Prev: CPU_TIME, Up: Intrinsic Procedures 6.49 `CSHIFT' -- Circular shift elements of an array ==================================================== _Description_: `CSHIFT(ARRAY, SHIFT [, DIM])' performs a circular shift on elements of ARRAY along the dimension of DIM. If DIM is omitted it is taken to be `1'. DIM is a scaler of type `INTEGER' in the range of 1 /leq DIM /leq n) where n is the rank of ARRAY. If the rank of ARRAY is one, then all elements of ARRAY are shifted by SHIFT places. If rank is greater than one, then all complete rank one sections of ARRAY along the given dimension are shifted. Elements shifted out one end of each rank one section are shifted back in the other end. _Standard_: F95 and later _Class_: Transformational function _Syntax_: `RESULT = CSHIFT(ARRAY, SHIFT [, DIM])' _Arguments_: ARRAY Shall be an array of any type. SHIFT The type shall be `INTEGER'. DIM The type shall be `INTEGER'. _Return value_: Returns an array of same type and rank as the ARRAY argument. _Example_: program test_cshift integer, dimension(3,3) :: a a = reshape( (/ 1, 2, 3, 4, 5, 6, 7, 8, 9 /), (/ 3, 3 /)) print '(3i3)', a(1,:) print '(3i3)', a(2,:) print '(3i3)', a(3,:) a = cshift(a, SHIFT=(/1, 2, -1/), DIM=2) print * print '(3i3)', a(1,:) print '(3i3)', a(2,:) print '(3i3)', a(3,:) end program test_cshift  File: gfortran.info, Node: CTIME, Next: DATE_AND_TIME, Prev: CSHIFT, Up: Intrinsic Procedures 6.50 `CTIME' -- Convert a time into a string ============================================ _Description_: `CTIME' converts a system time value, such as returned by `TIME8()', to a string of the form `Sat Aug 19 18:13:14 1995'. This intrinsic is provided in both subroutine and function forms; however, only one form can be used in any given program unit. _Standard_: GNU extension _Class_: Subroutine, function _Syntax_: `CALL CTIME(TIME, RESULT)'. `RESULT = CTIME(TIME)', (not recommended). _Arguments_: TIME The type shall be of type `INTEGER(KIND=8)'. RESULT The type shall be of type `CHARACTER'. _Return value_: The converted date and time as a string. _Example_: program test_ctime integer(8) :: i character(len=30) :: date i = time8() ! Do something, main part of the program call ctime(i,date) print *, 'Program was started on ', date end program test_ctime _See Also_: *note GMTIME::, *note LTIME::, *note TIME::, *note TIME8::  File: gfortran.info, Node: DATE_AND_TIME, Next: DBLE, Prev: CTIME, Up: Intrinsic Procedures 6.51 `DATE_AND_TIME' -- Date and time subroutine ================================================ _Description_: `DATE_AND_TIME(DATE, TIME, ZONE, VALUES)' gets the corresponding date and time information from the real-time system clock. DATE is `INTENT(OUT)' and has form ccyymmdd. TIME is `INTENT(OUT)' and has form hhmmss.sss. ZONE is `INTENT(OUT)' and has form (+-)hhmm, representing the difference with respect to Coordinated Universal Time (UTC). Unavailable time and date parameters return blanks. VALUES is `INTENT(OUT)' and provides the following: `VALUE(1)': The year `VALUE(2)': The month `VALUE(3)': The day of the month `VALUE(4)': Time difference with UTC in minutes `VALUE(5)': The hour of the day `VALUE(6)': The minutes of the hour `VALUE(7)': The seconds of the minute `VALUE(8)': The milliseconds of the second _Standard_: F95 and later _Class_: Subroutine _Syntax_: `CALL DATE_AND_TIME([DATE, TIME, ZONE, VALUES])' _Arguments_: DATE (Optional) The type shall be `CHARACTER(8)' or larger. TIME (Optional) The type shall be `CHARACTER(10)' or larger. ZONE (Optional) The type shall be `CHARACTER(5)' or larger. VALUES (Optional) The type shall be `INTEGER(8)'. _Return value_: None _Example_: program test_time_and_date character(8) :: date character(10) :: time character(5) :: zone integer,dimension(8) :: values ! using keyword arguments call date_and_time(date,time,zone,values) call date_and_time(DATE=date,ZONE=zone) call date_and_time(TIME=time) call date_and_time(VALUES=values) print '(a,2x,a,2x,a)', date, time, zone print '(8i5))', values end program test_time_and_date _See also_: *note CPU_TIME::, *note SYSTEM_CLOCK::  File: gfortran.info, Node: DBLE, Next: DCMPLX, Prev: DATE_AND_TIME, Up: Intrinsic Procedures 6.52 `DBLE' -- Double conversion function ========================================= _Description_: `DBLE(X)' Converts X to double precision real type. _Standard_: F77 and later _Class_: Elemental function _Syntax_: `RESULT = DBLE(X)' _Arguments_: X The type shall be `INTEGER(*)', `REAL(*)', or `COMPLEX(*)'. _Return value_: The return value is of type double precision real. _Example_: program test_dble real :: x = 2.18 integer :: i = 5 complex :: z = (2.3,1.14) print *, dble(x), dble(i), dble(z) end program test_dble _See also_: *note DFLOAT::, *note FLOAT::, *note REAL::  File: gfortran.info, Node: DCMPLX, Next: DFLOAT, Prev: DBLE, Up: Intrinsic Procedures 6.53 `DCMPLX' -- Double complex conversion function =================================================== _Description_: `DCMPLX(X [,Y])' returns a double complex number where X is converted to the real component. If Y is present it is converted to the imaginary component. If Y is not present then the imaginary component is set to 0.0. If X is complex then Y must not be present. _Standard_: GNU extension _Class_: Elemental function _Syntax_: `RESULT = DCMPLX(X [, Y])' _Arguments_: X The type may be `INTEGER(*)', `REAL(*)', or `COMPLEX(*)'. Y (Optional if X is not `COMPLEX(*)'.) May be `INTEGER(*)' or `REAL(*)'. _Return value_: The return value is of type `COMPLEX(8)' _Example_: program test_dcmplx integer :: i = 42 real :: x = 3.14 complex :: z z = cmplx(i, x) print *, dcmplx(i) print *, dcmplx(x) print *, dcmplx(z) print *, dcmplx(x,i) end program test_dcmplx  File: gfortran.info, Node: DFLOAT, Next: DIGITS, Prev: DCMPLX, Up: Intrinsic Procedures 6.54 `DFLOAT' -- Double conversion function =========================================== _Description_: `DFLOAT(X)' Converts X to double precision real type. _Standard_: GNU extension _Class_: Elemental function _Syntax_: `RESULT = DFLOAT(X)' _Arguments_: X The type shall be `INTEGER(*)'. _Return value_: The return value is of type double precision real. _Example_: program test_dfloat integer :: i = 5 print *, dfloat(i) end program test_dfloat _See also_: *note DBLE::, *note FLOAT::, *note REAL::  File: gfortran.info, Node: DIGITS, Next: DIM, Prev: DFLOAT, Up: Intrinsic Procedures 6.55 `DIGITS' -- Significant digits function ============================================ _Description_: `DIGITS(X)' returns the number of significant digits of the internal model representation of X. For example, on a system using a 32-bit floating point representation, a default real number would likely return 24. _Standard_: F95 and later _Class_: Inquiry function _Syntax_: `RESULT = DIGITS(X)' _Arguments_: X The type may be `INTEGER(*)' or `REAL(*)'. _Return value_: The return value is of type `INTEGER'. _Example_: program test_digits integer :: i = 12345 real :: x = 3.143 real(8) :: y = 2.33 print *, digits(i) print *, digits(x) print *, digits(y) end program test_digits  File: gfortran.info, Node: DIM, Next: DOT_PRODUCT, Prev: DIGITS, Up: Intrinsic Procedures 6.56 `DIM' -- Positive difference ================================= _Description_: `DIM(X,Y)' returns the difference `X-Y' if the result is positive; otherwise returns zero. _Standard_: F77 and later _Class_: Elemental function _Syntax_: `RESULT = DIM(X, Y)' _Arguments_: X The type shall be `INTEGER(*)' or `REAL(*)' Y The type shall be the same type and kind as X. _Return value_: The return value is of type `INTEGER(*)' or `REAL(*)'. _Example_: program test_dim integer :: i real(8) :: x i = dim(4, 15) x = dim(4.345_8, 2.111_8) print *, i print *, x end program test_dim _Specific names_: Name Argument Return type Standard `IDIM(X,Y)' `INTEGER(4) `INTEGER(4)' F77 and later X,Y' `DDIM(X,Y)' `REAL(8) `REAL(8)' F77 and later X,Y'  File: gfortran.info, Node: DOT_PRODUCT, Next: DPROD, Prev: DIM, Up: Intrinsic Procedures 6.57 `DOT_PRODUCT' -- Dot product function ========================================== _Description_: `DOT_PRODUCT(X,Y)' computes the dot product multiplication of two vectors X and Y. The two vectors may be either numeric or logical and must be arrays of rank one and of equal size. If the vectors are `INTEGER(*)' or `REAL(*)', the result is `SUM(X*Y)'. If the vectors are `COMPLEX(*)', the result is `SUM(CONJG(X)*Y)'. If the vectors are `LOGICAL', the result is `ANY(X.AND.Y)'. _Standard_: F95 and later _Class_: Transformational function _Syntax_: `RESULT = DOT_PRODUCT(X, Y)' _Arguments_: X The type shall be numeric or `LOGICAL', rank 1. Y The type shall be numeric or `LOGICAL', rank 1. _Return value_: If the arguments are numeric, the return value is a scaler of numeric type, `INTEGER(*)', `REAL(*)', or `COMPLEX(*)'. If the arguments are `LOGICAL', the return value is `.TRUE.' or `.FALSE.'. _Example_: program test_dot_prod integer, dimension(3) :: a, b a = (/ 1, 2, 3 /) b = (/ 4, 5, 6 /) print '(3i3)', a print * print '(3i3)', b print * print *, dot_product(a,b) end program test_dot_prod  File: gfortran.info, Node: DPROD, Next: DREAL, Prev: DOT_PRODUCT, Up: Intrinsic Procedures 6.58 `DPROD' -- Double product function ======================================= _Description_: `DPROD(X,Y)' returns the product `X*Y'. _Standard_: F77 and later _Class_: Elemental function _Syntax_: `RESULT = DPROD(X, Y)' _Arguments_: X The type shall be `REAL'. Y The type shall be `REAL'. _Return value_: The return value is of type `REAL(8)'. _Example_: program test_dprod real :: x = 5.2 real :: y = 2.3 real(8) :: d d = dprod(x,y) print *, d end program test_dprod  File: gfortran.info, Node: DREAL, Next: DTIME, Prev: DPROD, Up: Intrinsic Procedures 6.59 `DREAL' -- Double real part function ========================================= _Description_: `DREAL(Z)' returns the real part of complex variable Z. _Standard_: GNU extension _Class_: Elemental function _Syntax_: `RESULT = DREAL(Z)' _Arguments_: Z The type shall be `COMPLEX(8)'. _Return value_: The return value is of type `REAL(8)'. _Example_: program test_dreal complex(8) :: z = (1.3_8,7.2_8) print *, dreal(z) end program test_dreal _See also_: *note AIMAG::  File: gfortran.info, Node: DTIME, Next: EOSHIFT, Prev: DREAL, Up: Intrinsic Procedures 6.60 `DTIME' -- Execution time subroutine (or function) ======================================================= _Description_: `DTIME(TARRAY, RESULT)' initially returns the number of seconds of runtime since the start of the process's execution in RESULT. TARRAY returns the user and system components of this time in `TARRAY(1)' and `TARRAY(2)' respectively. RESULT is equal to `TARRAY(1) + TARRAY(2)'. Subsequent invocations of `DTIME' return values accumulated since the previous invocation. On some systems, the underlying timings are represented using types with sufficiently small limits that overflows (wrap around) are possible, such as 32-bit types. Therefore, the values returned by this intrinsic might be, or become, negative, or numerically less than previous values, during a single run of the compiled program. Please note, that this implementation is thread safe if used within OpenMP directives, i. e. its state will be consistent while called from multiple threads. However, if `DTIME' is called from multiple threads, the result is still the time since the last invocation. This may not give the intended results. If possible, use `CPU_TIME' instead. This intrinsic is provided in both subroutine and function forms; however, only one form can be used in any given program unit. TARRAY and RESULT are `INTENT(OUT)' and provide the following: `TARRAY(1)': User time in seconds. `TARRAY(2)': System time in seconds. `RESULT': Run time since start in seconds. _Standard_: GNU extension _Class_: Subroutine, function _Syntax_: `CALL DTIME(TARRAY, RESULT)'. `RESULT = DTIME(TARRAY)', (not recommended). _Arguments_: TARRAY The type shall be `REAL, DIMENSION(2)'. RESULT The type shall be `REAL'. _Return value_: Elapsed time in seconds since the last invocation or since the start of program execution if not called before. _Example_: program test_dtime integer(8) :: i, j real, dimension(2) :: tarray real :: result call dtime(tarray, result) print *, result print *, tarray(1) print *, tarray(2) do i=1,100000000 ! Just a delay j = i * i - i end do call dtime(tarray, result) print *, result print *, tarray(1) print *, tarray(2) end program test_dtime _See also_: *note CPU_TIME::  File: gfortran.info, Node: EOSHIFT, Next: EPSILON, Prev: DTIME, Up: Intrinsic Procedures 6.61 `EOSHIFT' -- End-off shift elements of an array ==================================================== _Description_: `EOSHIFT(ARRAY, SHIFT[,BOUNDARY, DIM])' performs an end-off shift on elements of ARRAY along the dimension of DIM. If DIM is omitted it is taken to be `1'. DIM is a scaler of type `INTEGER' in the range of 1 /leq DIM /leq n) where n is the rank of ARRAY. If the rank of ARRAY is one, then all elements of ARRAY are shifted by SHIFT places. If rank is greater than one, then all complete rank one sections of ARRAY along the given dimension are shifted. Elements shifted out one end of each rank one section are dropped. If BOUNDARY is present then the corresponding value of from BOUNDARY is copied back in the other end. If BOUNDARY is not present then the following are copied in depending on the type of ARRAY. _Array _Boundary Value_ Type_ Numeric 0 of the type and kind of ARRAY. Logical `.FALSE.'. Character(LEN)LEN blanks. _Standard_: F95 and later _Class_: Transformational function _Syntax_: `RESULT = EOSHIFT(ARRAY, SHIFT [, BOUNDARY, DIM])' _Arguments_: ARRAY May be any type, not scaler. SHIFT The type shall be `INTEGER'. BOUNDARY Same type as ARRAY. DIM The type shall be `INTEGER'. _Return value_: Returns an array of same type and rank as the ARRAY argument. _Example_: program test_eoshift integer, dimension(3,3) :: a a = reshape( (/ 1, 2, 3, 4, 5, 6, 7, 8, 9 /), (/ 3, 3 /)) print '(3i3)', a(1,:) print '(3i3)', a(2,:) print '(3i3)', a(3,:) a = EOSHIFT(a, SHIFT=(/1, 2, 1/), BOUNDARY=-5, DIM=2) print * print '(3i3)', a(1,:) print '(3i3)', a(2,:) print '(3i3)', a(3,:) end program test_eoshift  File: gfortran.info, Node: EPSILON, Next: ERF, Prev: EOSHIFT, Up: Intrinsic Procedures 6.62 `EPSILON' -- Epsilon function ================================== _Description_: `EPSILON(X)' returns a nearly negligible number relative to `1'. _Standard_: F95 and later _Class_: Inquiry function _Syntax_: `RESULT = EPSILON(X)' _Arguments_: X The type shall be `REAL(*)'. _Return value_: The return value is of same type as the argument. _Example_: program test_epsilon real :: x = 3.143 real(8) :: y = 2.33 print *, EPSILON(x) print *, EPSILON(y) end program test_epsilon  File: gfortran.info, Node: ERF, Next: ERFC, Prev: EPSILON, Up: Intrinsic Procedures 6.63 `ERF' -- Error function ============================ _Description_: `ERF(X)' computes the error function of X. _Standard_: GNU Extension _Class_: Elemental function _Syntax_: `RESULT = ERF(X)' _Arguments_: X The type shall be `REAL(*)', and it shall be scalar. _Return value_: The return value is a scalar of type `REAL(*)' and it is positive ( - 1 \leq erf (x) \leq 1 . _Example_: program test_erf real(8) :: x = 0.17_8 x = erf(x) end program test_erf _Specific names_: Name Argument Return type Standard `DERF(X)' `REAL(8) X' `REAL(8)' GNU extension  File: gfortran.info, Node: ERFC, Next: ETIME, Prev: ERF, Up: Intrinsic Procedures 6.64 `ERFC' -- Error function ============================= _Description_: `ERFC(X)' computes the complementary error function of X. _Standard_: GNU extension _Class_: Elemental function _Syntax_: `RESULT = ERFC(X)' _Arguments_: X The type shall be `REAL(*)', and it shall be scalar. _Return value_: The return value is a scalar of type `REAL(*)' and it is positive ( 0 \leq erfc (x) \leq 2 . _Example_: program test_erfc real(8) :: x = 0.17_8 x = erfc(x) end program test_erfc _Specific names_: Name Argument Return type Standard `DERFC(X)' `REAL(8) X' `REAL(8)' GNU extension  File: gfortran.info, Node: ETIME, Next: EXIT, Prev: ERFC, Up: Intrinsic Procedures 6.65 `ETIME' -- Execution time subroutine (or function) ======================================================= _Description_: `ETIME(TARRAY, RESULT)' returns the number of seconds of runtime since the start of the process's execution in RESULT. TARRAY returns the user and system components of this time in `TARRAY(1)' and `TARRAY(2)' respectively. RESULT is equal to `TARRAY(1) + TARRAY(2)'. On some systems, the underlying timings are represented using types with sufficiently small limits that overflows (wrap around) are possible, such as 32-bit types. Therefore, the values returned by this intrinsic might be, or become, negative, or numerically less than previous values, during a single run of the compiled program. This intrinsic is provided in both subroutine and function forms; however, only one form can be used in any given program unit. TARRAY and RESULT are `INTENT(OUT)' and provide the following: `TARRAY(1)': User time in seconds. `TARRAY(2)': System time in seconds. `RESULT': Run time since start in seconds. _Standard_: GNU extension _Class_: Subroutine, function _Syntax_: `CALL ETIME(TARRAY, RESULT)'. `RESULT = ETIME(TARRAY)', (not recommended). _Arguments_: TARRAY The type shall be `REAL, DIMENSION(2)'. RESULT The type shall be `REAL'. _Return value_: Elapsed time in seconds since the start of program execution. _Example_: program test_etime integer(8) :: i, j real, dimension(2) :: tarray real :: result call ETIME(tarray, result) print *, result print *, tarray(1) print *, tarray(2) do i=1,100000000 ! Just a delay j = i * i - i end do call ETIME(tarray, result) print *, result print *, tarray(1) print *, tarray(2) end program test_etime _See also_: *note CPU_TIME::  File: gfortran.info, Node: EXIT, Next: EXP, Prev: ETIME, Up: Intrinsic Procedures 6.66 `EXIT' -- Exit the program with status. ============================================ _Description_: `EXIT' causes immediate termination of the program with status. If status is omitted it returns the canonical _success_ for the system. All Fortran I/O units are closed. _Standard_: GNU extension _Class_: Subroutine _Syntax_: `CALL EXIT([STATUS])' _Arguments_: STATUS Shall be an `INTEGER' of the default kind. _Return value_: `STATUS' is passed to the parent process on exit. _Example_: program test_exit integer :: STATUS = 0 print *, 'This program is going to exit.' call EXIT(STATUS) end program test_exit _See also_: *note ABORT::, *note KILL::  File: gfortran.info, Node: EXP, Next: EXPONENT, Prev: EXIT, Up: Intrinsic Procedures 6.67 `EXP' -- Exponential function ================================== _Description_: `EXP(X)' computes the base e exponential of X. _Standard_: F77 and later, has overloads that are GNU extensions _Class_: Elemental function _Syntax_: `RESULT = EXP(X)' _Arguments_: X The type shall be `REAL(*)' or `COMPLEX(*)'. _Return value_: The return value has same type and kind as X. _Example_: program test_exp real :: x = 1.0 x = exp(x) end program test_exp _Specific names_: Name Argument Return type Standard `DEXP(X)' `REAL(8) X' `REAL(8)' F77 and later `CEXP(X)' `COMPLEX(4) `COMPLEX(4)' F77 and later X' `ZEXP(X)' `COMPLEX(8) `COMPLEX(8)' GNU extension X' `CDEXP(X)' `COMPLEX(8) `COMPLEX(8)' GNU extension X'  File: gfortran.info, Node: EXPONENT, Next: FDATE, Prev: EXP, Up: Intrinsic Procedures 6.68 `EXPONENT' -- Exponent function ==================================== _Description_: `EXPONENT(X)' returns the value of the exponent part of X. If X is zero the value returned is zero. _Standard_: F95 and later _Class_: Elemental function _Syntax_: `RESULT = EXPONENT(X)' _Arguments_: X The type shall be `REAL(*)'. _Return value_: The return value is of type default `INTEGER'. _Example_: program test_exponent real :: x = 1.0 integer :: i i = exponent(x) print *, i print *, exponent(0.0) end program test_exponent  File: gfortran.info, Node: FDATE, Next: FGET, Prev: EXPONENT, Up: Intrinsic Procedures 6.69 `FDATE' -- Get the current time as a string ================================================ _Description_: `FDATE(DATE)' returns the current date (using the same format as `CTIME') in DATE. It is equivalent to `CALL CTIME(DATE, TIME())'. This intrinsic is provided in both subroutine and function forms; however, only one form can be used in any given program unit. DATE is an `INTENT(OUT)' `CHARACTER' variable. _Standard_: GNU extension _Class_: Subroutine, function _Syntax_: `CALL FDATE(DATE)'. `DATE = FDATE()', (not recommended). _Arguments_: DATE The type shall be of type `CHARACTER'. _Return value_: The current date as a string. _Example_: program test_fdate integer(8) :: i, j character(len=30) :: date call fdate(date) print *, 'Program started on ', date do i = 1, 100000000 ! Just a delay j = i * i - i end do call fdate(date) print *, 'Program ended on ', date end program test_fdate  File: gfortran.info, Node: FLOAT, Next: FLOOR, Prev: FGETC, Up: Intrinsic Procedures 6.70 `FLOAT' -- Convert integer to default real =============================================== _Description_: `FLOAT(I)' converts the integer I to a default real value. _Standard_: F77 and later _Class_: Elemental function _Syntax_: `RESULT = FLOAT(I)' _Arguments_: I The type shall be `INTEGER(*)'. _Return value_: The return value is of type default `REAL'. _Example_: program test_float integer :: i = 1 if (float(i) /= 1.) call abort end program test_float _See also_: *note DBLE::, *note DFLOAT::, *note REAL::  File: gfortran.info, Node: FGET, Next: FGETC, Prev: FDATE, Up: Intrinsic Procedures 6.71 `FGET' -- Read a single character in stream mode from stdin ================================================================ _Description_: Read a single character in stream mode from stdin by bypassing normal formatted output. Stream I/O should not be mixed with normal record-oriented (formatted or unformatted) I/O on the same unit; the results are unpredictable. This intrinsic is provided in both subroutine and function forms; however, only one form can be used in any given program unit. Note that the `FGET' intrinsic is provided for backwards compatibility with `g77'. GNU Fortran provides the Fortran 2003 Stream facility. Programmers should consider the use of new stream IO feature in new code for future portability. See also *note Fortran 2003 status::. _Standard_: GNU extension _Class_: Subroutine, function _Syntax_: `CALL FGET(C [, STATUS])' _Arguments_: C The type shall be `CHARACTER'. STATUS (Optional) status flag of type `INTEGER'. Returns 0 on success, -1 on end-of-file, and a system specific positive error code otherwise. _Example_: PROGRAM test_fget INTEGER, PARAMETER :: strlen = 100 INTEGER :: status, i = 1 CHARACTER(len=strlen) :: str = "" WRITE (*,*) 'Enter text:' DO CALL fget(str(i:i), status) if (status /= 0 .OR. i > strlen) exit i = i + 1 END DO WRITE (*,*) TRIM(str) END PROGRAM _See also_: *note FGETC::, *note FPUT::, *note FPUTC::  File: gfortran.info, Node: FGETC, Next: FLOAT, Prev: FGET, Up: Intrinsic Procedures 6.72 `FGETC' -- Read a single character in stream mode ====================================================== _Description_: Read a single character in stream mode by bypassing normal formatted output. Stream I/O should not be mixed with normal record-oriented (formatted or unformatted) I/O on the same unit; the results are unpredictable. This intrinsic is provided in both subroutine and function forms; however, only one form can be used in any given program unit. Note that the `FGET' intrinsic is provided for backwards compatibility with `g77'. GNU Fortran provides the Fortran 2003 Stream facility. Programmers should consider the use of new stream IO feature in new code for future portability. See also *note Fortran 2003 status::. _Standard_: GNU extension _Class_: Subroutine, function _Syntax_: `CALL FGETC(UNIT, C [, STATUS])' _Arguments_: UNIT The type shall be `INTEGER'. C The type shall be `CHARACTER'. STATUS (Optional) status flag of type `INTEGER'. Returns 0 on success, -1 on end-of-file and a system specific positive error code otherwise. _Example_: PROGRAM test_fgetc INTEGER :: fd = 42, status CHARACTER :: c OPEN(UNIT=fd, FILE="/etc/passwd", ACTION="READ", STATUS = "OLD") DO CALL fgetc(fd, c, status) IF (status /= 0) EXIT call fput(c) END DO CLOSE(UNIT=fd) END PROGRAM _See also_: *note FGET::, *note FPUT::, *note FPUTC::  File: gfortran.info, Node: FLOOR, Next: FLUSH, Prev: FLOAT, Up: Intrinsic Procedures 6.73 `FLOOR' -- Integer floor function ====================================== _Description_: `FLOOR(X)' returns the greatest integer less than or equal to X. _Standard_: F95 and later _Class_: Elemental function _Syntax_: `RESULT = FLOOR(X [, KIND])' _Arguments_: X The type shall be `REAL(*)'. KIND (Optional) An `INTEGER(*)' initialization expression indicating the kind parameter of the result. _Return value_: The return value is of type `INTEGER(KIND)' _Example_: program test_floor real :: x = 63.29 real :: y = -63.59 print *, floor(x) ! returns 63 print *, floor(y) ! returns -64 end program test_floor _See also_: *note CEILING::, *note NINT::  File: gfortran.info, Node: FLUSH, Next: FNUM, Prev: FLOOR, Up: Intrinsic Procedures 6.74 `FLUSH' -- Flush I/O unit(s) ================================= _Description_: Flushes Fortran unit(s) currently open for output. Without the optional argument, all units are flushed, otherwise just the unit specified. _Standard_: GNU extension _Class_: Subroutine _Syntax_: `CALL FLUSH(UNIT)' _Arguments_: UNIT (Optional) The type shall be `INTEGER'. _Note_: Beginning with the Fortran 2003 standard, there is a `FLUSH' statement that should be preferred over the `FLUSH' intrinsic.  File: gfortran.info, Node: FNUM, Next: FPUT, Prev: FLUSH, Up: Intrinsic Procedures 6.75 `FNUM' -- File number function =================================== _Description_: `FNUM(UNIT)' returns the POSIX file descriptor number corresponding to the open Fortran I/O unit `UNIT'. _Standard_: GNU extension _Class_: Function _Syntax_: `RESULT = FNUM(UNIT)' _Arguments_: UNIT The type shall be `INTEGER'. _Return value_: The return value is of type `INTEGER' _Example_: program test_fnum integer :: i open (unit=10, status = "scratch") i = fnum(10) print *, i close (10) end program test_fnum  File: gfortran.info, Node: FPUT, Next: FPUTC, Prev: FNUM, Up: Intrinsic Procedures 6.76 `FPUT' -- Write a single character in stream mode to stdout ================================================================ _Description_: Write a single character in stream mode to stdout by bypassing normal formatted output. Stream I/O should not be mixed with normal record-oriented (formatted or unformatted) I/O on the same unit; the results are unpredictable. This intrinsic is provided in both subroutine and function forms; however, only one form can be used in any given program unit. Note that the `FGET' intrinsic is provided for backwards compatibility with `g77'. GNU Fortran provides the Fortran 2003 Stream facility. Programmers should consider the use of new stream IO feature in new code for future portability. See also *note Fortran 2003 status::. _Standard_: GNU extension _Class_: Subroutine, function _Syntax_: `CALL FPUT(C [, STATUS])' _Arguments_: C The type shall be `CHARACTER'. STATUS (Optional) status flag of type `INTEGER'. Returns 0 on success, -1 on end-of-file and a system specific positive error code otherwise. _Example_: PROGRAM test_fput CHARACTER(len=10) :: str = "gfortran" INTEGER :: i DO i = 1, len_trim(str) CALL fput(str(i:i)) END DO END PROGRAM _See also_: *note FPUTC::, *note FGET::, *note FGETC::  File: gfortran.info, Node: FPUTC, Next: FRACTION, Prev: FPUT, Up: Intrinsic Procedures 6.77 `FPUTC' -- Write a single character in stream mode ======================================================= _Description_: Write a single character in stream mode by bypassing normal formatted output. Stream I/O should not be mixed with normal record-oriented (formatted or unformatted) I/O on the same unit; the results are unpredictable. This intrinsic is provided in both subroutine and function forms; however, only one form can be used in any given program unit. Note that the `FGET' intrinsic is provided for backwards compatibility with `g77'. GNU Fortran provides the Fortran 2003 Stream facility. Programmers should consider the use of new stream IO feature in new code for future portability. See also *note Fortran 2003 status::. _Standard_: GNU extension _Class_: Subroutine, function _Syntax_: `CALL FPUTC(UNIT, C [, STATUS])' _Arguments_: UNIT The type shall be `INTEGER'. C The type shall be `CHARACTER'. STATUS (Optional) status flag of type `INTEGER'. Returns 0 on success, -1 on end-of-file and a system specific positive error code otherwise. _Example_: PROGRAM test_fputc CHARACTER(len=10) :: str = "gfortran" INTEGER :: fd = 42, i OPEN(UNIT = fd, FILE = "out", ACTION = "WRITE", STATUS="NEW") DO i = 1, len_trim(str) CALL fputc(fd, str(i:i)) END DO CLOSE(fd) END PROGRAM _See also_: *note FPUT::, *note FGET::, *note FGETC::  File: gfortran.info, Node: FRACTION, Next: FREE, Prev: FPUTC, Up: Intrinsic Procedures 6.78 `FRACTION' -- Fractional part of the model representation ============================================================== _Description_: `FRACTION(X)' returns the fractional part of the model representation of `X'. _Standard_: F95 and later _Class_: Elemental function _Syntax_: `Y = FRACTION(X)' _Arguments_: X The type of the argument shall be a `REAL'. _Return value_: The return value is of the same type and kind as the argument. The fractional part of the model representation of `X' is returned; it is `X * RADIX(X)**(-EXPONENT(X))'. _Example_: program test_fraction real :: x x = 178.1387e-4 print *, fraction(x), x * radix(x)**(-exponent(x)) end program test_fraction  File: gfortran.info, Node: FREE, Next: FSEEK, Prev: FRACTION, Up: Intrinsic Procedures 6.79 `FREE' -- Frees memory =========================== _Description_: Frees memory previously allocated by `MALLOC()'. The `FREE' intrinsic is an extension intended to be used with Cray pointers, and is provided in GNU Fortran to allow user to compile legacy code. For new code using Fortran 95 pointers, the memory de-allocation intrinsic is `DEALLOCATE'. _Standard_: GNU extension _Class_: Subroutine _Syntax_: `CALL FREE(PTR)' _Arguments_: PTR The type shall be `INTEGER'. It represents the location of the memory that should be de-allocated. _Return value_: None _Example_: See `MALLOC' for an example. _See also_: *note MALLOC::  File: gfortran.info, Node: FSEEK, Next: FSTAT, Prev: FREE, Up: Intrinsic Procedures 6.80 `FSEEK' -- Low level file positioning subroutine ===================================================== _Description_: Moves UNIT to the specified OFFSET. If WHENCE is set to 0, the OFFSET is taken as an absolute value `SEEK_SET', if set to 1, OFFSET is taken to be relative to the current position `SEEK_CUR', and if set to 2 relative to the end of the file `SEEK_END'. On error, STATUS is set to a nonzero value. If STATUS the seek fails silently. This intrinsic routine is not fully backwards compatible with `g77'. In `g77', the `FSEEK' takes a statement label instead of a STATUS variable. If FSEEK is used in old code, change CALL FSEEK(UNIT, OFFSET, WHENCE, *label) to INTEGER :: status CALL FSEEK(UNIT, OFFSET, WHENCE, status) IF (status /= 0) GOTO label Please note that GNU Fortran provides the Fortran 2003 Stream facility. Programmers should consider the use of new stream IO feature in new code for future portability. See also *note Fortran 2003 status::. _Standard_: GNU extension _Class_: Subroutine _Syntax_: `CALL FSEEK(UNIT, OFFSET, WHENCE[, STATUS])' _Arguments_: UNIT Shall be a scalar of type `INTEGER'. OFFSET Shall be a scalar of type `INTEGER'. WHENCE Shall be a scalar of type `INTEGER'. Its value shall be either 0, 1 or 2. STATUS (Optional) shall be a scalar of type `INTEGER(4)'. _Example_: PROGRAM test_fseek INTEGER, PARAMETER :: SEEK_SET = 0, SEEK_CUR = 1, SEEK_END = 2 INTEGER :: fd, offset, ierr ierr = 0 offset = 5 fd = 10 OPEN(UNIT=fd, FILE="fseek.test") CALL FSEEK(fd, offset, SEEK_SET, ierr) ! move to OFFSET print *, FTELL(fd), ierr CALL FSEEK(fd, 0, SEEK_END, ierr) ! move to end print *, FTELL(fd), ierr CALL FSEEK(fd, 0, SEEK_SET, ierr) ! move to beginning print *, FTELL(fd), ierr CLOSE(UNIT=fd) END PROGRAM _See also_: *note FTELL::  File: gfortran.info, Node: FSTAT, Next: FTELL, Prev: FSEEK, Up: Intrinsic Procedures 6.81 `FSTAT' -- Get file status =============================== _Description_: `FSTAT' is identical to *note STAT::, except that information about an already opened file is obtained. The elements in `BUFF' are the same as described by *note STAT::. This intrinsic is provided in both subroutine and function forms; however, only one form can be used in any given program unit. _Standard_: GNU extension _Class_: Subroutine, function _Syntax_: `CALL FSTAT(UNIT, BUFF [, STATUS])' _Arguments_: UNIT An open I/O unit number of type `INTEGER'. BUFF The type shall be `INTEGER(4), DIMENSION(13)'. STATUS (Optional) status flag of type `INTEGER(4)'. Returns 0 on success and a system specific error code otherwise. _Example_: See *note STAT:: for an example. _See also_: To stat a link: *note LSTAT::, to stat a file: *note STAT::  File: gfortran.info, Node: FTELL, Next: GAMMA, Prev: FSTAT, Up: Intrinsic Procedures 6.82 `FTELL' -- Current stream position ======================================= _Description_: Retrieves the current position within an open file. This intrinsic is provided in both subroutine and function forms; however, only one form can be used in any given program unit. _Standard_: GNU extension _Class_: Subroutine, function _Syntax_: `CALL FTELL(UNIT, OFFSET)' `OFFSET = FTELL(UNIT)' _Arguments_: OFFSET Shall of type `INTEGER'. UNIT Shall of type `INTEGER'. _Return value_: In either syntax, OFFSET is set to the current offset of unit number UNIT, or to -1 if the unit is not currently open. _Example_: PROGRAM test_ftell INTEGER :: i OPEN(10, FILE="temp.dat") CALL ftell(10,i) WRITE(*,*) i END PROGRAM _See also_: *note FSEEK::  File: gfortran.info, Node: GAMMA, Next: GERROR, Prev: FTELL, Up: Intrinsic Procedures 6.83 `GAMMA' -- Gamma function ============================== _Description_: `GAMMA(X)' computes Gamma (\Gamma) of X. For positive, integer values of X the Gamma function simplifies to the factorial function \Gamma(x)=(x-1)!. _Standard_: GNU Extension _Class_: Elemental function _Syntax_: `X = GAMMA(X)' _Arguments_: X Shall be of type `REAL' and neither zero nor a negative integer. _Return value_: The return value is of type `REAL' of the same kind as X. _Example_: program test_gamma real :: x = 1.0 x = gamma(x) ! returns 1.0 end program test_gamma _Specific names_: Name Argument Return type Standard `GAMMA(X)' `REAL(4) X' `REAL(4)' GNU Extension `DGAMMA(X)' `REAL(8) X' `REAL(8)' GNU Extension _See also_: Logarithm of the Gamma function: *note LGAMMA::  File: gfortran.info, Node: GERROR, Next: GETARG, Prev: GAMMA, Up: Intrinsic Procedures 6.84 `GERROR' -- Get last system error message ============================================== _Description_: Returns the system error message corresponding to the last system error. This resembles the functionality of `strerror(3)' in C. _Standard_: GNU extension _Class_: Subroutine _Syntax_: `CALL GERROR(RESULT)' _Arguments_: RESULT Shall of type `CHARACTER(*)'. _Example_: PROGRAM test_gerror CHARACTER(len=100) :: msg CALL gerror(msg) WRITE(*,*) msg END PROGRAM _See also_: *note IERRNO::, *note PERROR::  File: gfortran.info, Node: GETARG, Next: GET_COMMAND, Prev: GERROR, Up: Intrinsic Procedures 6.85 `GETARG' -- Get command line arguments =========================================== _Description_: Retrieve the Nth argument that was passed on the command line when the containing program was invoked. This intrinsic routine is provided for backwards compatibility with GNU Fortran 77. In new code, programmers should consider the use of the *note GET_COMMAND_ARGUMENT:: intrinsic defined by the Fortran 2003 standard. _Standard_: GNU extension _Class_: Subroutine _Syntax_: `CALL GETARG(POS, VALUE)' _Arguments_: POS Shall be of type `INTEGER' and not wider than the default integer kind; POS \geq 0 VALUE Shall be of type `CHARACTER(*)'. _Return value_: After `GETARG' returns, the VALUE argument holds the POSth command line argument. If VALUE can not hold the argument, it is truncated to fit the length of VALUE. If there are less than POS arguments specified at the command line, VALUE will be filled with blanks. If POS = 0, VALUE is set to the name of the program (on systems that support this feature). _Example_: PROGRAM test_getarg INTEGER :: i CHARACTER(len=32) :: arg DO i = 1, iargc() CALL getarg(i, arg) WRITE (*,*) arg END DO END PROGRAM _See also_: GNU Fortran 77 compatibility function: *note IARGC:: F2003 functions and subroutines: *note GET_COMMAND::, *note GET_COMMAND_ARGUMENT::, *note COMMAND_ARGUMENT_COUNT::  File: gfortran.info, Node: GET_COMMAND, Next: GET_COMMAND_ARGUMENT, Prev: GETARG, Up: Intrinsic Procedures 6.86 `GET_COMMAND' -- Get the entire command line ================================================= _Description_: Retrieve the entire command line that was used to invoke the program. _Standard_: F2003 _Class_: Subroutine _Syntax_: `CALL GET_COMMAND(CMD)' _Arguments_: CMD Shall be of type `CHARACTER(*)'. _Return value_: Stores the entire command line that was used to invoke the program in ARG. If ARG is not large enough, the command will be truncated. _Example_: PROGRAM test_get_command CHARACTER(len=255) :: cmd CALL get_command(cmd) WRITE (*,*) TRIM(cmd) END PROGRAM _See also_: *note GET_COMMAND_ARGUMENT::, *note COMMAND_ARGUMENT_COUNT::  File: gfortran.info, Node: GET_COMMAND_ARGUMENT, Next: GETCWD, Prev: GET_COMMAND, Up: Intrinsic Procedures 6.87 `GET_COMMAND_ARGUMENT' -- Get command line arguments ========================================================= _Description_: Retrieve the Nth argument that was passed on the command line when the containing program was invoked. _Standard_: F2003 _Class_: Subroutine _Syntax_: `CALL GET_COMMAND_ARGUMENT(N, ARG)' _Arguments_: N Shall be of type `INTEGER(4)', N \geq 0 ARG Shall be of type `CHARACTER(*)'. _Return value_: After `GET_COMMAND_ARGUMENT' returns, the ARG argument holds the Nth command line argument. If ARG can not hold the argument, it is truncated to fit the length of ARG. If there are less than N arguments specified at the command line, ARG will be filled with blanks. If N = 0, ARG is set to the name of the program (on systems that support this feature). _Example_: PROGRAM test_get_command_argument INTEGER :: i CHARACTER(len=32) :: arg i = 0 DO CALL get_command_argument(i, arg) IF (LEN_TRIM(arg) == 0) EXIT WRITE (*,*) TRIM(arg) i = i+1 END DO END PROGRAM _See also_: *note GET_COMMAND::, *note COMMAND_ARGUMENT_COUNT::  File: gfortran.info, Node: GETCWD, Next: GETENV, Prev: GET_COMMAND_ARGUMENT, Up: Intrinsic Procedures 6.88 `GETCWD' -- Get current working directory ============================================== _Description_: Get current working directory. This intrinsic is provided in both subroutine and function forms; however, only one form can be used in any given program unit. _Standard_: GNU extension _Class_: Subroutine, function _Syntax_: `CALL GETCWD(CWD [, STATUS])' _Arguments_: CWD The type shall be `CHARACTER(*)'. STATUS (Optional) status flag. Returns 0 on success, a system specific and nonzero error code otherwise. _Example_: PROGRAM test_getcwd CHARACTER(len=255) :: cwd CALL getcwd(cwd) WRITE(*,*) TRIM(cwd) END PROGRAM _See also_: *note CHDIR::  File: gfortran.info, Node: GETENV, Next: GET_ENVIRONMENT_VARIABLE, Prev: GETCWD, Up: Intrinsic Procedures 6.89 `GETENV' -- Get an environmental variable ============================================== _Description_: Get the VALUE of the environmental variable ENVVAR. This intrinsic routine is provided for backwards compatibility with GNU Fortran 77. In new code, programmers should consider the use of the *note GET_ENVIRONMENT_VARIABLE:: intrinsic defined by the Fortran 2003 standard. _Standard_: GNU extension _Class_: Subroutine _Syntax_: `CALL GETENV(ENVVAR, VALUE)' _Arguments_: ENVVAR Shall be of type `CHARACTER(*)'. VALUE Shall be of type `CHARACTER(*)'. _Return value_: Stores the value of ENVVAR in VALUE. If VALUE is not large enough to hold the data, it is truncated. If ENVVAR is not set, VALUE will be filled with blanks. _Example_: PROGRAM test_getenv CHARACTER(len=255) :: homedir CALL getenv("HOME", homedir) WRITE (*,*) TRIM(homedir) END PROGRAM _See also_: *note GET_ENVIRONMENT_VARIABLE::  File: gfortran.info, Node: GET_ENVIRONMENT_VARIABLE, Next: GETGID, Prev: GETENV, Up: Intrinsic Procedures 6.90 `GET_ENVIRONMENT_VARIABLE' -- Get an environmental variable ================================================================ _Description_: Get the VALUE of the environmental variable ENVVAR. _Standard_: F2003 _Class_: Subroutine _Syntax_: `CALL GET_ENVIRONMENT_VARIABLE(ENVVAR, VALUE)' _Arguments_: ENVVAR Shall be of type `CHARACTER(*)'. VALUE Shall be of type `CHARACTER(*)'. _Return value_: Stores the value of ENVVAR in VALUE. If VALUE is not large enough to hold the data, it is truncated. If ENVVAR is not set, VALUE will be filled with blanks. _Example_: PROGRAM test_getenv CHARACTER(len=255) :: homedir CALL get_environment_variable("HOME", homedir) WRITE (*,*) TRIM(homedir) END PROGRAM  File: gfortran.info, Node: GETGID, Next: GETLOG, Prev: GET_ENVIRONMENT_VARIABLE, Up: Intrinsic Procedures 6.91 `GETGID' -- Group ID function ================================== _Description_: Returns the numerical group ID of the current process. _Standard_: GNU extension _Class_: Function _Syntax_: `RESULT = GETGID()' _Return value_: The return value of `GETGID' is an `INTEGER' of the default kind. _Example_: See `GETPID' for an example. _See also_: *note GETPID::, *note GETUID::  File: gfortran.info, Node: GETLOG, Next: GETPID, Prev: GETGID, Up: Intrinsic Procedures 6.92 `GETLOG' -- Get login name =============================== _Description_: Gets the username under which the program is running. _Standard_: GNU extension _Class_: Subroutine _Syntax_: `CALL GETLOG(LOGIN)' _Arguments_: LOGIN Shall be of type `CHARACTER(*)'. _Return value_: Stores the current user name in LOGIN. (On systems where POSIX functions `geteuid' and `getpwuid' are not available, and the `getlogin' function is not implemented either, this will return a blank string.) _Example_: PROGRAM TEST_GETLOG CHARACTER(32) :: login CALL GETLOG(login) WRITE(*,*) login END PROGRAM _See also_: *note GETUID::  File: gfortran.info, Node: GETPID, Next: GETUID, Prev: GETLOG, Up: Intrinsic Procedures 6.93 `GETPID' -- Process ID function ==================================== _Description_: Returns the numerical process identifier of the current process. _Standard_: GNU extension _Class_: Function _Syntax_: `RESULT = GETPID()' _Return value_: The return value of `GETPID' is an `INTEGER' of the default kind. _Example_: program info print *, "The current process ID is ", getpid() print *, "Your numerical user ID is ", getuid() print *, "Your numerical group ID is ", getgid() end program info _See also_: *note GETGID::, *note GETUID::  File: gfortran.info, Node: GETUID, Next: GMTIME, Prev: GETPID, Up: Intrinsic Procedures 6.94 `GETUID' -- User ID function ================================= _Description_: Returns the numerical user ID of the current process. _Standard_: GNU extension _Class_: Function _Syntax_: `RESULT = GETUID()' _Return value_: The return value of `GETUID' is an `INTEGER' of the default kind. _Example_: See `GETPID' for an example. _See also_: *note GETPID::, *note GETLOG::  File: gfortran.info, Node: GMTIME, Next: HOSTNM, Prev: GETUID, Up: Intrinsic Procedures 6.95 `GMTIME' -- Convert time to GMT info ========================================= _Description_: Given a system time value STIME (as provided by the `TIME8()' intrinsic), fills TARRAY with values extracted from it appropriate to the UTC time zone (Universal Coordinated Time, also known in some countries as GMT, Greenwich Mean Time), using `gmtime(3)'. _Standard_: GNU extension _Class_: Subroutine _Syntax_: `CALL GMTIME(STIME, TARRAY)' _Arguments_: STIME An `INTEGER(*)' scalar expression corresponding to a system time, with `INTENT(IN)'. TARRAY A default `INTEGER' array with 9 elements, with `INTENT(OUT)'. _Return value_: The elements of TARRAY are assigned as follows: 1. Seconds after the minute, range 0-59 or 0-61 to allow for leap seconds 2. Minutes after the hour, range 0-59 3. Hours past midnight, range 0-23 4. Day of month, range 0-31 5. Number of months since January, range 0-12 6. Years since 1900 7. Number of days since Sunday, range 0-6 8. Days since January 1 9. Daylight savings indicator: positive if daylight savings is in effect, zero if not, and negative if the information is not available. _See also_: *note CTIME::, *note LTIME::, *note TIME::, *note TIME8::  File: gfortran.info, Node: HOSTNM, Next: HUGE, Prev: GMTIME, Up: Intrinsic Procedures 6.96 `HOSTNM' -- Get system host name ===================================== _Description_: Retrieves the host name of the system on which the program is running. This intrinsic is provided in both subroutine and function forms; however, only one form can be used in any given program unit. _Standard_: GNU extension _Class_: Subroutine, function _Syntax_: `CALL HOSTNM(NAME[, STATUS])' `STATUS = HOSTNM(NAME)' _Arguments_: NAME Shall of type `CHARACTER(*)'. STATUS (Optional) status flag of type `INTEGER'. Returns 0 on success, or a system specific error code otherwise. _Return value_: In either syntax, NAME is set to the current hostname if it can be obtained, or to a blank string otherwise.  File: gfortran.info, Node: HUGE, Next: IACHAR, Prev: HOSTNM, Up: Intrinsic Procedures 6.97 `HUGE' -- Largest number of a kind ======================================= _Description_: `HUGE(X)' returns the largest number that is not an infinity in the model of the type of `X'. _Standard_: F95 and later _Class_: Inquiry function _Syntax_: `RESULT = HUGE(X)' _Arguments_: X Shall be of type `REAL' or `INTEGER'. _Return value_: The return value is of the same type and kind as X _Example_: program test_huge_tiny print *, huge(0), huge(0.0), huge(0.0d0) print *, tiny(0.0), tiny(0.0d0) end program test_huge_tiny  File: gfortran.info, Node: IACHAR, Next: IAND, Prev: HUGE, Up: Intrinsic Procedures 6.98 `IACHAR' -- Code in ASCII collating sequence ================================================= _Description_: `IACHAR(C)' returns the code for the ASCII character in the first character position of `C'. _Standard_: F95 and later _Class_: Elemental function _Syntax_: `RESULT = IACHAR(C [, KIND])' _Arguments_: C Shall be a scalar `CHARACTER', with `INTENT(IN)' KIND (Optional) An `INTEGER' initialization expression indicating the kind parameter of the result. _Return value_: The return value is of type `INTEGER' and of kind KIND. If KIND is absent, the return value is of default integer kind. _Example_: program test_iachar integer i i = iachar(' ') end program test_iachar _Note_: See *note ICHAR:: for a discussion of converting between numerical values and formatted string representations. _See also_: *note ACHAR::, *note CHAR::, *note ICHAR::  File: gfortran.info, Node: IAND, Next: IARGC, Prev: IACHAR, Up: Intrinsic Procedures 6.99 `IAND' -- Bitwise logical and ================================== _Description_: Bitwise logical `AND'. _Standard_: F95 and later _Class_: Elemental function _Syntax_: `RESULT = IAND(I, J)' _Arguments_: I The type shall be `INTEGER(*)'. J The type shall be `INTEGER(*)', of the same kind as I. (As a GNU extension, different kinds are also permitted.) _Return value_: The return type is `INTEGER(*)', of the same kind as the arguments. (If the argument kinds differ, it is of the same kind as the larger argument.) _Example_: PROGRAM test_iand INTEGER :: a, b DATA a / Z'F' /, b / Z'3' / WRITE (*,*) IAND(a, b) END PROGRAM _See also_: *note IOR::, *note IEOR::, *note IBITS::, *note IBSET::, *note IBCLR::, *note NOT::  File: gfortran.info, Node: IARGC, Next: IBCLR, Prev: IAND, Up: Intrinsic Procedures 6.100 `IARGC' -- Get the number of command line arguments ========================================================= _Description_: `IARGC()' returns the number of arguments passed on the command line when the containing program was invoked. This intrinsic routine is provided for backwards compatibility with GNU Fortran 77. In new code, programmers should consider the use of the *note COMMAND_ARGUMENT_COUNT:: intrinsic defined by the Fortran 2003 standard. _Standard_: GNU extension _Class_: Function _Syntax_: `RESULT = IARGC()' _Arguments_: None. _Return value_: The number of command line arguments, type `INTEGER(4)'. _Example_: See *note GETARG:: _See also_: GNU Fortran 77 compatibility subroutine: *note GETARG:: F2003 functions and subroutines: *note GET_COMMAND::, *note GET_COMMAND_ARGUMENT::, *note COMMAND_ARGUMENT_COUNT::  File: gfortran.info, Node: IBCLR, Next: IBITS, Prev: IARGC, Up: Intrinsic Procedures 6.101 `IBCLR' -- Clear bit ========================== _Description_: `IBCLR' returns the value of I with the bit at position POS set to zero. _Standard_: F95 and later _Class_: Elemental function _Syntax_: `RESULT = IBCLR(I, POS)' _Arguments_: I The type shall be `INTEGER(*)'. POS The type shall be `INTEGER(*)'. _Return value_: The return value is of type `INTEGER(*)' and of the same kind as I. _See also_: *note IBITS::, *note IBSET::, *note IAND::, *note IOR::, *note IEOR::, *note MVBITS::  File: gfortran.info, Node: IBITS, Next: IBSET, Prev: IBCLR, Up: Intrinsic Procedures 6.102 `IBITS' -- Bit extraction =============================== _Description_: `IBITS' extracts a field of length LEN from I, starting from bit position POS and extending left for LEN bits. The result is right-justified and the remaining bits are zeroed. The value of `POS+LEN' must be less than or equal to the value `BIT_SIZE(I)'. _Standard_: F95 and later _Class_: Elemental function _Syntax_: `RESULT = IBITS(I, POS, LEN)' _Arguments_: I The type shall be `INTEGER(*)'. POS The type shall be `INTEGER(*)'. LEN The type shall be `INTEGER(*)'. _Return value_: The return value is of type `INTEGER(*)' and of the same kind as I. _See also_: *note BIT_SIZE::, *note IBCLR::, *note IBSET::, *note IAND::, *note IOR::, *note IEOR::  File: gfortran.info, Node: IBSET, Next: ICHAR, Prev: IBITS, Up: Intrinsic Procedures 6.103 `IBSET' -- Set bit ======================== _Description_: `IBSET' returns the value of I with the bit at position POS set to one. _Standard_: F95 and later _Class_: Elemental function _Syntax_: `RESULT = IBSET(I, POS)' _Arguments_: I The type shall be `INTEGER(*)'. POS The type shall be `INTEGER(*)'. _Return value_: The return value is of type `INTEGER(*)' and of the same kind as I. _See also_: *note IBCLR::, *note IBITS::, *note IAND::, *note IOR::, *note IEOR::, *note MVBITS::  File: gfortran.info, Node: ICHAR, Next: IDATE, Prev: IBSET, Up: Intrinsic Procedures 6.104 `ICHAR' -- Character-to-integer conversion function ========================================================= _Description_: `ICHAR(C)' returns the code for the character in the first character position of `C' in the system's native character set. The correspondence between characters and their codes is not necessarily the same across different GNU Fortran implementations. _Standard_: F95 and later _Class_: Elemental function _Syntax_: `RESULT = ICHAR(C [, KIND])' _Arguments_: C Shall be a scalar `CHARACTER', with `INTENT(IN)' KIND (Optional) An `INTEGER' initialization expression indicating the kind parameter of the result. _Return value_: The return value is of type `INTEGER' and of kind KIND. If KIND is absent, the return value is of default integer kind. _Example_: program test_ichar integer i i = ichar(' ') end program test_ichar _Note_: No intrinsic exists to convert between a numeric value and a formatted character string representation - for instance, given the `CHARACTER' value `'154'', obtaining an `INTEGER' or `REAL' value with the value 154, or vice versa. Instead, this functionality is provided by internal-file I/O, as in the following example: program read_val integer value character(len=10) string, string2 string = '154' ! Convert a string to a numeric value read (string,'(I10)') value print *, value ! Convert a value to a formatted string write (string2,'(I10)') value print *, string2 end program read_val _See also_: *note ACHAR::, *note CHAR::, *note IACHAR::  File: gfortran.info, Node: IDATE, Next: IEOR, Prev: ICHAR, Up: Intrinsic Procedures 6.105 `IDATE' -- Get current local time subroutine (day/month/year) =================================================================== _Description_: `IDATE(TARRAY)' Fills TARRAY with the numerical values at the current local time. The day (in the range 1-31), month (in the range 1-12), and year appear in elements 1, 2, and 3 of TARRAY, respectively. The year has four significant digits. _Standard_: GNU extension _Class_: Subroutine _Syntax_: `CALL IDATE(TARRAY)' _Arguments_: TARRAY The type shall be `INTEGER, DIMENSION(3)' and the kind shall be the default integer kind. _Return value_: Does not return. _Example_: program test_idate integer, dimension(3) :: tarray call idate(tarray) print *, tarray(1) print *, tarray(2) print *, tarray(3) end program test_idate  File: gfortran.info, Node: IEOR, Next: IERRNO, Prev: IDATE, Up: Intrinsic Procedures 6.106 `IEOR' -- Bitwise logical exclusive or ============================================ _Description_: `IEOR' returns the bitwise boolean exclusive-OR of I and J. _Standard_: F95 and later _Class_: Elemental function _Syntax_: `RESULT = IEOR(I, J)' _Arguments_: I The type shall be `INTEGER(*)'. J The type shall be `INTEGER(*)', of the same kind as I. (As a GNU extension, different kinds are also permitted.) _Return value_: The return type is `INTEGER(*)', of the same kind as the arguments. (If the argument kinds differ, it is of the same kind as the larger argument.) _See also_: *note IOR::, *note IAND::, *note IBITS::, *note IBSET::, *note IBCLR::, *note NOT::  File: gfortran.info, Node: IERRNO, Next: INDEX intrinsic, Prev: IEOR, Up: Intrinsic Procedures 6.107 `IERRNO' -- Get the last system error number ================================================== _Description_: Returns the last system error number, as given by the C `errno()' function. _Standard_: GNU extension _Class_: Function _Syntax_: `RESULT = IERRNO()' _Arguments_: None. _Return value_: The return value is of type `INTEGER' and of the default integer kind. _See also_: *note PERROR::  File: gfortran.info, Node: INDEX intrinsic, Next: INT, Prev: IERRNO, Up: Intrinsic Procedures 6.108 `INDEX' -- Position of a substring within a string ======================================================== _Description_: Returns the position of the start of the first occurrence of string SUBSTRING as a substring in STRING, counting from one. If SUBSTRING is not present in STRING, zero is returned. If the BACK argument is present and true, the return value is the start of the last occurrence rather than the first. _Standard_: F77 and later _Class_: Elemental function _Syntax_: `RESULT = INDEX(STRING, SUBSTRING [, BACK [, KIND]])' _Arguments_: STRING Shall be a scalar `CHARACTER(*)', with `INTENT(IN)' SUBSTRING Shall be a scalar `CHARACTER(*)', with `INTENT(IN)' BACK (Optional) Shall be a scalar `LOGICAL(*)', with `INTENT(IN)' KIND (Optional) An `INTEGER' initialization expression indicating the kind parameter of the result. _Return value_: The return value is of type `INTEGER' and of kind KIND. If KIND is absent, the return value is of default integer kind. _See also_: *note SCAN::, *note VERIFY::  File: gfortran.info, Node: INT, Next: INT2, Prev: INDEX intrinsic, Up: Intrinsic Procedures 6.109 `INT' -- Convert to integer type ====================================== _Description_: Convert to integer type _Standard_: F77 and later _Class_: Elemental function _Syntax_: `RESULT = INT(A [, KIND))' _Arguments_: A Shall be of type `INTEGER(*)', `REAL(*)', or `COMPLEX(*)'. KIND (Optional) An `INTEGER(*)' initialization expression indicating the kind parameter of the result. _Return value_: These functions return a `INTEGER(*)' variable or array under the following rules: (A) If A is of type `INTEGER(*)', `INT(A) = A' (B) If A is of type `REAL(*)' and |A| < 1, `INT(A)' equals `0'. If |A| \geq 1, then `INT(A)' equals the largest integer that does not exceed the range of A and whose sign is the same as the sign of A. (C) If A is of type `COMPLEX(*)', rule B is applied to the real part of A. _Example_: program test_int integer :: i = 42 complex :: z = (-3.7, 1.0) print *, int(i) print *, int(z), int(z,8) end program _Specific names_: Name Argument Return type Standard `IFIX(A)' `REAL(4) A' `INTEGER' F77 and later `IDINT(A)' `REAL(8) A' `INTEGER' F77 and later  File: gfortran.info, Node: INT2, Next: INT8, Prev: INT, Up: Intrinsic Procedures 6.110 `INT2' -- Convert to 16-bit integer type ============================================== _Description_: Convert to a `KIND=2' integer type. This is equivalent to the standard `INT' intrinsic with an optional argument of `KIND=2', and is only included for backwards compatibility. The `SHORT' intrinsic is equivalent to `INT2'. _Standard_: GNU extension. _Class_: Elemental function _Syntax_: `RESULT = INT2(A)' _Arguments_: A Shall be of type `INTEGER(*)', `REAL(*)', or `COMPLEX(*)'. _Return value_: The return value is a `INTEGER(2)' variable. _See also_: *note INT::, *note INT8::, *note LONG::  File: gfortran.info, Node: INT8, Next: IOR, Prev: INT2, Up: Intrinsic Procedures 6.111 `INT8' -- Convert to 64-bit integer type ============================================== _Description_: Convert to a `KIND=8' integer type. This is equivalent to the standard `INT' intrinsic with an optional argument of `KIND=8', and is only included for backwards compatibility. _Standard_: GNU extension. _Class_: Elemental function _Syntax_: `RESULT = INT8(A)' _Arguments_: A Shall be of type `INTEGER(*)', `REAL(*)', or `COMPLEX(*)'. _Return value_: The return value is a `INTEGER(8)' variable. _See also_: *note INT::, *note INT2::, *note LONG::  File: gfortran.info, Node: IOR, Next: IRAND, Prev: INT8, Up: Intrinsic Procedures 6.112 `IOR' -- Bitwise logical or ================================= _Description_: `IOR' returns the bitwise boolean inclusive-OR of I and J. _Standard_: F95 and later _Class_: Elemental function _Syntax_: `RESULT = IOR(I, J)' _Arguments_: I The type shall be `INTEGER(*)'. J The type shall be `INTEGER(*)', of the same kind as I. (As a GNU extension, different kinds are also permitted.) _Return value_: The return type is `INTEGER(*)', of the same kind as the arguments. (If the argument kinds differ, it is of the same kind as the larger argument.) _See also_: *note IEOR::, *note IAND::, *note IBITS::, *note IBSET::, *note IBCLR::, *note NOT::  File: gfortran.info, Node: IRAND, Next: IS_IOSTAT_END, Prev: IOR, Up: Intrinsic Procedures 6.113 `IRAND' -- Integer pseudo-random number ============================================= _Description_: `IRAND(FLAG)' returns a pseudo-random number from a uniform distribution between 0 and a system-dependent limit (which is in most cases 2147483647). If FLAG is 0, the next number in the current sequence is returned; if FLAG is 1, the generator is restarted by `CALL SRAND(0)'; if FLAG has any other value, it is used as a new seed with `SRAND'. This intrinsic routine is provided for backwards compatibility with GNU Fortran 77. It implements a simple modulo generator as provided by `g77'. For new code, one should consider the use of *note RANDOM_NUMBER:: as it implements a superior algorithm. _Standard_: GNU extension _Class_: Function _Syntax_: `RESULT = IRAND(FLAG)' _Arguments_: FLAG Shall be a scalar `INTEGER' of kind 4. _Return value_: The return value is of `INTEGER(kind=4)' type. _Example_: program test_irand integer,parameter :: seed = 86456 call srand(seed) print *, irand(), irand(), irand(), irand() print *, irand(seed), irand(), irand(), irand() end program test_irand  File: gfortran.info, Node: IS_IOSTAT_END, Next: IS_IOSTAT_EOR, Prev: IRAND, Up: Intrinsic Procedures 6.114 `IS_IOSTAT_END' -- Test for end-of-file value =================================================== _Description_: `IS_IOSTAT_END' tests whether an variable has the value of the I/O status "end of file". The function is equivalent to comparing the variable with the `IOSTAT_END' parameter of the intrinsic module `ISO_FORTRAN_ENV'. _Standard_: Fortran 2003. _Class_: Elemental function _Syntax_: `RESULT = IS_IOSTAT_END(I)' _Arguments_: I Shall be of the type `INTEGER'. _Return value_: Returns a `LOGICAL' of the default kind, which `.TRUE.' if I has the value which indicates an end of file condition for IOSTAT= specifiers, and is `.FALSE.' otherwise. _Example_: PROGRAM iostat IMPLICIT NONE INTEGER :: stat, i OPEN(88, FILE='test.dat') READ(88, *, IOSTAT=stat) i IF(IS_IOSTAT_END(stat)) STOP 'END OF FILE' END PROGRAM  File: gfortran.info, Node: IS_IOSTAT_EOR, Next: ISATTY, Prev: IS_IOSTAT_END, Up: Intrinsic Procedures 6.115 `IS_IOSTAT_EOR' -- Test for end-of-record value ===================================================== _Description_: `IS_IOSTAT_EOR' tests whether an variable has the value of the I/O status "end of record". The function is equivalent to comparing the variable with the `IOSTAT_EOR' parameter of the intrinsic module `ISO_FORTRAN_ENV'. _Standard_: Fortran 2003. _Class_: Elemental function _Syntax_: `RESULT = IS_IOSTAT_EOR(I)' _Arguments_: I Shall be of the type `INTEGER'. _Return value_: Returns a `LOGICAL' of the default kind, which `.TRUE.' if I has the value which indicates an end of file condition for IOSTAT= specifiers, and is `.FALSE.' otherwise. _Example_: PROGRAM iostat IMPLICIT NONE INTEGER :: stat, i(50) OPEN(88, FILE='test.dat', FORM='UNFORMATTED') READ(88, IOSTAT=stat) i IF(IS_IOSTAT_EOR(stat)) STOP 'END OF RECORD' END PROGRAM  File: gfortran.info, Node: ISATTY, Next: ISHFT, Prev: IS_IOSTAT_EOR, Up: Intrinsic Procedures 6.116 `ISATTY' -- Whether a unit is a terminal device. ====================================================== _Description_: Determine whether a unit is connected to a terminal device. _Standard_: GNU extension. _Class_: Function _Syntax_: `RESULT = ISATTY(UNIT)' _Arguments_: UNIT Shall be a scalar `INTEGER(*)'. _Return value_: Returns `.TRUE.' if the UNIT is connected to a terminal device, `.FALSE.' otherwise. _Example_: PROGRAM test_isatty INTEGER(kind=1) :: unit DO unit = 1, 10 write(*,*) isatty(unit=unit) END DO END PROGRAM _See also_: *note TTYNAM::  File: gfortran.info, Node: ISHFT, Next: ISHFTC, Prev: ISATTY, Up: Intrinsic Procedures 6.117 `ISHFT' -- Shift bits =========================== _Description_: `ISHFT' returns a value corresponding to I with all of the bits shifted SHIFT places. A value of SHIFT greater than zero corresponds to a left shift, a value of zero corresponds to no shift, and a value less than zero corresponds to a right shift. If the absolute value of SHIFT is greater than `BIT_SIZE(I)', the value is undefined. Bits shifted out from the left end or right end are lost; zeros are shifted in from the opposite end. _Standard_: F95 and later _Class_: Elemental function _Syntax_: `RESULT = ISHFT(I, SHIFT)' _Arguments_: I The type shall be `INTEGER(*)'. SHIFT The type shall be `INTEGER(*)'. _Return value_: The return value is of type `INTEGER(*)' and of the same kind as I. _See also_: *note ISHFTC::  File: gfortran.info, Node: ISHFTC, Next: ISNAN, Prev: ISHFT, Up: Intrinsic Procedures 6.118 `ISHFTC' -- Shift bits circularly ======================================= _Description_: `ISHFTC' returns a value corresponding to I with the rightmost SIZE bits shifted circularly SHIFT places; that is, bits shifted out one end are shifted into the opposite end. A value of SHIFT greater than zero corresponds to a left shift, a value of zero corresponds to no shift, and a value less than zero corresponds to a right shift. The absolute value of SHIFT must be less than SIZE. If the SIZE argument is omitted, it is taken to be equivalent to `BIT_SIZE(I)'. _Standard_: F95 and later _Class_: Elemental function _Syntax_: `RESULT = ISHFTC(I, SHIFT [, SIZE])' _Arguments_: I The type shall be `INTEGER(*)'. SHIFT The type shall be `INTEGER(*)'. SIZE (Optional) The type shall be `INTEGER(*)'; the value must be greater than zero and less than or equal to `BIT_SIZE(I)'. _Return value_: The return value is of type `INTEGER(*)' and of the same kind as I. _See also_: *note ISHFT::  File: gfortran.info, Node: ISNAN, Next: ITIME, Prev: ISHFTC, Up: Intrinsic Procedures 6.119 `ISNAN' -- Test for a NaN =============================== _Description_: `ISNAN' tests whether a floating-point value is an IEEE Not-a-Number (NaN). _Standard_: GNU extension _Class_: Elemental function _Syntax_: `ISNAN(X)' _Arguments_: X Variable of the type `REAL'. _Return value_: Returns a default-kind `LOGICAL'. The returned value is `TRUE' if X is a NaN and `FALSE' otherwise. _Example_: program test_nan implicit none real :: x x = -1.0 x = sqrt(x) if (isnan(x)) stop '"x" is a NaN' end program test_nan  File: gfortran.info, Node: ITIME, Next: KILL, Prev: ISNAN, Up: Intrinsic Procedures 6.120 `ITIME' -- Get current local time subroutine (hour/minutes/seconds) ========================================================================= _Description_: `IDATE(TARRAY)' Fills TARRAY with the numerical values at the current local time. The hour (in the range 1-24), minute (in the range 1-60), and seconds (in the range 1-60) appear in elements 1, 2, and 3 of TARRAY, respectively. _Standard_: GNU extension _Class_: Subroutine _Syntax_: `CALL ITIME(TARRAY)' _Arguments_: TARRAY The type shall be `INTEGER, DIMENSION(3)' and the kind shall be the default integer kind. _Return value_: Does not return. _Example_: program test_itime integer, dimension(3) :: tarray call itime(tarray) print *, tarray(1) print *, tarray(2) print *, tarray(3) end program test_itime  File: gfortran.info, Node: KILL, Next: KIND, Prev: ITIME, Up: Intrinsic Procedures 6.121 `KILL' -- Send a signal to a process ========================================== _Description_: _Standard_: Sends the signal specified by SIGNAL to the process PID. See `kill(2)'. This intrinsic is provided in both subroutine and function forms; however, only one form can be used in any given program unit. _Class_: Subroutine, function _Syntax_: `CALL KILL(PID, SIGNAL [, STATUS])' _Arguments_: PID Shall be a scalar `INTEGER', with `INTENT(IN)' SIGNAL Shall be a scalar `INTEGER', with `INTENT(IN)' STATUS (Optional) status flag of type `INTEGER(4)' or `INTEGER(8)'. Returns 0 on success, or a system-specific error code otherwise. _See also_: *note ABORT::, *note EXIT::  File: gfortran.info, Node: KIND, Next: LBOUND, Prev: KILL, Up: Intrinsic Procedures 6.122 `KIND' -- Kind of an entity ================================= _Description_: `KIND(X)' returns the kind value of the entity X. _Standard_: F95 and later _Class_: Inquiry function _Syntax_: `K = KIND(X)' _Arguments_: X Shall be of type `LOGICAL', `INTEGER', `REAL', `COMPLEX' or `CHARACTER'. _Return value_: The return value is a scalar of type `INTEGER' and of the default integer kind. _Example_: program test_kind integer,parameter :: kc = kind(' ') integer,parameter :: kl = kind(.true.) print *, "The default character kind is ", kc print *, "The default logical kind is ", kl end program test_kind  File: gfortran.info, Node: LBOUND, Next: LEN, Prev: KIND, Up: Intrinsic Procedures 6.123 `LBOUND' -- Lower dimension bounds of an array ==================================================== _Description_: Returns the lower bounds of an array, or a single lower bound along the DIM dimension. _Standard_: F95 and later _Class_: Inquiry function _Syntax_: `RESULT = LBOUND(ARRAY [, DIM [, KIND]])' _Arguments_: ARRAY Shall be an array, of any type. DIM (Optional) Shall be a scalar `INTEGER(*)'. KIND (Optional) An `INTEGER' initialization expression indicating the kind parameter of the result. _Return value_: The return value is of type `INTEGER' and of kind KIND. If KIND is absent, the return value is of default integer kind. If DIM is absent, the result is an array of the lower bounds of ARRAY. If DIM is present, the result is a scalar corresponding to the lower bound of the array along that dimension. If ARRAY is an expression rather than a whole array or array structure component, or if it has a zero extent along the relevant dimension, the lower bound is taken to be 1. _See also_: *note UBOUND::  File: gfortran.info, Node: LEN, Next: LEN_TRIM, Prev: LBOUND, Up: Intrinsic Procedures 6.124 `LEN' -- Length of a character entity =========================================== _Description_: Returns the length of a character string. If STRING is an array, the length of an element of STRING is returned. Note that STRING need not be defined when this intrinsic is invoked, since only the length, not the content, of STRING is needed. _Standard_: F77 and later _Class_: Inquiry function _Syntax_: `L = LEN(STRING [, KIND])' _Arguments_: STRING Shall be a scalar or array of type `CHARACTER(*)', with `INTENT(IN)' KIND (Optional) An `INTEGER' initialization expression indicating the kind parameter of the result. _Return value_: The return value is of type `INTEGER' and of kind KIND. If KIND is absent, the return value is of default integer kind. _See also_: *note LEN_TRIM::, *note ADJUSTL::, *note ADJUSTR::  File: gfortran.info, Node: LEN_TRIM, Next: LGAMMA, Prev: LEN, Up: Intrinsic Procedures 6.125 `LEN_TRIM' -- Length of a character entity without trailing blank characters ================================================================================== _Description_: Returns the length of a character string, ignoring any trailing blanks. _Standard_: F95 and later _Class_: Elemental function _Syntax_: `RESULT = LEN_TRIM(STRING [, KIND])' _Arguments_: STRING Shall be a scalar of type `CHARACTER(*)', with `INTENT(IN)' KIND (Optional) An `INTEGER' initialization expression indicating the kind parameter of the result. _Return value_: The return value is of type `INTEGER' and of kind KIND. If KIND is absent, the return value is of default integer kind. _See also_: *note LEN::, *note ADJUSTL::, *note ADJUSTR::  File: gfortran.info, Node: LGAMMA, Next: LGE, Prev: LEN_TRIM, Up: Intrinsic Procedures 6.126 `LGAMMA' -- Logarithm of the Gamma function ================================================= _Description_: `GAMMA(X)' computes the natural logrithm of the absolute value of the Gamma (\Gamma) function. _Standard_: GNU Extension _Class_: Elemental function _Syntax_: `X = LGAMMA(X)' _Arguments_: X Shall be of type `REAL' and neither zero nor a negative integer. _Return value_: The return value is of type `REAL' of the same kind as X. _Example_: program test_log_gamma real :: x = 1.0 x = lgamma(x) ! returns 0.0 end program test_log_gamma _Specific names_: Name Argument Return type Standard `LGAMMA(X)' `REAL(4) X' `REAL(4)' GNU Extension `ALGAMA(X)' `REAL(4) X' `REAL(4)' GNU Extension `DLGAMA(X)' `REAL(8) X' `REAL(8)' GNU Extension _See also_: Gamma function: *note GAMMA::  File: gfortran.info, Node: LGE, Next: LGT, Prev: LGAMMA, Up: Intrinsic Procedures 6.127 `LGE' -- Lexical greater than or equal ============================================ _Description_: Determines whether one string is lexically greater than or equal to another string, where the two strings are interpreted as containing ASCII character codes. If the String A and String B are not the same length, the shorter is compared as if spaces were appended to it to form a value that has the same length as the longer. In general, the lexical comparison intrinsics `LGE', `LGT', `LLE', and `LLT' differ from the corresponding intrinsic operators `.GE.', `.GT.', `.LE.', and `.LT.', in that the latter use the processor's character ordering (which is not ASCII on some targets), whereas the former always use the ASCII ordering. _Standard_: F77 and later _Class_: Elemental function _Syntax_: `RESULT = LGE(STRING_A, STRING_B)' _Arguments_: STRING_A Shall be of default `CHARACTER' type. STRING_B Shall be of default `CHARACTER' type. _Return value_: Returns `.TRUE.' if `STRING_A >= STRING_B', and `.FALSE.' otherwise, based on the ASCII ordering. _See also_: *note LGT::, *note LLE::, *note LLT::  File: gfortran.info, Node: LGT, Next: LINK, Prev: LGE, Up: Intrinsic Procedures 6.128 `LGT' -- Lexical greater than =================================== _Description_: Determines whether one string is lexically greater than another string, where the two strings are interpreted as containing ASCII character codes. If the String A and String B are not the same length, the shorter is compared as if spaces were appended to it to form a value that has the same length as the longer. In general, the lexical comparison intrinsics `LGE', `LGT', `LLE', and `LLT' differ from the corresponding intrinsic operators `.GE.', `.GT.', `.LE.', and `.LT.', in that the latter use the processor's character ordering (which is not ASCII on some targets), whereas the former always use the ASCII ordering. _Standard_: F77 and later _Class_: Elemental function _Syntax_: `RESULT = LGT(STRING_A, STRING_B)' _Arguments_: STRING_A Shall be of default `CHARACTER' type. STRING_B Shall be of default `CHARACTER' type. _Return value_: Returns `.TRUE.' if `STRING_A > STRING_B', and `.FALSE.' otherwise, based on the ASCII ordering. _See also_: *note LGE::, *note LLE::, *note LLT::  File: gfortran.info, Node: LINK, Next: LLE, Prev: LGT, Up: Intrinsic Procedures 6.129 `LINK' -- Create a hard link ================================== _Description_: Makes a (hard) link from file PATH1 to PATH2. A null character (`CHAR(0)') can be used to mark the end of the names in PATH1 and PATH2; otherwise, trailing blanks in the file names are ignored. If the STATUS argument is supplied, it contains 0 on success or a nonzero error code upon return; see `link(2)'. This intrinsic is provided in both subroutine and function forms; however, only one form can be used in any given program unit. _Standard_: GNU extension _Class_: Subroutine, function _Syntax_: `CALL LINK(PATH1, PATH2 [, STATUS])' `STATUS = LINK(PATH1, PATH2)' _Arguments_: PATH1 Shall be of default `CHARACTER' type. PATH2 Shall be of default `CHARACTER' type. STATUS (Optional) Shall be of default `INTEGER' type. _See also_: *note SYMLNK::, *note UNLINK::  File: gfortran.info, Node: LLE, Next: LLT, Prev: LINK, Up: Intrinsic Procedures 6.130 `LLE' -- Lexical less than or equal ========================================= _Description_: Determines whether one string is lexically less than or equal to another string, where the two strings are interpreted as containing ASCII character codes. If the String A and String B are not the same length, the shorter is compared as if spaces were appended to it to form a value that has the same length as the longer. In general, the lexical comparison intrinsics `LGE', `LGT', `LLE', and `LLT' differ from the corresponding intrinsic operators `.GE.', `.GT.', `.LE.', and `.LT.', in that the latter use the processor's character ordering (which is not ASCII on some targets), whereas the former always use the ASCII ordering. _Standard_: F77 and later _Class_: Elemental function _Syntax_: `RESULT = LLE(STRING_A, STRING_B)' _Arguments_: STRING_A Shall be of default `CHARACTER' type. STRING_B Shall be of default `CHARACTER' type. _Return value_: Returns `.TRUE.' if `STRING_A <= STRING_B', and `.FALSE.' otherwise, based on the ASCII ordering. _See also_: *note LGE::, *note LGT::, *note LLT::  File: gfortran.info, Node: LLT, Next: LNBLNK, Prev: LLE, Up: Intrinsic Procedures 6.131 `LLT' -- Lexical less than ================================ _Description_: Determines whether one string is lexically less than another string, where the two strings are interpreted as containing ASCII character codes. If the String A and String B are not the same length, the shorter is compared as if spaces were appended to it to form a value that has the same length as the longer. In general, the lexical comparison intrinsics `LGE', `LGT', `LLE', and `LLT' differ from the corresponding intrinsic operators `.GE.', `.GT.', `.LE.', and `.LT.', in that the latter use the processor's character ordering (which is not ASCII on some targets), whereas the former always use the ASCII ordering. _Standard_: F77 and later _Class_: Elemental function _Syntax_: `RESULT = LLT(STRING_A, STRING_B)' _Arguments_: STRING_A Shall be of default `CHARACTER' type. STRING_B Shall be of default `CHARACTER' type. _Return value_: Returns `.TRUE.' if `STRING_A < STRING_B', and `.FALSE.' otherwise, based on the ASCII ordering. _See also_: *note LGE::, *note LGT::, *note LLE::  File: gfortran.info, Node: LNBLNK, Next: LOC, Prev: LLT, Up: Intrinsic Procedures 6.132 `LNBLNK' -- Index of the last non-blank character in a string =================================================================== _Description_: Returns the length of a character string, ignoring any trailing blanks. This is identical to the standard `LEN_TRIM' intrinsic, and is only included for backwards compatibility. _Standard_: GNU extension _Class_: Elemental function _Syntax_: `RESULT = LNBLNK(STRING)' _Arguments_: STRING Shall be a scalar of type `CHARACTER(*)', with `INTENT(IN)' _Return value_: The return value is of `INTEGER(kind=4)' type. _See also_: *note INDEX intrinsic::, *note LEN_TRIM::  File: gfortran.info, Node: LOC, Next: LOG, Prev: LNBLNK, Up: Intrinsic Procedures 6.133 `LOC' -- Returns the address of a variable ================================================ _Description_: `LOC(X)' returns the address of X as an integer. _Standard_: GNU extension _Class_: Inquiry function _Syntax_: `RESULT = LOC(X)' _Arguments_: X Variable of any type. _Return value_: The return value is of type `INTEGER', with a `KIND' corresponding to the size (in bytes) of a memory address on the target machine. _Example_: program test_loc integer :: i real :: r i = loc(r) print *, i end program test_loc  File: gfortran.info, Node: LOG, Next: LOG10, Prev: LOC, Up: Intrinsic Procedures 6.134 `LOG' -- Logarithm function ================================= _Description_: `LOG(X)' computes the logarithm of X. _Standard_: F77 and later _Class_: Elemental function _Syntax_: `RESULT = LOG(X)' _Arguments_: X The type shall be `REAL(*)' or `COMPLEX(*)'. _Return value_: The return value is of type `REAL(*)' or `COMPLEX(*)'. The kind type parameter is the same as X. _Example_: program test_log real(8) :: x = 1.0_8 complex :: z = (1.0, 2.0) x = log(x) z = log(z) end program test_log _Specific names_: Name Argument Return type Standard `ALOG(X)' `REAL(4) X' `REAL(4)' f95, gnu `DLOG(X)' `REAL(8) X' `REAL(8)' f95, gnu `CLOG(X)' `COMPLEX(4) `COMPLEX(4)' f95, gnu X' `ZLOG(X)' `COMPLEX(8) `COMPLEX(8)' f95, gnu X' `CDLOG(X)' `COMPLEX(8) `COMPLEX(8)' f95, gnu X'  File: gfortran.info, Node: LOG10, Next: LOGICAL, Prev: LOG, Up: Intrinsic Procedures 6.135 `LOG10' -- Base 10 logarithm function =========================================== _Description_: `LOG10(X)' computes the base 10 logarithm of X. _Standard_: F77 and later _Class_: Elemental function _Syntax_: `RESULT = LOG10(X)' _Arguments_: X The type shall be `REAL(*)'. _Return value_: The return value is of type `REAL(*)' or `COMPLEX(*)'. The kind type parameter is the same as X. _Example_: program test_log10 real(8) :: x = 10.0_8 x = log10(x) end program test_log10 _Specific names_: Name Argument Return type Standard `ALOG10(X)' `REAL(4) X' `REAL(4)' F95 and later `DLOG10(X)' `REAL(8) X' `REAL(8)' F95 and later  File: gfortran.info, Node: LOGICAL, Next: LONG, Prev: LOG10, Up: Intrinsic Procedures 6.136 `LOGICAL' -- Convert to logical type ========================================== _Description_: Converts one kind of `LOGICAL' variable to another. _Standard_: F95 and later _Class_: Elemental function _Syntax_: `RESULT = LOGICAL(L [, KIND])' _Arguments_: L The type shall be `LOGICAL(*)'. KIND (Optional) An `INTEGER(*)' initialization expression indicating the kind parameter of the result. _Return value_: The return value is a `LOGICAL' value equal to L, with a kind corresponding to KIND, or of the default logical kind if KIND is not given. _See also_: *note INT::, *note REAL::, *note CMPLX::  File: gfortran.info, Node: LONG, Next: LSHIFT, Prev: LOGICAL, Up: Intrinsic Procedures 6.137 `LONG' -- Convert to integer type ======================================= _Description_: Convert to a `KIND=4' integer type, which is the same size as a C `long' integer. This is equivalent to the standard `INT' intrinsic with an optional argument of `KIND=4', and is only included for backwards compatibility. _Standard_: GNU extension. _Class_: Elemental function _Syntax_: `RESULT = LONG(A)' _Arguments_: A Shall be of type `INTEGER(*)', `REAL(*)', or `COMPLEX(*)'. _Return value_: The return value is a `INTEGER(4)' variable. _See also_: *note INT::, *note INT2::, *note INT8::  File: gfortran.info, Node: LSHIFT, Next: LSTAT, Prev: LONG, Up: Intrinsic Procedures 6.138 `LSHIFT' -- Left shift bits ================================= _Description_: `LSHIFT' returns a value corresponding to I with all of the bits shifted left by SHIFT places. If the absolute value of SHIFT is greater than `BIT_SIZE(I)', the value is undefined. Bits shifted out from the left end are lost; zeros are shifted in from the opposite end. This function has been superseded by the `ISHFT' intrinsic, which is standard in Fortran 95 and later. _Standard_: GNU extension _Class_: Elemental function _Syntax_: `RESULT = LSHIFT(I, SHIFT)' _Arguments_: I The type shall be `INTEGER(*)'. SHIFT The type shall be `INTEGER(*)'. _Return value_: The return value is of type `INTEGER(*)' and of the same kind as I. _See also_: *note ISHFT::, *note ISHFTC::, *note RSHIFT::  File: gfortran.info, Node: LSTAT, Next: LTIME, Prev: LSHIFT, Up: Intrinsic Procedures 6.139 `LSTAT' -- Get file status ================================ _Description_: `LSTAT' is identical to *note STAT::, except that if path is a symbolic link, then the link itself is statted, not the file that it refers to. The elements in `BUFF' are the same as described by *note STAT::. This intrinsic is provided in both subroutine and function forms; however, only one form can be used in any given program unit. _Standard_: GNU extension _Class_: Subroutine, function _Syntax_: `CALL LSTAT(FILE, BUFF [, STATUS])' _Arguments_: FILE The type shall be `CHARACTER(*)', a valid path within the file system. BUFF The type shall be `INTEGER(4), DIMENSION(13)'. STATUS (Optional) status flag of type `INTEGER(4)'. Returns 0 on success and a system specific error code otherwise. _Example_: See *note STAT:: for an example. _See also_: To stat an open file: *note FSTAT::, to stat a file: *note STAT::  File: gfortran.info, Node: LTIME, Next: MALLOC, Prev: LSTAT, Up: Intrinsic Procedures 6.140 `LTIME' -- Convert time to local time info ================================================ _Description_: Given a system time value STIME (as provided by the `TIME8()' intrinsic), fills TARRAY with values extracted from it appropriate to the local time zone using `localtime(3)'. _Standard_: GNU extension _Class_: Subroutine _Syntax_: `CALL LTIME(STIME, TARRAY)' _Arguments_: STIME An `INTEGER(*)' scalar expression corresponding to a system time, with `INTENT(IN)'. TARRAY A default `INTEGER' array with 9 elements, with `INTENT(OUT)'. _Return value_: The elements of TARRAY are assigned as follows: 1. Seconds after the minute, range 0-59 or 0-61 to allow for leap seconds 2. Minutes after the hour, range 0-59 3. Hours past midnight, range 0-23 4. Day of month, range 0-31 5. Number of months since January, range 0-12 6. Years since 1900 7. Number of days since Sunday, range 0-6 8. Days since January 1 9. Daylight savings indicator: positive if daylight savings is in effect, zero if not, and negative if the information is not available. _See also_: *note CTIME::, *note GMTIME::, *note TIME::, *note TIME8::  File: gfortran.info, Node: MALLOC, Next: MATMUL, Prev: LTIME, Up: Intrinsic Procedures 6.141 `MALLOC' -- Allocate dynamic memory ========================================= _Description_: `MALLOC(SIZE)' allocates SIZE bytes of dynamic memory and returns the address of the allocated memory. The `MALLOC' intrinsic is an extension intended to be used with Cray pointers, and is provided in GNU Fortran to allow the user to compile legacy code. For new code using Fortran 95 pointers, the memory allocation intrinsic is `ALLOCATE'. _Standard_: GNU extension _Class_: Function _Syntax_: `PTR = MALLOC(SIZE)' _Arguments_: SIZE The type shall be `INTEGER(*)'. _Return value_: The return value is of type `INTEGER(K)', with K such that variables of type `INTEGER(K)' have the same size as C pointers (`sizeof(void *)'). _Example_: The following example demonstrates the use of `MALLOC' and `FREE' with Cray pointers. This example is intended to run on 32-bit systems, where the default integer kind is suitable to store pointers; on 64-bit systems, ptr_x would need to be declared as `integer(kind=8)'. program test_malloc integer i integer ptr_x real*8 x(*), z pointer(ptr_x,x) ptr_x = malloc(20*8) do i = 1, 20 x(i) = sqrt(1.0d0 / i) end do z = 0 do i = 1, 20 z = z + x(i) print *, z end do call free(ptr_x) end program test_malloc _See also_: *note FREE::  File: gfortran.info, Node: MATMUL, Next: MAX, Prev: MALLOC, Up: Intrinsic Procedures 6.142 `MATMUL' -- matrix multiplication ======================================= _Description_: Performs a matrix multiplication on numeric or logical arguments. _Standard_: F95 and later _Class_: Transformational function _Syntax_: `RESULT = MATMUL(MATRIX_A, MATRIX_B)' _Arguments_: MATRIX_A An array of `INTEGER(*)', `REAL(*)', `COMPLEX(*)', or `LOGICAL(*)' type, with a rank of one or two. MATRIX_B An array of `INTEGER(*)', `REAL(*)', or `COMPLEX(*)' type if MATRIX_A is of a numeric type; otherwise, an array of `LOGICAL(*)' type. The rank shall be one or two, and the first (or only) dimension of MATRIX_B shall be equal to the last (or only) dimension of MATRIX_A. _Return value_: The matrix product of MATRIX_A and MATRIX_B. The type and kind of the result follow the usual type and kind promotion rules, as for the `*' or `.AND.' operators. _See also_:  File: gfortran.info, Node: MAX, Next: MAXEXPONENT, Prev: MATMUL, Up: Intrinsic Procedures 6.143 `MAX' -- Maximum value of an argument list ================================================ _Description_: Returns the argument with the largest (most positive) value. _Standard_: F77 and later _Class_: Elemental function _Syntax_: `RESULT = MAX(A1, A2 [, A3 [, ...]])' _Arguments_: A1 The type shall be `INTEGER(*)' or `REAL(*)'. A2, A3, An expression of the same type and kind ... as A1. (As a GNU extension, arguments of different kinds are permitted.) _Return value_: The return value corresponds to the maximum value among the arguments, and has the same type and kind as the first argument. _Specific names_: Name Argument Return type Standard `MAX0(I)' `INTEGER(4) `INTEGER(4)' F77 and later I' `AMAX0(I)' `INTEGER(4) `REAL(MAX(X))'F77 and later I' `MAX1(X)' `REAL(*) X' `INT(MAX(X))' F77 and later `AMAX1(X)' `REAL(4) `REAL(4)' F77 and later X' `DMAX1(X)' `REAL(8) `REAL(8)' F77 and later X' _See also_: *note MAXLOC:: *note MAXVAL::, *note MIN::  File: gfortran.info, Node: MAXEXPONENT, Next: MAXLOC, Prev: MAX, Up: Intrinsic Procedures 6.144 `MAXEXPONENT' -- Maximum exponent of a real kind ====================================================== _Description_: `MAXEXPONENT(X)' returns the maximum exponent in the model of the type of `X'. _Standard_: F95 and later _Class_: Inquiry function _Syntax_: `RESULT = MAXEXPONENT(X)' _Arguments_: X Shall be of type `REAL'. _Return value_: The return value is of type `INTEGER' and of the default integer kind. _Example_: program exponents real(kind=4) :: x real(kind=8) :: y print *, minexponent(x), maxexponent(x) print *, minexponent(y), maxexponent(y) end program exponents  File: gfortran.info, Node: MAXLOC, Next: MAXVAL, Prev: MAXEXPONENT, Up: Intrinsic Procedures 6.145 `MAXLOC' -- Location of the maximum value within an array =============================================================== _Description_: Determines the location of the element in the array with the maximum value, or, if the DIM argument is supplied, determines the locations of the maximum element along each row of the array in the DIM direction. If MASK is present, only the elements for which MASK is `.TRUE.' are considered. If more than one element in the array has the maximum value, the location returned is that of the first such element in array element order. If the array has zero size, or all of the elements of MASK are `.FALSE.', then the result is an array of zeroes. Similarly, if DIM is supplied and all of the elements of MASK along a given row are zero, the result value for that row is zero. _Standard_: F95 and later _Class_: Transformational function _Syntax_: `RESULT = MAXLOC(ARRAY, DIM [, MASK])' `RESULT = MAXLOC(ARRAY [, MASK])' _Arguments_: ARRAY Shall be an array of type `INTEGER(*)', `REAL(*)', or `CHARACTER(*)'. DIM (Optional) Shall be a scalar of type `INTEGER(*)', with a value between one and the rank of ARRAY, inclusive. It may not be an optional dummy argument. MASK Shall be an array of type `LOGICAL(*)', and conformable with ARRAY. _Return value_: If DIM is absent, the result is a rank-one array with a length equal to the rank of ARRAY. If DIM is present, the result is an array with a rank one less than the rank of ARRAY, and a size corresponding to the size of ARRAY with the DIM dimension removed. If DIM is present and ARRAY has a rank of one, the result is a scalar. In all cases, the result is of default `INTEGER' type. _See also_: *note MAX::, *note MAXVAL::  File: gfortran.info, Node: MAXVAL, Next: MCLOCK, Prev: MAXLOC, Up: Intrinsic Procedures 6.146 `MAXVAL' -- Maximum value of an array =========================================== _Description_: Determines the maximum value of the elements in an array value, or, if the DIM argument is supplied, determines the maximum value along each row of the array in the DIM direction. If MASK is present, only the elements for which MASK is `.TRUE.' are considered. If the array has zero size, or all of the elements of MASK are `.FALSE.', then the result is the most negative number of the type and kind of ARRAY if ARRAY is numeric, or a string of nulls if ARRAY is of character type. _Standard_: F95 and later _Class_: Transformational function _Syntax_: `RESULT = MAXVAL(ARRAY, DIM [, MASK])' `RESULT = MAXVAL(ARRAY [, MASK])' _Arguments_: ARRAY Shall be an array of type `INTEGER(*)', `REAL(*)', or `CHARACTER(*)'. DIM (Optional) Shall be a scalar of type `INTEGER(*)', with a value between one and the rank of ARRAY, inclusive. It may not be an optional dummy argument. MASK Shall be an array of type `LOGICAL(*)', and conformable with ARRAY. _Return value_: If DIM is absent, or if ARRAY has a rank of one, the result is a scalar. If DIM is present, the result is an array with a rank one less than the rank of ARRAY, and a size corresponding to the size of ARRAY with the DIM dimension removed. In all cases, the result is of the same type and kind as ARRAY. _See also_: *note MAX::, *note MAXLOC::  File: gfortran.info, Node: MCLOCK, Next: MCLOCK8, Prev: MAXVAL, Up: Intrinsic Procedures 6.147 `MCLOCK' -- Time function =============================== _Description_: Returns the number of clock ticks since the start of the process, based on the UNIX function `clock(3)'. This intrinsic is not fully portable, such as to systems with 32-bit `INTEGER' types but supporting times wider than 32 bits. Therefore, the values returned by this intrinsic might be, or become, negative, or numerically less than previous values, during a single run of the compiled program. _Standard_: GNU extension _Class_: Function _Syntax_: `RESULT = MCLOCK()' _Return value_: The return value is a scalar of type `INTEGER(4)', equal to the number of clock ticks since the start of the process, or `-1' if the system does not support `clock(3)'. _See also_: *note CTIME::, *note GMTIME::, *note LTIME::, *note MCLOCK::, *note TIME::  File: gfortran.info, Node: MCLOCK8, Next: MERGE, Prev: MCLOCK, Up: Intrinsic Procedures 6.148 `MCLOCK8' -- Time function (64-bit) ========================================= _Description_: Returns the number of clock ticks since the start of the process, based on the UNIX function `clock(3)'. _Warning:_ this intrinsic does not increase the range of the timing values over that returned by `clock(3)'. On a system with a 32-bit `clock(3)', `MCLOCK8()' will return a 32-bit value, even though it is converted to a 64-bit `INTEGER(8)' value. That means overflows of the 32-bit value can still occur. Therefore, the values returned by this intrinsic might be or become negative or numerically less than previous values during a single run of the compiled program. _Standard_: GNU extension _Class_: Function _Syntax_: `RESULT = MCLOCK8()' _Return value_: The return value is a scalar of type `INTEGER(8)', equal to the number of clock ticks since the start of the process, or `-1' if the system does not support `clock(3)'. _See also_: *note CTIME::, *note GMTIME::, *note LTIME::, *note MCLOCK::, *note TIME8::  File: gfortran.info, Node: MERGE, Next: MIN, Prev: MCLOCK8, Up: Intrinsic Procedures 6.149 `MERGE' -- Merge variables ================================ _Description_: Select values from two arrays according to a logical mask. The result is equal to TSOURCE if MASK is `.TRUE.', or equal to FSOURCE if it is `.FALSE.'. _Standard_: F95 and later _Class_: Elemental function _Syntax_: `RESULT = MERGE(TSOURCE, FSOURCE, MASK)' _Arguments_: TSOURCE May be of any type. FSOURCE Shall be of the same type and type parameters as TSOURCE. MASK Shall be of type `LOGICAL(*)'. _Return value_: The result is of the same type and type parameters as TSOURCE.  File: gfortran.info, Node: MIN, Next: MINEXPONENT, Prev: MERGE, Up: Intrinsic Procedures 6.150 `MIN' -- Minimum value of an argument list ================================================ _Description_: Returns the argument with the smallest (most negative) value. _Standard_: F77 and later _Class_: Elemental function _Syntax_: `RESULT = MIN(A1, A2 [, A3, ...])' _Arguments_: A1 The type shall be `INTEGER(*)' or `REAL(*)'. A2, A3, An expression of the same type and kind ... as A1. (As a GNU extension, arguments of different kinds are permitted.) _Return value_: The return value corresponds to the maximum value among the arguments, and has the same type and kind as the first argument. _Specific names_: Name Argument Return type Standard `MIN0(I)' `INTEGER(4) `INTEGER(4)' F77 and later I' `AMIN0(I)' `INTEGER(4) `REAL(MIN(X))'F77 and later I' `MIN1(X)' `REAL(*) X' `INT(MIN(X))' F77 and later `AMIN1(X)' `REAL(4) `REAL(4)' F77 and later X' `DMIN1(X)' `REAL(8) `REAL(8)' F77 and later X' _See also_: *note MAX::, *note MINLOC::, *note MINVAL::  File: gfortran.info, Node: MINEXPONENT, Next: MINLOC, Prev: MIN, Up: Intrinsic Procedures 6.151 `MINEXPONENT' -- Minimum exponent of a real kind ====================================================== _Description_: `MINEXPONENT(X)' returns the minimum exponent in the model of the type of `X'. _Standard_: F95 and later _Class_: Inquiry function _Syntax_: `RESULT = MINEXPONENT(X)' _Arguments_: X Shall be of type `REAL'. _Return value_: The return value is of type `INTEGER' and of the default integer kind. _Example_: See `MAXEXPONENT' for an example.  File: gfortran.info, Node: MINLOC, Next: MINVAL, Prev: MINEXPONENT, Up: Intrinsic Procedures 6.152 `MINLOC' -- Location of the minimum value within an array =============================================================== _Description_: Determines the location of the element in the array with the minimum value, or, if the DIM argument is supplied, determines the locations of the minimum element along each row of the array in the DIM direction. If MASK is present, only the elements for which MASK is `.TRUE.' are considered. If more than one element in the array has the minimum value, the location returned is that of the first such element in array element order. If the array has zero size, or all of the elements of MASK are `.FALSE.', then the result is an array of zeroes. Similarly, if DIM is supplied and all of the elements of MASK along a given row are zero, the result value for that row is zero. _Standard_: F95 and later _Class_: Transformational function _Syntax_: `RESULT = MINLOC(ARRAY, DIM [, MASK])' `RESULT = MINLOC(ARRAY [, MASK])' _Arguments_: ARRAY Shall be an array of type `INTEGER(*)', `REAL(*)', or `CHARACTER(*)'. DIM (Optional) Shall be a scalar of type `INTEGER(*)', with a value between one and the rank of ARRAY, inclusive. It may not be an optional dummy argument. MASK Shall be an array of type `LOGICAL(*)', and conformable with ARRAY. _Return value_: If DIM is absent, the result is a rank-one array with a length equal to the rank of ARRAY. If DIM is present, the result is an array with a rank one less than the rank of ARRAY, and a size corresponding to the size of ARRAY with the DIM dimension removed. If DIM is present and ARRAY has a rank of one, the result is a scalar. In all cases, the result is of default `INTEGER' type. _See also_: *note MIN::, *note MINVAL::  File: gfortran.info, Node: MINVAL, Next: MOD, Prev: MINLOC, Up: Intrinsic Procedures 6.153 `MINVAL' -- Minimum value of an array =========================================== _Description_: Determines the minimum value of the elements in an array value, or, if the DIM argument is supplied, determines the minimum value along each row of the array in the DIM direction. If MASK is present, only the elements for which MASK is `.TRUE.' are considered. If the array has zero size, or all of the elements of MASK are `.FALSE.', then the result is `HUGE(ARRAY)' if ARRAY is numeric, or a string of `CHAR(255)' characters if ARRAY is of character type. _Standard_: F95 and later _Class_: Transformational function _Syntax_: `RESULT = MINVAL(ARRAY, DIM [, MASK])' `RESULT = MINVAL(ARRAY [, MASK])' _Arguments_: ARRAY Shall be an array of type `INTEGER(*)', `REAL(*)', or `CHARACTER(*)'. DIM (Optional) Shall be a scalar of type `INTEGER(*)', with a value between one and the rank of ARRAY, inclusive. It may not be an optional dummy argument. MASK Shall be an array of type `LOGICAL(*)', and conformable with ARRAY. _Return value_: If DIM is absent, or if ARRAY has a rank of one, the result is a scalar. If DIM is present, the result is an array with a rank one less than the rank of ARRAY, and a size corresponding to the size of ARRAY with the DIM dimension removed. In all cases, the result is of the same type and kind as ARRAY. _See also_: *note MIN::, *note MINLOC::  File: gfortran.info, Node: MOD, Next: MODULO, Prev: MINVAL, Up: Intrinsic Procedures 6.154 `MOD' -- Remainder function ================================= _Description_: `MOD(A,P)' computes the remainder of the division of A by P. It is calculated as `A - (INT(A/P) * P)'. _Standard_: F77 and later _Class_: Elemental function _Syntax_: `RESULT = MOD(A, P)' _Arguments_: A Shall be a scalar of type `INTEGER' or `REAL' P Shall be a scalar of the same type as A and not equal to zero _Return value_: The kind of the return value is the result of cross-promoting the kinds of the arguments. _Example_: program test_mod print *, mod(17,3) print *, mod(17.5,5.5) print *, mod(17.5d0,5.5) print *, mod(17.5,5.5d0) print *, mod(-17,3) print *, mod(-17.5,5.5) print *, mod(-17.5d0,5.5) print *, mod(-17.5,5.5d0) print *, mod(17,-3) print *, mod(17.5,-5.5) print *, mod(17.5d0,-5.5) print *, mod(17.5,-5.5d0) end program test_mod _Specific names_: Name Arguments Return type Standard `AMOD(A,P)' `REAL(4)' `REAL(4)' F95 and later `DMOD(A,P)' `REAL(8)' `REAL(8)' F95 and later  File: gfortran.info, Node: MODULO, Next: MOVE_ALLOC, Prev: MOD, Up: Intrinsic Procedures 6.155 `MODULO' -- Modulo function ================================= _Description_: `MODULO(A,P)' computes the A modulo P. _Standard_: F95 and later _Class_: Elemental function _Syntax_: `RESULT = MODULO(A, P)' _Arguments_: A Shall be a scalar of type `INTEGER' or `REAL' P Shall be a scalar of the same type and kind as A _Return value_: The type and kind of the result are those of the arguments. If A and P are of type `INTEGER': `MODULO(A,P)' has the value R such that `A=Q*P+R', where Q is an integer and R is between 0 (inclusive) and P (exclusive). If A and P are of type `REAL': `MODULO(A,P)' has the value of `A - FLOOR (A / P) * P'. In all cases, if P is zero the result is processor-dependent. _Example_: program test_modulo print *, modulo(17,3) print *, modulo(17.5,5.5) print *, modulo(-17,3) print *, modulo(-17.5,5.5) print *, modulo(17,-3) print *, modulo(17.5,-5.5) end program  File: gfortran.info, Node: MOVE_ALLOC, Next: MVBITS, Prev: MODULO, Up: Intrinsic Procedures 6.156 `MOVE_ALLOC' -- Move allocation from one object to another ================================================================ _Description_: `MOVE_ALLOC(SRC, DEST)' moves the allocation from SRC to DEST. SRC will become deallocated in the process. _Standard_: F2003 and later _Class_: Subroutine _Syntax_: `CALL MOVE_ALLOC(SRC, DEST)' _Arguments_: SRC `ALLOCATABLE', `INTENT(INOUT)', may be of any type and kind. DEST `ALLOCATABLE', `INTENT(OUT)', shall be of the same type, kind and rank as SRC _Return value_: None _Example_: program test_move_alloc integer, allocatable :: a(:), b(:) allocate(a(3)) a = [ 1, 2, 3 ] call move_alloc(a, b) print *, allocated(a), allocated(b) print *, b end program test_move_alloc  File: gfortran.info, Node: MVBITS, Next: NEAREST, Prev: MOVE_ALLOC, Up: Intrinsic Procedures 6.157 `MVBITS' -- Move bits from one integer to another ======================================================= _Description_: Moves LEN bits from positions FROMPOS through `FROMPOS+LEN-1' of FROM to positions TOPOS through `TOPOS+LEN-1' of TO. The portion of argument TO not affected by the movement of bits is unchanged. The values of `FROMPOS+LEN-1' and `TOPOS+LEN-1' must be less than `BIT_SIZE(FROM)'. _Standard_: F95 and later _Class_: Elemental subroutine _Syntax_: `CALL MVBITS(FROM, FROMPOS, LEN, TO, TOPOS)' _Arguments_: FROM The type shall be `INTEGER(*)'. FROMPOS The type shall be `INTEGER(*)'. LEN The type shall be `INTEGER(*)'. TO The type shall be `INTEGER(*)', of the same kind as FROM. TOPOS The type shall be `INTEGER(*)'. _See also_: *note IBCLR::, *note IBSET::, *note IBITS::, *note IAND::, *note IOR::, *note IEOR::  File: gfortran.info, Node: NEAREST, Next: NEW_LINE, Prev: MVBITS, Up: Intrinsic Procedures 6.158 `NEAREST' -- Nearest representable number =============================================== _Description_: `NEAREST(X, S)' returns the processor-representable number nearest to `X' in the direction indicated by the sign of `S'. _Standard_: F95 and later _Class_: Elemental function _Syntax_: `RESULT = NEAREST(X, S)' _Arguments_: X Shall be of type `REAL'. S (Optional) shall be of type `REAL' and not equal to zero. _Return value_: The return value is of the same type as `X'. If `S' is positive, `NEAREST' returns the processor-representable number greater than `X' and nearest to it. If `S' is negative, `NEAREST' returns the processor-representable number smaller than `X' and nearest to it. _Example_: program test_nearest real :: x, y x = nearest(42.0, 1.0) y = nearest(42.0, -1.0) write (*,"(3(G20.15))") x, y, x - y end program test_nearest  File: gfortran.info, Node: NEW_LINE, Next: NINT, Prev: NEAREST, Up: Intrinsic Procedures 6.159 `NEW_LINE' -- New line character ====================================== _Description_: `NEW_LINE(C)' returns the new-line character. _Standard_: F2003 and later _Class_: Inquiry function _Syntax_: `RESULT = NEW_LINE(C)' _Arguments_: C The argument shall be a scalar or array of the type `CHARACTER'. _Return value_: Returns a CHARACTER scalar of length one with the new-line character of the same kind as parameter C. _Example_: program newline implicit none write(*,'(A)') 'This is record 1.'//NEW_LINE('A')//'This is record 2.' end program newline  File: gfortran.info, Node: NINT, Next: NOT, Prev: NEW_LINE, Up: Intrinsic Procedures 6.160 `NINT' -- Nearest whole number ==================================== _Description_: `NINT(X)' rounds its argument to the nearest whole number. _Standard_: F77 and later _Class_: Elemental function _Syntax_: `RESULT = NINT(X)' _Arguments_: X The type of the argument shall be `REAL'. _Return value_: Returns A with the fractional portion of its magnitude eliminated by rounding to the nearest whole number and with its sign preserved, converted to an `INTEGER' of the default kind. _Example_: program test_nint real(4) x4 real(8) x8 x4 = 1.234E0_4 x8 = 4.321_8 print *, nint(x4), idnint(x8) end program test_nint _Specific names_: Name Argument Standard `IDNINT(X)' `REAL(8)' F95 and later _See also_: *note CEILING::, *note FLOOR::  File: gfortran.info, Node: NOT, Next: NULL, Prev: NINT, Up: Intrinsic Procedures 6.161 `NOT' -- Logical negation =============================== _Description_: `NOT' returns the bitwise boolean inverse of I. _Standard_: F95 and later _Class_: Elemental function _Syntax_: `RESULT = NOT(I)' _Arguments_: I The type shall be `INTEGER(*)'. _Return value_: The return type is `INTEGER(*)', of the same kind as the argument. _See also_: *note IAND::, *note IEOR::, *note IOR::, *note IBITS::, *note IBSET::, *note IBCLR::  File: gfortran.info, Node: NULL, Next: OR, Prev: NOT, Up: Intrinsic Procedures 6.162 `NULL' -- Function that returns an disassociated pointer ============================================================== _Description_: Returns a disassociated pointer. If MOLD is present, a dissassociated pointer of the same type is returned, otherwise the type is determined by context. In Fortran 95, MOLD is optional. Please note that F2003 includes cases where it is required. _Standard_: F95 and later _Class_: Transformational function _Syntax_: `PTR => NULL([MOLD])' _Arguments_: MOLD (Optional) shall be a pointer of any association status and of any type. _Return value_: A disassociated pointer. _Example_: REAL, POINTER, DIMENSION(:) :: VEC => NULL () _See also_: *note ASSOCIATED::  File: gfortran.info, Node: OR, Next: PACK, Prev: NULL, Up: Intrinsic Procedures 6.163 `OR' -- Bitwise logical OR ================================ _Description_: Bitwise logical `OR'. This intrinsic routine is provided for backwards compatibility with GNU Fortran 77. For integer arguments, programmers should consider the use of the *note IOR:: intrinsic defined by the Fortran standard. _Standard_: GNU extension _Class_: Function _Syntax_: `RESULT = OR(X, Y)' _Arguments_: X The type shall be either `INTEGER(*)' or `LOGICAL'. Y The type shall be either `INTEGER(*)' or `LOGICAL'. _Return value_: The return type is either `INTEGER(*)' or `LOGICAL' after cross-promotion of the arguments. _Example_: PROGRAM test_or LOGICAL :: T = .TRUE., F = .FALSE. INTEGER :: a, b DATA a / Z'F' /, b / Z'3' / WRITE (*,*) OR(T, T), OR(T, F), OR(F, T), OR(F, F) WRITE (*,*) OR(a, b) END PROGRAM _See also_: F95 elemental function: *note IOR::  File: gfortran.info, Node: PACK, Next: PERROR, Prev: OR, Up: Intrinsic Procedures 6.164 `PACK' -- Pack an array into an array of rank one ======================================================= _Description_: Stores the elements of ARRAY in an array of rank one. The beginning of the resulting array is made up of elements whose MASK equals `TRUE'. Afterwards, positions are filled with elements taken from VECTOR. _Standard_: F95 and later _Class_: Transformational function _Syntax_: `RESULT = PACK(ARRAY, MASK[,VECTOR]' _Arguments_: ARRAY Shall be an array of any type. MASK Shall be an array of type `LOGICAL' and of the same size as ARRAY. Alternatively, it may be a `LOGICAL' scalar. VECTOR (Optional) shall be an array of the same type as ARRAY and of rank one. If present, the number of elements in VECTOR shall be equal to or greater than the number of true elements in MASK. If MASK is scalar, the number of elements in VECTOR shall be equal to or greater than the number of elements in ARRAY. _Return value_: The result is an array of rank one and the same type as that of ARRAY. If VECTOR is present, the result size is that of VECTOR, the number of `TRUE' values in MASK otherwise. _Example_: Gathering nonzero elements from an array: PROGRAM test_pack_1 INTEGER :: m(6) m = (/ 1, 0, 0, 0, 5, 0 /) WRITE(*, FMT="(6(I0, ' '))") pack(m, m /= 0) ! "1 5" END PROGRAM Gathering nonzero elements from an array and appending elements from VECTOR: PROGRAM test_pack_2 INTEGER :: m(4) m = (/ 1, 0, 0, 2 /) WRITE(*, FMT="(4(I0, ' '))") pack(m, m /= 0, (/ 0, 0, 3, 4 /)) ! "1 2 3 4" END PROGRAM _See also_: *note UNPACK::  File: gfortran.info, Node: PERROR, Next: PRECISION, Prev: PACK, Up: Intrinsic Procedures 6.165 `PERROR' -- Print system error message ============================================ _Description_: Prints (on the C `stderr' stream) a newline-terminated error message corresponding to the last system error. This is prefixed by STRING, a colon and a space. See `perror(3)'. _Standard_: GNU extension _Class_: Subroutine _Syntax_: `CALL PERROR(STRING)' _Arguments_: STRING A scalar of default `CHARACTER' type. _See also_: *note IERRNO::  File: gfortran.info, Node: PRECISION, Next: PRESENT, Prev: PERROR, Up: Intrinsic Procedures 6.166 `PRECISION' -- Decimal precision of a real kind ===================================================== _Description_: `PRECISION(X)' returns the decimal precision in the model of the type of `X'. _Standard_: F95 and later _Class_: Inquiry function _Syntax_: `RESULT = PRECISION(X)' _Arguments_: X Shall be of type `REAL' or `COMPLEX'. _Return value_: The return value is of type `INTEGER' and of the default integer kind. _Example_: program prec_and_range real(kind=4) :: x(2) complex(kind=8) :: y print *, precision(x), range(x) print *, precision(y), range(y) end program prec_and_range  File: gfortran.info, Node: PRESENT, Next: PRODUCT, Prev: PRECISION, Up: Intrinsic Procedures 6.167 `PRESENT' -- Determine whether an optional dummy argument is specified ============================================================================ _Description_: Determines whether an optional dummy argument is present. _Standard_: F95 and later _Class_: Inquiry function _Syntax_: `RESULT = PRESENT(A)' _Arguments_: A May be of any type and may be a pointer, scalar or array value, or a dummy procedure. It shall be the name of an optional dummy argument accessible within the current subroutine or function. _Return value_: Returns either `TRUE' if the optional argument A is present, or `FALSE' otherwise. _Example_: PROGRAM test_present WRITE(*,*) f(), f(42) ! "F T" CONTAINS LOGICAL FUNCTION f(x) INTEGER, INTENT(IN), OPTIONAL :: x f = PRESENT(x) END FUNCTION END PROGRAM  File: gfortran.info, Node: PRODUCT, Next: RADIX, Prev: PRESENT, Up: Intrinsic Procedures 6.168 `PRODUCT' -- Product of array elements ============================================ _Description_: Multiplies the elements of ARRAY along dimension DIM if the corresponding element in MASK is `TRUE'. _Standard_: F95 and later _Class_: Transformational function _Syntax_: `RESULT = PRODUCT(ARRAY[, MASK])' `RESULT = PRODUCT(ARRAY, DIM[, MASK])' _Arguments_: ARRAY Shall be an array of type `INTEGER(*)', `REAL(*)' or `COMPLEX(*)'. DIM (Optional) shall be a scalar of type `INTEGER' with a value in the range from 1 to n, where n equals the rank of ARRAY. MASK (Optional) shall be of type `LOGICAL' and either be a scalar or an array of the same shape as ARRAY. _Return value_: The result is of the same type as ARRAY. If DIM is absent, a scalar with the product of all elements in ARRAY is returned. Otherwise, an array of rank n-1, where n equals the rank of ARRAY, and a shape similar to that of ARRAY with dimension DIM dropped is returned. _Example_: PROGRAM test_product INTEGER :: x(5) = (/ 1, 2, 3, 4 ,5 /) print *, PRODUCT(x) ! all elements, product = 120 print *, PRODUCT(x, MASK=MOD(x, 2)==1) ! odd elements, product = 15 END PROGRAM _See also_: *note SUM::  File: gfortran.info, Node: RADIX, Next: RANDOM_NUMBER, Prev: PRODUCT, Up: Intrinsic Procedures 6.169 `RADIX' -- Base of a model number ======================================= _Description_: `RADIX(X)' returns the base of the model representing the entity X. _Standard_: F95 and later _Class_: Inquiry function _Syntax_: `RESULT = RADIX(X)' _Arguments_: X Shall be of type `INTEGER' or `REAL' _Return value_: The return value is a scalar of type `INTEGER' and of the default integer kind. _Example_: program test_radix print *, "The radix for the default integer kind is", radix(0) print *, "The radix for the default real kind is", radix(0.0) end program test_radix  File: gfortran.info, Node: RAN, Next: REAL, Prev: RANGE, Up: Intrinsic Procedures 6.170 `RAN' -- Real pseudo-random number ======================================== _Description_: For compatibility with HP FORTRAN 77/iX, the `RAN' intrinsic is provided as an alias for `RAND'. See *note RAND:: for complete documentation. _Standard_: GNU extension _Class_: Function _See also_: *note RAND::, *note RANDOM_NUMBER::  File: gfortran.info, Node: RAND, Next: RANGE, Prev: RANDOM_SEED, Up: Intrinsic Procedures 6.171 `RAND' -- Real pseudo-random number ========================================= _Description_: `RAND(FLAG)' returns a pseudo-random number from a uniform distribution between 0 and 1. If FLAG is 0, the next number in the current sequence is returned; if FLAG is 1, the generator is restarted by `CALL SRAND(0)'; if FLAG has any other value, it is used as a new seed with `SRAND'. This intrinsic routine is provided for backwards compatibility with GNU Fortran 77. It implements a simple modulo generator as provided by `g77'. For new code, one should consider the use of *note RANDOM_NUMBER:: as it implements a superior algorithm. _Standard_: GNU extension _Class_: Function _Syntax_: `RESULT = RAND(FLAG)' _Arguments_: FLAG Shall be a scalar `INTEGER' of kind 4. _Return value_: The return value is of `REAL' type and the default kind. _Example_: program test_rand integer,parameter :: seed = 86456 call srand(seed) print *, rand(), rand(), rand(), rand() print *, rand(seed), rand(), rand(), rand() end program test_rand _See also_: *note SRAND::, *note RANDOM_NUMBER::  File: gfortran.info, Node: RANDOM_NUMBER, Next: RANDOM_SEED, Prev: RADIX, Up: Intrinsic Procedures 6.172 `RANDOM_NUMBER' -- Pseudo-random number ============================================= _Description_: Returns a single pseudorandom number or an array of pseudorandom numbers from the uniform distribution over the range 0 \leq x < 1. The runtime-library implements George Marsaglia's KISS (Keep It Simple Stupid) random number generator (RNG). This RNG combines: 1. The congruential generator x(n) = 69069 \cdot x(n-1) + 1327217885 with a period of 2^32, 2. A 3-shift shift-register generator with a period of 2^32 - 1, 3. Two 16-bit multiply-with-carry generators with a period of 597273182964842497 > 2^59. The overall period exceeds 2^123. Please note, this RNG is thread safe if used within OpenMP directives, i. e. its state will be consistent while called from multiple threads. However, the KISS generator does not create random numbers in parallel from multiple sources, but in sequence from a single source. If an OpenMP-enabled application heavily relies on random numbers, one should consider employing a dedicated parallel random number generator instead. _Standard_: F95 and later _Class_: Subroutine _Syntax_: `RANDOM_NUMBER(HARVEST)' _Arguments_: HARVEST Shall be a scalar or an array of type `REAL(*)'. _Example_: program test_random_number REAL :: r(5,5) CALL init_random_seed() ! see example of RANDOM_SEED CALL RANDOM_NUMBER(r) end program _See also_: *note RANDOM_SEED::  File: gfortran.info, Node: RANDOM_SEED, Next: RAND, Prev: RANDOM_NUMBER, Up: Intrinsic Procedures 6.173 `RANDOM_SEED' -- Initialize a pseudo-random number sequence ================================================================= _Description_: Restarts or queries the state of the pseudorandom number generator used by `RANDOM_NUMBER'. If `RANDOM_SEED' is called without arguments, it is initialized to a default state. The example below shows how to initialize the random seed based on the system's time. _Standard_: F95 and later _Class_: Subroutine _Syntax_: `CALL RANDOM_SEED(SIZE, PUT, GET)' _Arguments_: SIZE (Optional) Shall be a scalar and of type default `INTEGER', with `INTENT(OUT)'. It specifies the minimum size of the arrays used with the PUT and GET arguments. PUT (Optional) Shall be an array of type default `INTEGER' and rank one. It is `INTENT(IN)' and the size of the array must be larger than or equal to the number returned by the SIZE argument. GET (Optional) Shall be an array of type default `INTEGER' and rank one. It is `INTENT(OUT)' and the size of the array must be larger than or equal to the number returned by the SIZE argument. _Example_: SUBROUTINE init_random_seed() INTEGER :: i, n, clock INTEGER, DIMENSION(:), ALLOCATABLE :: seed CALL RANDOM_SEED(size = n) ALLOCATE(seed(n)) CALL SYSTEM_CLOCK(COUNT=clock) seed = clock + 37 * (/ (i - 1, i = 1, n) /) CALL RANDOM_SEED(PUT = seed) DEALLOCATE(seed) END SUBROUTINE _See also_: *note RANDOM_NUMBER::  File: gfortran.info, Node: RANGE, Next: RAN, Prev: RAND, Up: Intrinsic Procedures 6.174 `RANGE' -- Decimal exponent range of a real kind ====================================================== _Description_: `RANGE(X)' returns the decimal exponent range in the model of the type of `X'. _Standard_: F95 and later _Class_: Inquiry function _Syntax_: `RESULT = RANGE(X)' _Arguments_: X Shall be of type `REAL' or `COMPLEX'. _Return value_: The return value is of type `INTEGER' and of the default integer kind. _Example_: See `PRECISION' for an example.  File: gfortran.info, Node: REAL, Next: RENAME, Prev: RAN, Up: Intrinsic Procedures 6.175 `REAL' -- Convert to real type ==================================== _Description_: `REAL(X [, KIND])' converts its argument X to a real type. The `REALPART(X)' function is provided for compatibility with `g77', and its use is strongly discouraged. _Standard_: F77 and later _Class_: Elemental function _Syntax_: `RESULT = REAL(X [, KIND])' `RESULT = REALPART(Z)' _Arguments_: X Shall be `INTEGER(*)', `REAL(*)', or `COMPLEX(*)'. KIND (Optional) An `INTEGER(*)' initialization expression indicating the kind parameter of the result. _Return value_: These functions return a `REAL(*)' variable or array under the following rules: (A) `REAL(X)' is converted to a default real type if X is an integer or real variable. (B) `REAL(X)' is converted to a real type with the kind type parameter of X if X is a complex variable. (C) `REAL(X, KIND)' is converted to a real type with kind type parameter KIND if X is a complex, integer, or real variable. _Example_: program test_real complex :: x = (1.0, 2.0) print *, real(x), real(x,8), realpart(x) end program test_real _See also_: *note DBLE::, *note DFLOAT::, *note FLOAT::  File: gfortran.info, Node: RENAME, Next: REPEAT, Prev: REAL, Up: Intrinsic Procedures 6.176 `RENAME' -- Rename a file =============================== _Description_: Renames a file from file PATH1 to PATH2. A null character (`CHAR(0)') can be used to mark the end of the names in PATH1 and PATH2; otherwise, trailing blanks in the file names are ignored. If the STATUS argument is supplied, it contains 0 on success or a nonzero error code upon return; see `rename(2)'. This intrinsic is provided in both subroutine and function forms; however, only one form can be used in any given program unit. _Standard_: GNU extension _Class_: Subroutine, function _Syntax_: `CALL RENAME(PATH1, PATH2 [, STATUS])' `STATUS = RENAME(PATH1, PATH2)' _Arguments_: PATH1 Shall be of default `CHARACTER' type. PATH2 Shall be of default `CHARACTER' type. STATUS (Optional) Shall be of default `INTEGER' type. _See also_: *note LINK::  File: gfortran.info, Node: REPEAT, Next: RESHAPE, Prev: RENAME, Up: Intrinsic Procedures 6.177 `REPEAT' -- Repeated string concatenation =============================================== _Description_: Concatenates NCOPIES copies of a string. _Standard_: F95 and later _Class_: Transformational function _Syntax_: `RESULT = REPEAT(STRING, NCOPIES)' _Arguments_: STRING Shall be scalar and of type `CHARACTER(*)'. NCOPIES Shall be scalar and of type `INTEGER(*)'. _Return value_: A new scalar of type `CHARACTER' built up from NCOPIES copies of STRING. _Example_: program test_repeat write(*,*) repeat("x", 5) ! "xxxxx" end program  File: gfortran.info, Node: RESHAPE, Next: RRSPACING, Prev: REPEAT, Up: Intrinsic Procedures 6.178 `RESHAPE' -- Function to reshape an array =============================================== _Description_: Reshapes SOURCE to correspond to SHAPE. If necessary, the new array may be padded with elements from PAD or permuted as defined by ORDER. _Standard_: F95 and later _Class_: Transformational function _Syntax_: `RESULT = RESHAPE(SOURCE, SHAPE[, PAD, ORDER])' _Arguments_: SOURCE Shall be an array of any type. SHAPE Shall be of type `INTEGER' and an array of rank one. Its values must be positive or zero. PAD (Optional) shall be an array of the same type as SOURCE. ORDER (Optional) shall be of type `INTEGER' and an array of the same shape as SHAPE. Its values shall be a permutation of the numbers from 1 to n, where n is the size of SHAPE. If ORDER is absent, the natural ordering shall be assumed. _Return value_: The result is an array of shape SHAPE with the same type as SOURCE. _Example_: PROGRAM test_reshape INTEGER, DIMENSION(4) :: x WRITE(*,*) SHAPE(x) ! prints "4" WRITE(*,*) SHAPE(RESHAPE(x, (/2, 2/))) ! prints "2 2" END PROGRAM _See also_: *note SHAPE::  File: gfortran.info, Node: RRSPACING, Next: RSHIFT, Prev: RESHAPE, Up: Intrinsic Procedures 6.179 `RRSPACING' -- Reciprocal of the relative spacing ======================================================= _Description_: `RRSPACING(X)' returns the reciprocal of the relative spacing of model numbers near X. _Standard_: F95 and later _Class_: Elemental function _Syntax_: `RESULT = RRSPACING(X)' _Arguments_: X Shall be of type `REAL'. _Return value_: The return value is of the same type and kind as X. The value returned is equal to `ABS(FRACTION(X)) * FLOAT(RADIX(X))**DIGITS(X)'. _See also_: *note SPACING::  File: gfortran.info, Node: RSHIFT, Next: SCALE, Prev: RRSPACING, Up: Intrinsic Procedures 6.180 `RSHIFT' -- Right shift bits ================================== _Description_: `RSHIFT' returns a value corresponding to I with all of the bits shifted right by SHIFT places. If the absolute value of SHIFT is greater than `BIT_SIZE(I)', the value is undefined. Bits shifted out from the left end are lost; zeros are shifted in from the opposite end. This function has been superseded by the `ISHFT' intrinsic, which is standard in Fortran 95 and later. _Standard_: GNU extension _Class_: Elemental function _Syntax_: `RESULT = RSHIFT(I, SHIFT)' _Arguments_: I The type shall be `INTEGER(*)'. SHIFT The type shall be `INTEGER(*)'. _Return value_: The return value is of type `INTEGER(*)' and of the same kind as I. _See also_: *note ISHFT::, *note ISHFTC::, *note LSHIFT::  File: gfortran.info, Node: SCALE, Next: SCAN, Prev: RSHIFT, Up: Intrinsic Procedures 6.181 `SCALE' -- Scale a real value =================================== _Description_: `SCALE(X,I)' returns `X * RADIX(X)**I'. _Standard_: F95 and later _Class_: Elemental function _Syntax_: `RESULT = SCALE(X, I)' _Arguments_: X The type of the argument shall be a `REAL'. I The type of the argument shall be a `INTEGER'. _Return value_: The return value is of the same type and kind as X. Its value is `X * RADIX(X)**I'. _Example_: program test_scale real :: x = 178.1387e-4 integer :: i = 5 print *, scale(x,i), x*radix(x)**i end program test_scale  File: gfortran.info, Node: SCAN, Next: SECNDS, Prev: SCALE, Up: Intrinsic Procedures 6.182 `SCAN' -- Scan a string for the presence of a set of characters ===================================================================== _Description_: Scans a STRING for any of the characters in a SET of characters. If BACK is either absent or equals `FALSE', this function returns the position of the leftmost character of STRING that is in SET. If BACK equals `TRUE', the rightmost position is returned. If no character of SET is found in STRING, the result is zero. _Standard_: F95 and later _Class_: Elemental function _Syntax_: `RESULT = SCAN(STRING, SET[, BACK [, KIND]])' _Arguments_: STRING Shall be of type `CHARACTER(*)'. SET Shall be of type `CHARACTER(*)'. BACK (Optional) shall be of type `LOGICAL'. KIND (Optional) An `INTEGER' initialization expression indicating the kind parameter of the result. _Return value_: The return value is of type `INTEGER' and of kind KIND. If KIND is absent, the return value is of default integer kind. _Example_: PROGRAM test_scan WRITE(*,*) SCAN("FORTRAN", "AO") ! 2, found 'O' WRITE(*,*) SCAN("FORTRAN", "AO", .TRUE.) ! 6, found 'A' WRITE(*,*) SCAN("FORTRAN", "C++") ! 0, found none END PROGRAM _See also_: *note INDEX intrinsic::, *note VERIFY::  File: gfortran.info, Node: SECNDS, Next: SECOND, Prev: SCAN, Up: Intrinsic Procedures 6.183 `SECNDS' -- Time function =============================== _Description_: `SECNDS(X)' gets the time in seconds from the real-time system clock. X is a reference time, also in seconds. If this is zero, the time in seconds from midnight is returned. This function is non-standard and its use is discouraged. _Standard_: GNU extension _Class_: Function _Syntax_: `RESULT = SECNDS (X)' _Arguments_: T Shall be of type `REAL(4)'. X Shall be of type `REAL(4)'. _Return value_: None _Example_: program test_secnds integer :: i real(4) :: t1, t2 print *, secnds (0.0) ! seconds since midnight t1 = secnds (0.0) ! reference time do i = 1, 10000000 ! do something end do t2 = secnds (t1) ! elapsed time print *, "Something took ", t2, " seconds." end program test_secnds  File: gfortran.info, Node: SECOND, Next: SELECTED_INT_KIND, Prev: SECNDS, Up: Intrinsic Procedures 6.184 `SECOND' -- CPU time function =================================== _Description_: Returns a `REAL(4)' value representing the elapsed CPU time in seconds. This provides the same functionality as the standard `CPU_TIME' intrinsic, and is only included for backwards compatibility. This intrinsic is provided in both subroutine and function forms; however, only one form can be used in any given program unit. _Standard_: GNU extension _Class_: Subroutine, function _Syntax_: `CALL SECOND(TIME)' `TIME = SECOND()' _Arguments_: TIME Shall be of type `REAL(4)'. _Return value_: In either syntax, TIME is set to the process's current runtime in seconds. _See also_: *note CPU_TIME::  File: gfortran.info, Node: SELECTED_INT_KIND, Next: SELECTED_REAL_KIND, Prev: SECOND, Up: Intrinsic Procedures 6.185 `SELECTED_INT_KIND' -- Choose integer kind ================================================ _Description_: `SELECTED_INT_KIND(I)' return the kind value of the smallest integer type that can represent all values ranging from -10^I (exclusive) to 10^I (exclusive). If there is no integer kind that accommodates this range, `SELECTED_INT_KIND' returns -1. _Standard_: F95 and later _Class_: Transformational function _Syntax_: `RESULT = SELECTED_INT_KIND(I)' _Arguments_: I Shall be a scalar and of type `INTEGER'. _Example_: program large_integers integer,parameter :: k5 = selected_int_kind(5) integer,parameter :: k15 = selected_int_kind(15) integer(kind=k5) :: i5 integer(kind=k15) :: i15 print *, huge(i5), huge(i15) ! The following inequalities are always true print *, huge(i5) >= 10_k5**5-1 print *, huge(i15) >= 10_k15**15-1 end program large_integers  File: gfortran.info, Node: SELECTED_REAL_KIND, Next: SET_EXPONENT, Prev: SELECTED_INT_KIND, Up: Intrinsic Procedures 6.186 `SELECTED_REAL_KIND' -- Choose real kind ============================================== _Description_: `SELECTED_REAL_KIND(P,R)' return the kind value of a real data type with decimal precision greater of at least `P' digits and exponent range greater at least `R'. _Standard_: F95 and later _Class_: Transformational function _Syntax_: `RESULT = SELECTED_REAL_KIND(P, R)' _Arguments_: P (Optional) shall be a scalar and of type `INTEGER'. R (Optional) shall be a scalar and of type `INTEGER'. At least one argument shall be present. _Return value_: `SELECTED_REAL_KIND' returns the value of the kind type parameter of a real data type with decimal precision of at least `P' digits and a decimal exponent range of at least `R'. If more than one real data type meet the criteria, the kind of the data type with the smallest decimal precision is returned. If no real data type matches the criteria, the result is -1 if the processor does not support a real data type with a precision greater than or equal to `P' -2 if the processor does not support a real type with an exponent range greater than or equal to `R' -3 if neither is supported. _Example_: program real_kinds integer,parameter :: p6 = selected_real_kind(6) integer,parameter :: p10r100 = selected_real_kind(10,100) integer,parameter :: r400 = selected_real_kind(r=400) real(kind=p6) :: x real(kind=p10r100) :: y real(kind=r400) :: z print *, precision(x), range(x) print *, precision(y), range(y) print *, precision(z), range(z) end program real_kinds  File: gfortran.info, Node: SET_EXPONENT, Next: SHAPE, Prev: SELECTED_REAL_KIND, Up: Intrinsic Procedures 6.187 `SET_EXPONENT' -- Set the exponent of the model ===================================================== _Description_: `SET_EXPONENT(X, I)' returns the real number whose fractional part is that that of X and whose exponent part is I. _Standard_: F95 and later _Class_: Elemental function _Syntax_: `RESULT = SET_EXPONENT(X, I)' _Arguments_: X Shall be of type `REAL'. I Shall be of type `INTEGER'. _Return value_: The return value is of the same type and kind as X. The real number whose fractional part is that that of X and whose exponent part if I is returned; it is `FRACTION(X) * RADIX(X)**I'. _Example_: PROGRAM test_setexp REAL :: x = 178.1387e-4 INTEGER :: i = 17 PRINT *, SET_EXPONENT(x, i), FRACTION(x) * RADIX(x)**i END PROGRAM  File: gfortran.info, Node: SHAPE, Next: SIGN, Prev: SET_EXPONENT, Up: Intrinsic Procedures 6.188 `SHAPE' -- Determine the shape of an array ================================================ _Description_: Determines the shape of an array. _Standard_: F95 and later _Class_: Inquiry function _Syntax_: `RESULT = SHAPE(SOURCE)' _Arguments_: SOURCE Shall be an array or scalar of any type. If SOURCE is a pointer it must be associated and allocatable arrays must be allocated. _Return value_: An `INTEGER' array of rank one with as many elements as SOURCE has dimensions. The elements of the resulting array correspond to the extend of SOURCE along the respective dimensions. If SOURCE is a scalar, the result is the rank one array of size zero. _Example_: PROGRAM test_shape INTEGER, DIMENSION(-1:1, -1:2) :: A WRITE(*,*) SHAPE(A) ! (/ 3, 4 /) WRITE(*,*) SIZE(SHAPE(42)) ! (/ /) END PROGRAM _See also_: *note RESHAPE::, *note SIZE::  File: gfortran.info, Node: SIGN, Next: SIGNAL, Prev: SHAPE, Up: Intrinsic Procedures 6.189 `SIGN' -- Sign copying function ===================================== _Description_: `SIGN(A,B)' returns the value of A with the sign of B. _Standard_: F77 and later _Class_: Elemental function _Syntax_: `RESULT = SIGN(A, B)' _Arguments_: A Shall be of type `INTEGER' or `REAL' B Shall be of the same type and kind as A _Return value_: The kind of the return value is that of A and B. If B\ge 0 then the result is `ABS(A)', else it is `-ABS(A)'. _Example_: program test_sign print *, sign(-12,1) print *, sign(-12,0) print *, sign(-12,-1) print *, sign(-12.,1.) print *, sign(-12.,0.) print *, sign(-12.,-1.) end program test_sign _Specific names_: Name Arguments Return type Standard `ISIGN(A,P)' `INTEGER(4)' `INTEGER(4)' f95, gnu `DSIGN(A,P)' `REAL(8)' `REAL(8)' f95, gnu  File: gfortran.info, Node: SIGNAL, Next: SIN, Prev: SIGN, Up: Intrinsic Procedures 6.190 `SIGNAL' -- Signal handling subroutine (or function) ========================================================== _Description_: `SIGNAL(NUMBER, HANDLER [, STATUS])' causes external subroutine HANDLER to be executed with a single integer argument when signal NUMBER occurs. If HANDLER is an integer, it can be used to turn off handling of signal NUMBER or revert to its default action. See `signal(2)'. If `SIGNAL' is called as a subroutine and the STATUS argument is supplied, it is set to the value returned by `signal(2)'. _Standard_: GNU extension _Class_: Subroutine, function _Syntax_: `CALL SIGNAL(NUMBER, HANDLER [, STATUS])' `STATUS = SIGNAL(NUMBER, HANDLER)' _Arguments_: NUMBER Shall be a scalar integer, with `INTENT(IN)' HANDLER Signal handler (`INTEGER FUNCTION' or `SUBROUTINE') or dummy/global `INTEGER' scalar. `INTEGER'. It is `INTENT(IN)'. STATUS (Optional) STATUS shall be a scalar integer. It has `INTENT(OUT)'. _Return value_: The `SIGNAL' function returns the value returned by `signal(2)'. _Example_: program test_signal intrinsic signal external handler_print call signal (12, handler_print) call signal (10, 1) call sleep (30) end program test_signal  File: gfortran.info, Node: SIN, Next: SINH, Prev: SIGNAL, Up: Intrinsic Procedures 6.191 `SIN' -- Sine function ============================ _Description_: `SIN(X)' computes the sine of X. _Standard_: F77 and later _Class_: Elemental function _Syntax_: `RESULT = SIN(X)' _Arguments_: X The type shall be `REAL(*)' or `COMPLEX(*)'. _Return value_: The return value has same type and kind as X. _Example_: program test_sin real :: x = 0.0 x = sin(x) end program test_sin _Specific names_: Name Argument Return type Standard `DSIN(X)' `REAL(8) X' `REAL(8)' f95, gnu `CSIN(X)' `COMPLEX(4) `COMPLEX(4)' f95, gnu X' `ZSIN(X)' `COMPLEX(8) `COMPLEX(8)' f95, gnu X' `CDSIN(X)' `COMPLEX(8) `COMPLEX(8)' f95, gnu X' _See also_: *note ASIN::  File: gfortran.info, Node: SINH, Next: SIZE, Prev: SIN, Up: Intrinsic Procedures 6.192 `SINH' -- Hyperbolic sine function ======================================== _Description_: `SINH(X)' computes the hyperbolic sine of X. _Standard_: F95 and later _Class_: Elemental function _Syntax_: `RESULT = SINH(X)' _Arguments_: X The type shall be `REAL(*)'. _Return value_: The return value is of type `REAL(*)'. _Example_: program test_sinh real(8) :: x = - 1.0_8 x = sinh(x) end program test_sinh _Specific names_: Name Argument Return type Standard `DSINH(X)' `REAL(8) X' `REAL(8)' F95 and later _See also_: *note ASINH::  File: gfortran.info, Node: SIZE, Next: SIZEOF, Prev: SINH, Up: Intrinsic Procedures 6.193 `SIZE' -- Determine the size of an array ============================================== _Description_: Determine the extent of ARRAY along a specified dimension DIM, or the total number of elements in ARRAY if DIM is absent. _Standard_: F95 and later _Class_: Inquiry function _Syntax_: `RESULT = SIZE(ARRAY[, DIM [, KIND]])' _Arguments_: ARRAY Shall be an array of any type. If ARRAY is a pointer it must be associated and allocatable arrays must be allocated. DIM (Optional) shall be a scalar of type `INTEGER' and its value shall be in the range from 1 to n, where n equals the rank of ARRAY. KIND (Optional) An `INTEGER' initialization expression indicating the kind parameter of the result. _Return value_: The return value is of type `INTEGER' and of kind KIND. If KIND is absent, the return value is of default integer kind. _Example_: PROGRAM test_size WRITE(*,*) SIZE((/ 1, 2 /)) ! 2 END PROGRAM _See also_: *note SHAPE::, *note RESHAPE::  File: gfortran.info, Node: SIZEOF, Next: SLEEP, Prev: SIZE, Up: Intrinsic Procedures 6.194 `SIZEOF' -- Size in bytes of an expression ================================================ _Description_: `SIZEOF(X)' calculates the number of bytes of storage the expression `X' occupies. _Standard_: GNU extension _Class_: Intrinsic function _Syntax_: `N = SIZEOF(X)' _Arguments_: X The argument shall be of any type, rank or shape. _Return value_: The return value is of type integer and of the system-dependent kind C_SIZE_T (from the ISO_C_BINDING module). Its value is the number of bytes occupied by the argument. If the argument has the `POINTER' attribute, the number of bytes of the storage area pointed to is returned. If the argument is of a derived type with `POINTER' or `ALLOCATABLE' components, the return value doesn't account for the sizes of the data pointed to by these components. _Example_: integer :: i real :: r, s(5) print *, (sizeof(s)/sizeof(r) == 5) end The example will print `.TRUE.' unless you are using a platform where default `REAL' variables are unusually padded.  File: gfortran.info, Node: SLEEP, Next: SNGL, Prev: SIZEOF, Up: Intrinsic Procedures 6.195 `SLEEP' -- Sleep for the specified number of seconds ========================================================== _Description_: Calling this subroutine causes the process to pause for SECONDS seconds. _Standard_: GNU extension _Class_: Subroutine _Syntax_: `CALL SLEEP(SECONDS)' _Arguments_: SECONDS The type shall be of default `INTEGER'. _Example_: program test_sleep call sleep(5) end  File: gfortran.info, Node: SNGL, Next: SPACING, Prev: SLEEP, Up: Intrinsic Procedures 6.196 `SNGL' -- Convert double precision real to default real ============================================================= _Description_: `SNGL(A)' converts the double precision real A to a default real value. This is an archaic form of `REAL' that is specific to one type for A. _Standard_: F77 and later _Class_: Elemental function _Syntax_: `RESULT = SNGL(A)' _Arguments_: A The type shall be a double precision `REAL'. _Return value_: The return value is of type default `REAL'. _See also_: *note DBLE::  File: gfortran.info, Node: SPACING, Next: SPREAD, Prev: SNGL, Up: Intrinsic Procedures 6.197 `SPACING' -- Smallest distance between two numbers of a given type ======================================================================== _Description_: Determines the distance between the argument X and the nearest adjacent number of the same type. _Standard_: F95 and later _Class_: Elemental function _Syntax_: `RESULT = SPACING(X)' _Arguments_: X Shall be of type `REAL(*)'. _Return value_: The result is of the same type as the input argument X. _Example_: PROGRAM test_spacing INTEGER, PARAMETER :: SGL = SELECTED_REAL_KIND(p=6, r=37) INTEGER, PARAMETER :: DBL = SELECTED_REAL_KIND(p=13, r=200) WRITE(*,*) spacing(1.0_SGL) ! "1.1920929E-07" on i686 WRITE(*,*) spacing(1.0_DBL) ! "2.220446049250313E-016" on i686 END PROGRAM _See also_: *note RRSPACING::  File: gfortran.info, Node: SPREAD, Next: SQRT, Prev: SPACING, Up: Intrinsic Procedures 6.198 `SPREAD' -- Add a dimension to an array ============================================= _Description_: Replicates a SOURCE array NCOPIES times along a specified dimension DIM. _Standard_: F95 and later _Class_: Transformational function _Syntax_: `RESULT = SPREAD(SOURCE, DIM, NCOPIES)' _Arguments_: SOURCE Shall be a scalar or an array of any type and a rank less than seven. DIM Shall be a scalar of type `INTEGER' with a value in the range from 1 to n+1, where n equals the rank of SOURCE. NCOPIES Shall be a scalar of type `INTEGER'. _Return value_: The result is an array of the same type as SOURCE and has rank n+1 where n equals the rank of SOURCE. _Example_: PROGRAM test_spread INTEGER :: a = 1, b(2) = (/ 1, 2 /) WRITE(*,*) SPREAD(A, 1, 2) ! "1 1" WRITE(*,*) SPREAD(B, 1, 2) ! "1 1 2 2" END PROGRAM _See also_: *note UNPACK::  File: gfortran.info, Node: SQRT, Next: SRAND, Prev: SPREAD, Up: Intrinsic Procedures 6.199 `SQRT' -- Square-root function ==================================== _Description_: `SQRT(X)' computes the square root of X. _Standard_: F77 and later _Class_: Elemental function _Syntax_: `RESULT = SQRT(X)' _Arguments_: X The type shall be `REAL(*)' or `COMPLEX(*)'. _Return value_: The return value is of type `REAL(*)' or `COMPLEX(*)'. The kind type parameter is the same as X. _Example_: program test_sqrt real(8) :: x = 2.0_8 complex :: z = (1.0, 2.0) x = sqrt(x) z = sqrt(z) end program test_sqrt _Specific names_: Name Argument Return type Standard `DSQRT(X)' `REAL(8) X' `REAL(8)' F95 and later `CSQRT(X)' `COMPLEX(4) `COMPLEX(4)' F95 and later X' `ZSQRT(X)' `COMPLEX(8) `COMPLEX(8)' GNU extension X' `CDSQRT(X)' `COMPLEX(8) `COMPLEX(8)' GNU extension X'  File: gfortran.info, Node: SRAND, Next: STAT, Prev: SQRT, Up: Intrinsic Procedures 6.200 `SRAND' -- Reinitialize the random number generator ========================================================= _Description_: `SRAND' reinitializes the pseudo-random number generator called by `RAND' and `IRAND'. The new seed used by the generator is specified by the required argument SEED. _Standard_: GNU extension _Class_: Subroutine _Syntax_: `CALL SRAND(SEED)' _Arguments_: SEED Shall be a scalar `INTEGER(kind=4)'. _Return value_: Does not return. _Example_: See `RAND' and `IRAND' for examples. _Notes_: The Fortran 2003 standard specifies the intrinsic `RANDOM_SEED' to initialize the pseudo-random numbers generator and `RANDOM_NUMBER' to generate pseudo-random numbers. Please note that in GNU Fortran, these two sets of intrinsics (`RAND', `IRAND' and `SRAND' on the one hand, `RANDOM_NUMBER' and `RANDOM_SEED' on the other hand) access two independent pseudo-random number generators. _See also_: *note RAND::, *note RANDOM_SEED::, *note RANDOM_NUMBER::  File: gfortran.info, Node: STAT, Next: SUM, Prev: SRAND, Up: Intrinsic Procedures 6.201 `STAT' -- Get file status =============================== _Description_: This function returns information about a file. No permissions are required on the file itself, but execute (search) permission is required on all of the directories in path that lead to the file. The elements that are obtained and stored in the array `BUFF': `buff(1)' Device ID `buff(2)' Inode number `buff(3)' File mode `buff(4)' Number of links `buff(5)' Owner's uid `buff(6)' Owner's gid `buff(7)' ID of device containing directory entry for file (0 if not available) `buff(8)' File size (bytes) `buff(9)' Last access time `buff(10)' Last modification time `buff(11)' Last file status change time `buff(12)' Preferred I/O block size (-1 if not available) `buff(13)' Number of blocks allocated (-1 if not available) Not all these elements are relevant on all systems. If an element is not relevant, it is returned as 0. This intrinsic is provided in both subroutine and function forms; however, only one form can be used in any given program unit. _Standard_: GNU extension _Class_: Subroutine, function _Syntax_: `CALL STAT(FILE,BUFF[,STATUS])' _Arguments_: FILE The type shall be `CHARACTER(*)', a valid path within the file system. BUFF The type shall be `INTEGER(4), DIMENSION(13)'. STATUS (Optional) status flag of type `INTEGER(4)'. Returns 0 on success and a system specific error code otherwise. _Example_: PROGRAM test_stat INTEGER, DIMENSION(13) :: buff INTEGER :: status CALL STAT("/etc/passwd", buff, status) IF (status == 0) THEN WRITE (*, FMT="('Device ID:', T30, I19)") buff(1) WRITE (*, FMT="('Inode number:', T30, I19)") buff(2) WRITE (*, FMT="('File mode (octal):', T30, O19)") buff(3) WRITE (*, FMT="('Number of links:', T30, I19)") buff(4) WRITE (*, FMT="('Owner''s uid:', T30, I19)") buff(5) WRITE (*, FMT="('Owner''s gid:', T30, I19)") buff(6) WRITE (*, FMT="('Device where located:', T30, I19)") buff(7) WRITE (*, FMT="('File size:', T30, I19)") buff(8) WRITE (*, FMT="('Last access time:', T30, A19)") CTIME(buff(9)) WRITE (*, FMT="('Last modification time', T30, A19)") CTIME(buff(10)) WRITE (*, FMT="('Last status change time:', T30, A19)") CTIME(buff(11)) WRITE (*, FMT="('Preferred block size:', T30, I19)") buff(12) WRITE (*, FMT="('No. of blocks allocated:', T30, I19)") buff(13) END IF END PROGRAM _See also_: To stat an open file: *note FSTAT::, to stat a link: *note LSTAT::  File: gfortran.info, Node: SUM, Next: SYMLNK, Prev: STAT, Up: Intrinsic Procedures 6.202 `SUM' -- Sum of array elements ==================================== _Description_: Adds the elements of ARRAY along dimension DIM if the corresponding element in MASK is `TRUE'. _Standard_: F95 and later _Class_: Transformational function _Syntax_: `RESULT = SUM(ARRAY[, MASK])' `RESULT = SUM(ARRAY, DIM[, MASK])' _Arguments_: ARRAY Shall be an array of type `INTEGER(*)', `REAL(*)' or `COMPLEX(*)'. DIM (Optional) shall be a scalar of type `INTEGER' with a value in the range from 1 to n, where n equals the rank of ARRAY. MASK (Optional) shall be of type `LOGICAL' and either be a scalar or an array of the same shape as ARRAY. _Return value_: The result is of the same type as ARRAY. If DIM is absent, a scalar with the sum of all elements in ARRAY is returned. Otherwise, an array of rank n-1, where n equals the rank of ARRAY,and a shape similar to that of ARRAY with dimension DIM dropped is returned. _Example_: PROGRAM test_sum INTEGER :: x(5) = (/ 1, 2, 3, 4 ,5 /) print *, SUM(x) ! all elements, sum = 15 print *, SUM(x, MASK=MOD(x, 2)==1) ! odd elements, sum = 9 END PROGRAM _See also_: *note PRODUCT::  File: gfortran.info, Node: SYMLNK, Next: SYSTEM, Prev: SUM, Up: Intrinsic Procedures 6.203 `SYMLNK' -- Create a symbolic link ======================================== _Description_: Makes a symbolic link from file PATH1 to PATH2. A null character (`CHAR(0)') can be used to mark the end of the names in PATH1 and PATH2; otherwise, trailing blanks in the file names are ignored. If the STATUS argument is supplied, it contains 0 on success or a nonzero error code upon return; see `symlink(2)'. If the system does not supply `symlink(2)', `ENOSYS' is returned. This intrinsic is provided in both subroutine and function forms; however, only one form can be used in any given program unit. _Standard_: GNU extension _Class_: Subroutine, function _Syntax_: `CALL SYMLNK(PATH1, PATH2 [, STATUS])' `STATUS = SYMLNK(PATH1, PATH2)' _Arguments_: PATH1 Shall be of default `CHARACTER' type. PATH2 Shall be of default `CHARACTER' type. STATUS (Optional) Shall be of default `INTEGER' type. _See also_: *note LINK::, *note UNLINK::  File: gfortran.info, Node: SYSTEM, Next: SYSTEM_CLOCK, Prev: SYMLNK, Up: Intrinsic Procedures 6.204 `SYSTEM' -- Execute a shell command ========================================= _Description_: Passes the command COMMAND to a shell (see `system(3)'). If argument STATUS is present, it contains the value returned by `system(3)', which is presumably 0 if the shell command succeeded. Note that which shell is used to invoke the command is system-dependent and environment-dependent. This intrinsic is provided in both subroutine and function forms; however, only one form can be used in any given program unit. _Standard_: GNU extension _Class_: Subroutine, function _Syntax_: `CALL SYSTEM(COMMAND [, STATUS])' `STATUS = SYSTEM(COMMAND)' _Arguments_: COMMAND Shall be of default `CHARACTER' type. STATUS (Optional) Shall be of default `INTEGER' type. _See also_:  File: gfortran.info, Node: SYSTEM_CLOCK, Next: TAN, Prev: SYSTEM, Up: Intrinsic Procedures 6.205 `SYSTEM_CLOCK' -- Time function ===================================== _Description_: Determines the COUNT of milliseconds of wall clock time since the Epoch (00:00:00 UTC, January 1, 1970) modulo COUNT_MAX, COUNT_RATE determines the number of clock ticks per second. COUNT_RATE and COUNT_MAX are constant and specific to `gfortran'. If there is no clock, COUNT is set to `-HUGE(COUNT)', and COUNT_RATE and COUNT_MAX are set to zero _Standard_: F95 and later _Class_: Subroutine _Syntax_: `CALL SYSTEM_CLOCK([COUNT, COUNT_RATE, COUNT_MAX])' _Arguments_: _Arguments_: COUNT (Optional) shall be a scalar of type default `INTEGER' with `INTENT(OUT)'. COUNT_RATE (Optional) shall be a scalar of type default `INTEGER' with `INTENT(OUT)'. COUNT_MAX (Optional) shall be a scalar of type default `INTEGER' with `INTENT(OUT)'. _Example_: PROGRAM test_system_clock INTEGER :: count, count_rate, count_max CALL SYSTEM_CLOCK(count, count_rate, count_max) WRITE(*,*) count, count_rate, count_max END PROGRAM _See also_: *note DATE_AND_TIME::, *note CPU_TIME::  File: gfortran.info, Node: TAN, Next: TANH, Prev: SYSTEM_CLOCK, Up: Intrinsic Procedures 6.206 `TAN' -- Tangent function =============================== _Description_: `TAN(X)' computes the tangent of X. _Standard_: F77 and later _Class_: Elemental function _Syntax_: `RESULT = TAN(X)' _Arguments_: X The type shall be `REAL(*)'. _Return value_: The return value is of type `REAL(*)'. The kind type parameter is the same as X. _Example_: program test_tan real(8) :: x = 0.165_8 x = tan(x) end program test_tan _Specific names_: Name Argument Return type Standard `DTAN(X)' `REAL(8) X' `REAL(8)' F95 and later _See also_: *note ATAN::  File: gfortran.info, Node: TANH, Next: TIME, Prev: TAN, Up: Intrinsic Procedures 6.207 `TANH' -- Hyperbolic tangent function =========================================== _Description_: `TANH(X)' computes the hyperbolic tangent of X. _Standard_: F77 and later _Class_: Elemental function _Syntax_: `X = TANH(X)' _Arguments_: X The type shall be `REAL(*)'. _Return value_: The return value is of type `REAL(*)' and lies in the range - 1 \leq tanh(x) \leq 1 . _Example_: program test_tanh real(8) :: x = 2.1_8 x = tanh(x) end program test_tanh _Specific names_: Name Argument Return type Standard `DTANH(X)' `REAL(8) X' `REAL(8)' F95 and later _See also_: *note ATANH::  File: gfortran.info, Node: TIME, Next: TIME8, Prev: TANH, Up: Intrinsic Procedures 6.208 `TIME' -- Time function ============================= _Description_: Returns the current time encoded as an integer (in the manner of the UNIX function `time(3)'). This value is suitable for passing to `CTIME()', `GMTIME()', and `LTIME()'. This intrinsic is not fully portable, such as to systems with 32-bit `INTEGER' types but supporting times wider than 32 bits. Therefore, the values returned by this intrinsic might be, or become, negative, or numerically less than previous values, during a single run of the compiled program. See *note TIME8::, for information on a similar intrinsic that might be portable to more GNU Fortran implementations, though to fewer Fortran compilers. _Standard_: GNU extension _Class_: Function _Syntax_: `RESULT = TIME()' _Return value_: The return value is a scalar of type `INTEGER(4)'. _See also_: *note CTIME::, *note GMTIME::, *note LTIME::, *note MCLOCK::, *note TIME8::  File: gfortran.info, Node: TIME8, Next: TINY, Prev: TIME, Up: Intrinsic Procedures 6.209 `TIME8' -- Time function (64-bit) ======================================= _Description_: Returns the current time encoded as an integer (in the manner of the UNIX function `time(3)'). This value is suitable for passing to `CTIME()', `GMTIME()', and `LTIME()'. _Warning:_ this intrinsic does not increase the range of the timing values over that returned by `time(3)'. On a system with a 32-bit `time(3)', `TIME8()' will return a 32-bit value, even though it is converted to a 64-bit `INTEGER(8)' value. That means overflows of the 32-bit value can still occur. Therefore, the values returned by this intrinsic might be or become negative or numerically less than previous values during a single run of the compiled program. _Standard_: GNU extension _Class_: Function _Syntax_: `RESULT = TIME8()' _Return value_: The return value is a scalar of type `INTEGER(8)'. _See also_: *note CTIME::, *note GMTIME::, *note LTIME::, *note MCLOCK8::, *note TIME::  File: gfortran.info, Node: TINY, Next: TRANSFER, Prev: TIME8, Up: Intrinsic Procedures 6.210 `TINY' -- Smallest positive number of a real kind ======================================================= _Description_: `TINY(X)' returns the smallest positive (non zero) number in the model of the type of `X'. _Standard_: F95 and later _Class_: Inquiry function _Syntax_: `RESULT = TINY(X)' _Arguments_: X Shall be of type `REAL'. _Return value_: The return value is of the same type and kind as X _Example_: See `HUGE' for an example.  File: gfortran.info, Node: TRANSFER, Next: TRANSPOSE, Prev: TINY, Up: Intrinsic Procedures 6.211 `TRANSFER' -- Transfer bit patterns ========================================= _Description_: Interprets the bitwise representation of SOURCE in memory as if it is the representation of a variable or array of the same type and type parameters as MOLD. This is approximately equivalent to the C concept of _casting_ one type to another. _Standard_: F95 and later _Class_: Transformational function _Syntax_: `RESULT = TRANSFER(SOURCE, MOLD[, SIZE])' _Arguments_: SOURCE Shall be a scalar or an array of any type. MOLD Shall be a scalar or an array of any type. SIZE (Optional) shall be a scalar of type `INTEGER'. _Return value_: The result has the same type as MOLD, with the bit level representation of SOURCE. If SIZE is present, the result is a one-dimensional array of length SIZE. If SIZE is absent but MOLD is an array (of any size or shape), the result is a one- dimensional array of the minimum length needed to contain the entirety of the bitwise representation of SOURCE. If SIZE is absent and MOLD is a scalar, the result is a scalar. If the bitwise representation of the result is longer than that of SOURCE, then the leading bits of the result correspond to those of SOURCE and any trailing bits are filled arbitrarily. When the resulting bit representation does not correspond to a valid representation of a variable of the same type as MOLD, the results are undefined, and subsequent operations on the result cannot be guaranteed to produce sensible behavior. For example, it is possible to create `LOGICAL' variables for which `VAR' and `.NOT.VAR' both appear to be true. _Example_: PROGRAM test_transfer integer :: x = 2143289344 print *, transfer(x, 1.0) ! prints "NaN" on i686 END PROGRAM  File: gfortran.info, Node: TRANSPOSE, Next: TRIM, Prev: TRANSFER, Up: Intrinsic Procedures 6.212 `TRANSPOSE' -- Transpose an array of rank two =================================================== _Description_: Transpose an array of rank two. Element (i, j) of the result has the value `MATRIX(j, i)', for all i, j. _Standard_: F95 and later _Class_: Transformational function _Syntax_: `RESULT = TRANSPOSE(MATRIX)' _Arguments_: MATRIX Shall be an array of any type and have a rank of two. _Return value_: The result has the the same type as MATRIX, and has shape `(/ m, n /)' if MATRIX has shape `(/ n, m /)'.  File: gfortran.info, Node: TRIM, Next: TTYNAM, Prev: TRANSPOSE, Up: Intrinsic Procedures 6.213 `TRIM' -- Remove trailing blank characters of a string ============================================================ _Description_: Removes trailing blank characters of a string. _Standard_: F95 and later _Class_: Transformational function _Syntax_: `RESULT = TRIM(STRING)' _Arguments_: STRING Shall be a scalar of type `CHARACTER(*)'. _Return value_: A scalar of type `CHARACTER(*)' which length is that of STRING less the number of trailing blanks. _Example_: PROGRAM test_trim CHARACTER(len=10), PARAMETER :: s = "GFORTRAN " WRITE(*,*) LEN(s), LEN(TRIM(s)) ! "10 8", with/without trailing blanks END PROGRAM _See also_: *note ADJUSTL::, *note ADJUSTR::  File: gfortran.info, Node: TTYNAM, Next: UBOUND, Prev: TRIM, Up: Intrinsic Procedures 6.214 `TTYNAM' -- Get the name of a terminal device. ==================================================== _Description_: Get the name of a terminal device. For more information, see `ttyname(3)'. This intrinsic is provided in both subroutine and function forms; however, only one form can be used in any given program unit. _Standard_: GNU extension _Class_: Subroutine, function _Syntax_: `CALL TTYNAM(UNIT, NAME)' `NAME = TTYNAM(UNIT)' _Arguments_: UNIT Shall be a scalar `INTEGER(*)'. NAME Shall be of type `CHARACTER(*)'. _Example_: PROGRAM test_ttynam INTEGER :: unit DO unit = 1, 10 IF (isatty(unit=unit)) write(*,*) ttynam(unit) END DO END PROGRAM _See also_: *note ISATTY::  File: gfortran.info, Node: UBOUND, Next: UMASK, Prev: TTYNAM, Up: Intrinsic Procedures 6.215 `UBOUND' -- Upper dimension bounds of an array ==================================================== _Description_: Returns the upper bounds of an array, or a single upper bound along the DIM dimension. _Standard_: F95 and later _Class_: Inquiry function _Syntax_: `RESULT = UBOUND(ARRAY [, DIM [, KIND]])' _Arguments_: ARRAY Shall be an array, of any type. DIM (Optional) Shall be a scalar `INTEGER(*)'. KIND (Optional) An `INTEGER' initialization expression indicating the kind parameter of the result. _Return value_: The return value is of type `INTEGER' and of kind KIND. If KIND is absent, the return value is of default integer kind. If DIM is absent, the result is an array of the upper bounds of ARRAY. If DIM is present, the result is a scalar corresponding to the upper bound of the array along that dimension. If ARRAY is an expression rather than a whole array or array structure component, or if it has a zero extent along the relevant dimension, the upper bound is taken to be the number of elements along the relevant dimension. _See also_: *note LBOUND::  File: gfortran.info, Node: UMASK, Next: UNLINK, Prev: UBOUND, Up: Intrinsic Procedures 6.216 `UMASK' -- Set the file creation mask =========================================== _Description_: Sets the file creation mask to MASK and returns the old value in argument OLD if it is supplied. See `umask(2)'. _Standard_: GNU extension _Class_: Subroutine _Syntax_: `CALL UMASK(MASK [, OLD])' _Arguments_: MASK Shall be a scalar of type `INTEGER(*)'. MASK (Optional) Shall be a scalar of type `INTEGER(*)'.  File: gfortran.info, Node: UNLINK, Next: UNPACK, Prev: UMASK, Up: Intrinsic Procedures 6.217 `UNLINK' -- Remove a file from the file system ==================================================== _Description_: Unlinks the file PATH. A null character (`CHAR(0)') can be used to mark the end of the name in PATH; otherwise, trailing blanks in the file name are ignored. If the STATUS argument is supplied, it contains 0 on success or a nonzero error code upon return; see `unlink(2)'. This intrinsic is provided in both subroutine and function forms; however, only one form can be used in any given program unit. _Standard_: GNU extension _Class_: Subroutine, function _Syntax_: `CALL UNLINK(PATH [, STATUS])' `STATUS = UNLINK(PATH)' _Arguments_: PATH Shall be of default `CHARACTER' type. STATUS (Optional) Shall be of default `INTEGER' type. _See also_: *note LINK::, *note SYMLNK::  File: gfortran.info, Node: UNPACK, Next: VERIFY, Prev: UNLINK, Up: Intrinsic Procedures 6.218 `UNPACK' -- Unpack an array of rank one into an array =========================================================== _Description_: Store the elements of VECTOR in an array of higher rank. _Standard_: F95 and later _Class_: Transformational function _Syntax_: `RESULT = UNPACK(VECTOR, MASK, FIELD)' _Arguments_: VECTOR Shall be an array of any type and rank one. It shall have at least as many elements as MASK has `TRUE' values. MASK Shall be an array of type `LOGICAL'. FIELD Shall be of the sam type as VECTOR and have the same shape as MASK. _Return value_: The resulting array corresponds to FIELD with `TRUE' elements of MASK replaced by values from VECTOR in array element order. _Example_: PROGRAM test_unpack integer :: vector(2) = (/1,1/) logical :: mask(4) = (/ .TRUE., .FALSE., .FALSE., .TRUE. /) integer :: field(2,2) = 0, unity(2,2) ! result: unity matrix unity = unpack(vector, reshape(mask, (/2,2/)), field) END PROGRAM _See also_: *note PACK::, *note SPREAD::  File: gfortran.info, Node: VERIFY, Next: XOR, Prev: UNPACK, Up: Intrinsic Procedures 6.219 `VERIFY' -- Scan a string for the absence of a set of characters ====================================================================== _Description_: Verifies that all the characters in a SET are present in a STRING. If BACK is either absent or equals `FALSE', this function returns the position of the leftmost character of STRING that is not in SET. If BACK equals `TRUE', the rightmost position is returned. If all characters of SET are found in STRING, the result is zero. _Standard_: F95 and later _Class_: Elemental function _Syntax_: `RESULT = VERIFY(STRING, SET[, BACK [, KIND]])' _Arguments_: STRING Shall be of type `CHARACTER(*)'. SET Shall be of type `CHARACTER(*)'. BACK (Optional) shall be of type `LOGICAL'. KIND (Optional) An `INTEGER' initialization expression indicating the kind parameter of the result. _Return value_: The return value is of type `INTEGER' and of kind KIND. If KIND is absent, the return value is of default integer kind. _Example_: PROGRAM test_verify WRITE(*,*) VERIFY("FORTRAN", "AO") ! 1, found 'F' WRITE(*,*) VERIFY("FORTRAN", "FOO") ! 3, found 'R' WRITE(*,*) VERIFY("FORTRAN", "C++") ! 1, found 'F' WRITE(*,*) VERIFY("FORTRAN", "C++", .TRUE.) ! 7, found 'N' WRITE(*,*) VERIFY("FORTRAN", "FORTRAN") ! 0' found none END PROGRAM _See also_: *note SCAN::, *note INDEX intrinsic::  File: gfortran.info, Node: XOR, Prev: VERIFY, Up: Intrinsic Procedures 6.220 `XOR' -- Bitwise logical exclusive OR =========================================== _Description_: Bitwise logical exclusive or. This intrinsic routine is provided for backwards compatibility with GNU Fortran 77. For integer arguments, programmers should consider the use of the *note IEOR:: intrinsic defined by the Fortran standard. _Standard_: GNU extension _Class_: Function _Syntax_: `RESULT = XOR(X, Y)' _Arguments_: X The type shall be either `INTEGER(*)' or `LOGICAL'. Y The type shall be either `INTEGER(*)' or `LOGICAL'. _Return value_: The return type is either `INTEGER(*)' or `LOGICAL' after cross-promotion of the arguments. _Example_: PROGRAM test_xor LOGICAL :: T = .TRUE., F = .FALSE. INTEGER :: a, b DATA a / Z'F' /, b / Z'3' / WRITE (*,*) XOR(T, T), XOR(T, F), XOR(F, T), XOR(F, F) WRITE (*,*) XOR(a, b) END PROGRAM _See also_: F95 elemental function: *note IEOR::  File: gfortran.info, Node: Intrinsic Modules, Next: Contributing, Prev: Intrinsic Procedures, Up: Top 7 Intrinsic Modules ******************* 7.1 `ISO_FORTRAN_ENV' ===================== _Standard_: Fortran 2003 The `ISO_FORTRAN_ENV' module provides the following scalar default-integer named constants: `CHARACTER_STORAGE_SIZE': Size in bits of the character storage unit. `ERROR_UNIT': Indentifies the preconnected unit used for error reporting. `FILE_STORAGE_SIZE': Size in bits of the file-storage unit. `INPUT_UNIT': Indentifies the preconnected unit indentified by the asterisk (`*') in `READ' statement. `IOSTAT_END': The value assigned to the variable passed to the IOSTAT= specifier of an input/output statement if an end-of-file condition occurred. `IOSTAT_EOR': The value assigned to the variable passed to the IOSTAT= specifier of an input/output statement if an end-of-record condition occurred. `NUMERIC_STORAGE_SIZE': The size in bits of the numeric storage unit. `OUTPUT_UNIT': Indentifies the preconnected unit indentified by the asterisk (`*') in `WRITE' statement. 7.2 `ISO_C_BINDING' =================== _Standard_: Fortran 2003 The following intrinsic procedures are provided by the module; their definition can be found in the section Intrinsic Procedures of this manual. `C_ASSOCIATED' `C_F_POINTER' `C_F_PROCPOINTER' `C_FUNLOC' `C_LOC' The `ISO_C_BINDING' module provides the following named constants of the type integer, which can be used as KIND type parameter. Note that GNU Fortran currently does not support the `C_INT_FAST...' KIND type parameters (marked by an asterix (`*') in the list below). The `C_INT_FAST...' parameters have therefore the value -2 and cannot be used as KIND type parameter of the `INTEGER' type. Fortran Named constant C type Type `INTEGER' `C_INT' `int' `INTEGER' `C_SHORT' `short int' `INTEGER' `C_LONG' `long int' `INTEGER' `C_LONG_LONG' `long long int' `INTEGER' `C_SIGNED_CHAR' `signed char'/`unsigned char' `INTEGER' `C_SIZE_T' `size_t' `INTEGER' `C_INT8_T' `int8_t' `INTEGER' `C_INT16_T' `int16_t' `INTEGER' `C_INT32_T' `int32_t' `INTEGER' `C_INT64_T' `int64_t' `INTEGER' `C_INT_LEAST8_T' `int_least8_t' `INTEGER' `C_INT_LEAST16_T' `int_least16_t' `INTEGER' `C_INT_LEAST32_T' `int_least32_t' `INTEGER' `C_INT_LEAST64_T' `int_least64_t' `INTEGER' `C_INT_FAST8_T'* `int_fast8_t' `INTEGER' `C_INT_FAST16_T'* `int_fast16_t' `INTEGER' `C_INT_FAST32_T'* `int_fast32_t' `INTEGER' `C_INT_FAST64_T'* `int_fast64_t' `INTEGER' `C_INTMAX_T' `intmax_t' `INTEGER' `C_INTPTR_T' `intptr_t' `REAL' `C_FLOAT' `float' `REAL' `C_DOUBLE' `double' `REAL' `C_LONG_DOUBLE' `long double' `COMPLEX' `C_FLOAT_COMPLEX' `float _Complex' `COMPLEX' `C_DOUBLE_COMPLEX' `double _Complex' `COMPLEX' `C_LONG_DOUBLE_COMPLEX' `long double _Complex' `LOGICAL' `C_BOOL' `_Bool' `CHARACTER' `C_CHAR' `char' Additionally, the following `(CHARACTER(KIND=C_CHAR)' are defined. Name C definition Value `C_NULL_CHAR' null character `'\0'' `C_ALERT' alert `'\a'' `C_BACKSPACE' backspace `'\b'' `C_FORM_FEED' form feed `'\f'' `C_NEW_LINE' new line `'\n'' `C_CARRIAGE_RETURN'carriage return `'\r'' `C_HORIZONTAL_TAB'horizontal tab `'\t'' `C_VERTICAL_TAB'vertical tab `'\v'' 7.3 OpenMP Modules `OMP_LIB' and `OMP_LIB_KINDS' ================================================ _Standard_: OpenMP Application Program Interface v2.5 The OpenMP Fortran runtime library routines are provided both in a form of two Fortran 90 modules, named `OMP_LIB' and `OMP_LIB_KINDS', and in a form of a Fortran `include' file named `omp_lib.h'. The procedures provided by `OMP_LIB' can be found in the *note Introduction: (libgomp)Top. manual, the named constants defined in the `OMP_LIB_KINDS' module are listed below. For details refer to the actual OpenMP Application Program Interface v2.5 (http://www.openmp.org/drupal/mp-documents/spec25.pdf). `OMP_LIB_KINDS' provides the following scalar default-integer named constants: `omp_integer_kind' `omp_logical_kind' `omp_lock_kind' `omp_nest_lock_kind'  File: gfortran.info, Node: Contributing, Next: Copying, Prev: Intrinsic Modules, Up: Top Contributing ************ Free software is only possible if people contribute to efforts to create it. We're always in need of more people helping out with ideas and comments, writing documentation and contributing code. If you want to contribute to GNU Fortran, have a look at the long lists of projects you can take on. Some of these projects are small, some of them are large; some are completely orthogonal to the rest of what is happening on GNU Fortran, but others are "mainstream" projects in need of enthusiastic hackers. All of these projects are important! We'll eventually get around to the things here, but they are also things doable by someone who is willing and able. * Menu: * Contributors:: * Projects:: * Proposed Extensions::  File: gfortran.info, Node: Contributors, Next: Projects, Up: Contributing Contributors to GNU Fortran =========================== Most of the parser was hand-crafted by _Andy Vaught_, who is also the initiator of the whole project. Thanks Andy! Most of the interface with GCC was written by _Paul Brook_. The following individuals have contributed code and/or ideas and significant help to the GNU Fortran project (in alphabetical order): - Janne Blomqvist - Steven Bosscher - Paul Brook - Tobias Burnus - Franc,ois-Xavier Coudert - Bud Davis - Jerry DeLisle - Erik Edelmann - Bernhard Fischer - Daniel Franke - Richard Guenther - Richard Henderson - Katherine Holcomb - Jakub Jelinek - Niels Kristian Bech Jensen - Steven Johnson - Steven G. Kargl - Thomas Koenig - Asher Langton - H. J. Lu - Toon Moene - Brooks Moses - Andrew Pinski - Tim Prince - Christopher D. Rickett - Richard Sandiford - Tobias Schlu"ter - Roger Sayle - Paul Thomas - Andy Vaught - Feng Wang - Janus Weil The following people have contributed bug reports, smaller or larger patches, and much needed feedback and encouragement for the GNU Fortran project: - Bill Clodius - Dominique d'Humie`res - Kate Hedstrom - Erik Schnetter Many other individuals have helped debug, test and improve the GNU Fortran compiler over the past few years, and we welcome you to do the same! If you already have done so, and you would like to see your name listed in the list above, please contact us.  File: gfortran.info, Node: Projects, Next: Proposed Extensions, Prev: Contributors, Up: Contributing Projects ======== _Help build the test suite_ Solicit more code for donation to the test suite: the more extensive the testsuite, the smaller the risk of breaking things in the future! We can keep code private on request. _Bug hunting/squishing_ Find bugs and write more test cases! Test cases are especially very welcome, because it allows us to concentrate on fixing bugs instead of isolating them. Going through the bugzilla database at `http://gcc.gnu.org/bugzilla/' to reduce testcases posted there and add more information (for example, for which version does the testcase work, for which versions does it fail?) is also very helpful.  File: gfortran.info, Node: Proposed Extensions, Prev: Projects, Up: Contributing Proposed Extensions =================== Here's a list of proposed extensions for the GNU Fortran compiler, in no particular order. Most of these are necessary to be fully compatible with existing Fortran compilers, but they are not part of the official J3 Fortran 95 standard. Compiler extensions: -------------------- * User-specified alignment rules for structures. * Flag to generate `Makefile' info. * Automatically extend single precision constants to double. * Compile code that conserves memory by dynamically allocating common and module storage either on stack or heap. * Compile flag to generate code for array conformance checking (suggest -CC). * User control of symbol names (underscores, etc). * Compile setting for maximum size of stack frame size before spilling parts to static or heap. * Flag to force local variables into static space. * Flag to force local variables onto stack. Environment Options ------------------- * Pluggable library modules for random numbers, linear algebra. LA should use BLAS calling conventions. * Environment variables controlling actions on arithmetic exceptions like overflow, underflow, precision loss--Generate NaN, abort, default. action. * Set precision for fp units that support it (i387). * Variable for setting fp rounding mode. * Variable to fill uninitialized variables with a user-defined bit pattern. * Environment variable controlling filename that is opened for that unit number. * Environment variable to clear/trash memory being freed. * Environment variable to control tracing of allocations and frees. * Environment variable to display allocated memory at normal program end. * Environment variable for filename for * IO-unit. * Environment variable for temporary file directory. * Environment variable forcing standard output to be line buffered (unix).  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For example, you may not impose a license fee, royalty, or other charge for exercise of rights granted under this License, and you may not initiate litigation (including a cross-claim or counterclaim in a lawsuit) alleging that any patent claim is infringed by making, using, selling, offering for sale, or importing the Program or any portion of it. 11. Patents. A "contributor" is a copyright holder who authorizes use under this License of the Program or a work on which the Program is based. The work thus licensed is called the contributor's "contributor version". A contributor's "essential patent claims" are all patent claims owned or controlled by the contributor, whether already acquired or hereafter acquired, that would be infringed by some manner, permitted by this License, of making, using, or selling its contributor version, but do not include claims that would be infringed only as a consequence of further modification of the contributor version. For purposes of this definition, "control" includes the right to grant patent sublicenses in a manner consistent with the requirements of this License. Each contributor grants you a non-exclusive, worldwide, royalty-free patent license under the contributor's essential patent claims, to make, use, sell, offer for sale, import and otherwise run, modify and propagate the contents of its contributor version. In the following three paragraphs, a "patent license" is any express agreement or commitment, however denominated, not to enforce a patent (such as an express permission to practice a patent or covenant not to sue for patent infringement). To "grant" such a patent license to a party means to make such an agreement or commitment not to enforce a patent against the party. If you convey a covered work, knowingly relying on a patent license, and the Corresponding Source of the work is not available for anyone to copy, free of charge and under the terms of this License, through a publicly available network server or other readily accessible means, then you must either (1) cause the Corresponding Source to be so available, or (2) arrange to deprive yourself of the benefit of the patent license for this particular work, or (3) arrange, in a manner consistent with the requirements of this License, to extend the patent license to downstream recipients. "Knowingly relying" means you have actual knowledge that, but for the patent license, your conveying the covered work in a country, or your recipient's use of the covered work in a country, would infringe one or more identifiable patents in that country that you have reason to believe are valid. If, pursuant to or in connection with a single transaction or arrangement, you convey, or propagate by procuring conveyance of, a covered work, and grant a patent license to some of the parties receiving the covered work authorizing them to use, propagate, modify or convey a specific copy of the covered work, then the patent license you grant is automatically extended to all recipients of the covered work and works based on it. A patent license is "discriminatory" if it does not include within the scope of its coverage, prohibits the exercise of, or is conditioned on the non-exercise of one or more of the rights that are specifically granted under this License. You may not convey a covered work if you are a party to an arrangement with a third party that is in the business of distributing software, under which you make payment to the third party based on the extent of your activity of conveying the work, and under which the third party grants, to any of the parties who would receive the covered work from you, a discriminatory patent license (a) in connection with copies of the covered work conveyed by you (or copies made from those copies), or (b) primarily for and in connection with specific products or compilations that contain the covered work, unless you entered into that arrangement, or that patent license was granted, prior to 28 March 2007. Nothing in this License shall be construed as excluding or limiting any implied license or other defenses to infringement that may otherwise be available to you under applicable patent law. 12. No Surrender of Others' Freedom. If conditions are imposed on you (whether by court order, agreement or otherwise) that contradict the conditions of this License, they do not excuse you from the conditions of this License. If you cannot convey a covered work so as to satisfy simultaneously your obligations under this License and any other pertinent obligations, then as a consequence you may not convey it at all. For example, if you agree to terms that obligate you to collect a royalty for further conveying from those to whom you convey the Program, the only way you could satisfy both those terms and this License would be to refrain entirely from conveying the Program. 13. Use with the GNU Affero General Public License. Notwithstanding any other provision of this License, you have permission to link or combine any covered work with a work licensed under version 3 of the GNU Affero General Public License into a single combined work, and to convey the resulting work. The terms of this License will continue to apply to the part which is the covered work, but the special requirements of the GNU Affero General Public License, section 13, concerning interaction through a network will apply to the combination as such. 14. Revised Versions of this License. The Free Software Foundation may publish revised and/or new versions of the GNU General Public License from time to time. Such new versions will be similar in spirit to the present version, but may differ in detail to address new problems or concerns. Each version is given a distinguishing version number. If the Program specifies that a certain numbered version of the GNU General Public License "or any later version" applies to it, you have the option of following the terms and conditions either of that numbered version or of any later version published by the Free Software Foundation. If the Program does not specify a version number of the GNU General Public License, you may choose any version ever published by the Free Software Foundation. If the Program specifies that a proxy can decide which future versions of the GNU General Public License can be used, that proxy's public statement of acceptance of a version permanently authorizes you to choose that version for the Program. Later license versions may give you additional or different permissions. However, no additional obligations are imposed on any author or copyright holder as a result of your choosing to follow a later version. 15. Disclaimer of Warranty. THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION. 16. Limitation of Liability. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. 17. Interpretation of Sections 15 and 16. If the disclaimer of warranty and limitation of liability provided above cannot be given local legal effect according to their terms, reviewing courts shall apply local law that most closely approximates an absolute waiver of all civil liability in connection with the Program, unless a warranty or assumption of liability accompanies a copy of the Program in return for a fee. END OF TERMS AND CONDITIONS =========================== How to Apply These Terms to Your New Programs ============================================= If you develop a new program, and you want it to be of the greatest possible use to the public, the best way to achieve this is to make it free software which everyone can redistribute and change under these terms. To do so, attach the following notices to the program. It is safest to attach them to the start of each source file to most effectively state the exclusion of warranty; and each file should have at least the "copyright" line and a pointer to where the full notice is found. ONE LINE TO GIVE THE PROGRAM'S NAME AND A BRIEF IDEA OF WHAT IT DOES. Copyright (C) YEAR NAME OF AUTHOR This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see `http://www.gnu.org/licenses/'. Also add information on how to contact you by electronic and paper mail. If the program does terminal interaction, make it output a short notice like this when it starts in an interactive mode: PROGRAM Copyright (C) YEAR NAME OF AUTHOR This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'. This is free software, and you are welcome to redistribute it under certain conditions; type `show c' for details. The hypothetical commands `show w' and `show c' should show the appropriate parts of the General Public License. Of course, your program's commands might be different; for a GUI interface, you would use an "about box". You should also get your employer (if you work as a programmer) or school, if any, to sign a "copyright disclaimer" for the program, if necessary. For more information on this, and how to apply and follow the GNU GPL, see `http://www.gnu.org/licenses/'. The GNU General Public License does not permit incorporating your program into proprietary programs. If your program is a subroutine library, you may consider it more useful to permit linking proprietary applications with the library. If this is what you want to do, use the GNU Lesser General Public License instead of this License. But first, please read `http://www.gnu.org/philosophy/why-not-lgpl.html'.  File: gfortran.info, Node: GNU Free Documentation License, Next: Funding, Prev: Copying, Up: Top GNU Free Documentation License ****************************** Version 1.2, November 2002 Copyright (C) 2000,2001,2002 Free Software Foundation, Inc. 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed. 0. PREAMBLE The purpose of this License is to make a manual, textbook, or other functional and useful document "free" in the sense of freedom: to assure everyone the effective freedom to copy and redistribute it, with or without modifying it, either commercially or noncommercially. Secondarily, this License preserves for the author and publisher a way to get credit for their work, while not being considered responsible for modifications made by others. This License is a kind of "copyleft", which means that derivative works of the document must themselves be free in the same sense. It complements the GNU General Public License, which is a copyleft license designed for free software. We have designed this License in order to use it for manuals for free software, because free software needs free documentation: a free program should come with manuals providing the same freedoms that the software does. But this License is not limited to software manuals; it can be used for any textual work, regardless of subject matter or whether it is published as a printed book. We recommend this License principally for works whose purpose is instruction or reference. 1. APPLICABILITY AND DEFINITIONS This License applies to any manual or other work, in any medium, that contains a notice placed by the copyright holder saying it can be distributed under the terms of this License. Such a notice grants a world-wide, royalty-free license, unlimited in duration, to use that work under the conditions stated herein. The "Document", below, refers to any such manual or work. Any member of the public is a licensee, and is addressed as "you". You accept the license if you copy, modify or distribute the work in a way requiring permission under copyright law. A "Modified Version" of the Document means any work containing the Document or a portion of it, either copied verbatim, or with modifications and/or translated into another language. A "Secondary Section" is a named appendix or a front-matter section of the Document that deals exclusively with the relationship of the publishers or authors of the Document to the Document's overall subject (or to related matters) and contains nothing that could fall directly within that overall subject. (Thus, if the Document is in part a textbook of mathematics, a Secondary Section may not explain any mathematics.) The relationship could be a matter of historical connection with the subject or with related matters, or of legal, commercial, philosophical, ethical or political position regarding them. The "Invariant Sections" are certain Secondary Sections whose titles are designated, as being those of Invariant Sections, in the notice that says that the Document is released under this License. If a section does not fit the above definition of Secondary then it is not allowed to be designated as Invariant. The Document may contain zero Invariant Sections. If the Document does not identify any Invariant Sections then there are none. The "Cover Texts" are certain short passages of text that are listed, as Front-Cover Texts or Back-Cover Texts, in the notice that says that the Document is released under this License. A Front-Cover Text may be at most 5 words, and a Back-Cover Text may be at most 25 words. A "Transparent" copy of the Document means a machine-readable copy, represented in a format whose specification is available to the general public, that is suitable for revising the document straightforwardly with generic text editors or (for images composed of pixels) generic paint programs or (for drawings) some widely available drawing editor, and that is suitable for input to text formatters or for automatic translation to a variety of formats suitable for input to text formatters. A copy made in an otherwise Transparent file format whose markup, or absence of markup, has been arranged to thwart or discourage subsequent modification by readers is not Transparent. An image format is not Transparent if used for any substantial amount of text. A copy that is not "Transparent" is called "Opaque". Examples of suitable formats for Transparent copies include plain ASCII without markup, Texinfo input format, LaTeX input format, SGML or XML using a publicly available DTD, and standard-conforming simple HTML, PostScript or PDF designed for human modification. Examples of transparent image formats include PNG, XCF and JPG. Opaque formats include proprietary formats that can be read and edited only by proprietary word processors, SGML or XML for which the DTD and/or processing tools are not generally available, and the machine-generated HTML, PostScript or PDF produced by some word processors for output purposes only. The "Title Page" means, for a printed book, the title page itself, plus such following pages as are needed to hold, legibly, the material this License requires to appear in the title page. For works in formats which do not have any title page as such, "Title Page" means the text near the most prominent appearance of the work's title, preceding the beginning of the body of the text. A section "Entitled XYZ" means a named subunit of the Document whose title either is precisely XYZ or contains XYZ in parentheses following text that translates XYZ in another language. (Here XYZ stands for a specific section name mentioned below, such as "Acknowledgements", "Dedications", "Endorsements", or "History".) To "Preserve the Title" of such a section when you modify the Document means that it remains a section "Entitled XYZ" according to this definition. The Document may include Warranty Disclaimers next to the notice which states that this License applies to the Document. These Warranty Disclaimers are considered to be included by reference in this License, but only as regards disclaiming warranties: any other implication that these Warranty Disclaimers may have is void and has no effect on the meaning of this License. 2. VERBATIM COPYING You may copy and distribute the Document in any medium, either commercially or noncommercially, provided that this License, the copyright notices, and the license notice saying this License applies to the Document are reproduced in all copies, and that you add no other conditions whatsoever to those of this License. You may not use technical measures to obstruct or control the reading or further copying of the copies you make or distribute. However, you may accept compensation in exchange for copies. If you distribute a large enough number of copies you must also follow the conditions in section 3. You may also lend copies, under the same conditions stated above, and you may publicly display copies. 3. COPYING IN QUANTITY If you publish printed copies (or copies in media that commonly have printed covers) of the Document, numbering more than 100, and the Document's license notice requires Cover Texts, you must enclose the copies in covers that carry, clearly and legibly, all these Cover Texts: Front-Cover Texts on the front cover, and Back-Cover Texts on the back cover. Both covers must also clearly and legibly identify you as the publisher of these copies. The front cover must present the full title with all words of the title equally prominent and visible. You may add other material on the covers in addition. Copying with changes limited to the covers, as long as they preserve the title of the Document and satisfy these conditions, can be treated as verbatim copying in other respects. If the required texts for either cover are too voluminous to fit legibly, you should put the first ones listed (as many as fit reasonably) on the actual cover, and continue the rest onto adjacent pages. If you publish or distribute Opaque copies of the Document numbering more than 100, you must either include a machine-readable Transparent copy along with each Opaque copy, or state in or with each Opaque copy a computer-network location from which the general network-using public has access to download using public-standard network protocols a complete Transparent copy of the Document, free of added material. If you use the latter option, you must take reasonably prudent steps, when you begin distribution of Opaque copies in quantity, to ensure that this Transparent copy will remain thus accessible at the stated location until at least one year after the last time you distribute an Opaque copy (directly or through your agents or retailers) of that edition to the public. It is requested, but not required, that you contact the authors of the Document well before redistributing any large number of copies, to give them a chance to provide you with an updated version of the Document. 4. MODIFICATIONS You may copy and distribute a Modified Version of the Document under the conditions of sections 2 and 3 above, provided that you release the Modified Version under precisely this License, with the Modified Version filling the role of the Document, thus licensing distribution and modification of the Modified Version to whoever possesses a copy of it. In addition, you must do these things in the Modified Version: A. Use in the Title Page (and on the covers, if any) a title distinct from that of the Document, and from those of previous versions (which should, if there were any, be listed in the History section of the Document). You may use the same title as a previous version if the original publisher of that version gives permission. B. List on the Title Page, as authors, one or more persons or entities responsible for authorship of the modifications in the Modified Version, together with at least five of the principal authors of the Document (all of its principal authors, if it has fewer than five), unless they release you from this requirement. C. State on the Title page the name of the publisher of the Modified Version, as the publisher. D. Preserve all the copyright notices of the Document. E. Add an appropriate copyright notice for your modifications adjacent to the other copyright notices. F. Include, immediately after the copyright notices, a license notice giving the public permission to use the Modified Version under the terms of this License, in the form shown in the Addendum below. G. Preserve in that license notice the full lists of Invariant Sections and required Cover Texts given in the Document's license notice. H. Include an unaltered copy of this License. I. Preserve the section Entitled "History", Preserve its Title, and add to it an item stating at least the title, year, new authors, and publisher of the Modified Version as given on the Title Page. If there is no section Entitled "History" in the Document, create one stating the title, year, authors, and publisher of the Document as given on its Title Page, then add an item describing the Modified Version as stated in the previous sentence. J. Preserve the network location, if any, given in the Document for public access to a Transparent copy of the Document, and likewise the network locations given in the Document for previous versions it was based on. These may be placed in the "History" section. You may omit a network location for a work that was published at least four years before the Document itself, or if the original publisher of the version it refers to gives permission. K. For any section Entitled "Acknowledgements" or "Dedications", Preserve the Title of the section, and preserve in the section all the substance and tone of each of the contributor acknowledgements and/or dedications given therein. L. Preserve all the Invariant Sections of the Document, unaltered in their text and in their titles. Section numbers or the equivalent are not considered part of the section titles. M. Delete any section Entitled "Endorsements". Such a section may not be included in the Modified Version. N. Do not retitle any existing section to be Entitled "Endorsements" or to conflict in title with any Invariant Section. O. Preserve any Warranty Disclaimers. If the Modified Version includes new front-matter sections or appendices that qualify as Secondary Sections and contain no material copied from the Document, you may at your option designate some or all of these sections as invariant. To do this, add their titles to the list of Invariant Sections in the Modified Version's license notice. These titles must be distinct from any other section titles. You may add a section Entitled "Endorsements", provided it contains nothing but endorsements of your Modified Version by various parties--for example, statements of peer review or that the text has been approved by an organization as the authoritative definition of a standard. You may add a passage of up to five words as a Front-Cover Text, and a passage of up to 25 words as a Back-Cover Text, to the end of the list of Cover Texts in the Modified Version. Only one passage of Front-Cover Text and one of Back-Cover Text may be added by (or through arrangements made by) any one entity. If the Document already includes a cover text for the same cover, previously added by you or by arrangement made by the same entity you are acting on behalf of, you may not add another; but you may replace the old one, on explicit permission from the previous publisher that added the old one. The author(s) and publisher(s) of the Document do not by this License give permission to use their names for publicity for or to assert or imply endorsement of any Modified Version. 5. COMBINING DOCUMENTS You may combine the Document with other documents released under this License, under the terms defined in section 4 above for modified versions, provided that you include in the combination all of the Invariant Sections of all of the original documents, unmodified, and list them all as Invariant Sections of your combined work in its license notice, and that you preserve all their Warranty Disclaimers. The combined work need only contain one copy of this License, and multiple identical Invariant Sections may be replaced with a single copy. If there are multiple Invariant Sections with the same name but different contents, make the title of each such section unique by adding at the end of it, in parentheses, the name of the original author or publisher of that section if known, or else a unique number. Make the same adjustment to the section titles in the list of Invariant Sections in the license notice of the combined work. In the combination, you must combine any sections Entitled "History" in the various original documents, forming one section Entitled "History"; likewise combine any sections Entitled "Acknowledgements", and any sections Entitled "Dedications". You must delete all sections Entitled "Endorsements." 6. COLLECTIONS OF DOCUMENTS You may make a collection consisting of the Document and other documents released under this License, and replace the individual copies of this License in the various documents with a single copy that is included in the collection, provided that you follow the rules of this License for verbatim copying of each of the documents in all other respects. You may extract a single document from such a collection, and distribute it individually under this License, provided you insert a copy of this License into the extracted document, and follow this License in all other respects regarding verbatim copying of that document. 7. AGGREGATION WITH INDEPENDENT WORKS A compilation of the Document or its derivatives with other separate and independent documents or works, in or on a volume of a storage or distribution medium, is called an "aggregate" if the copyright resulting from the compilation is not used to limit the legal rights of the compilation's users beyond what the individual works permit. When the Document is included in an aggregate, this License does not apply to the other works in the aggregate which are not themselves derivative works of the Document. If the Cover Text requirement of section 3 is applicable to these copies of the Document, then if the Document is less than one half of the entire aggregate, the Document's Cover Texts may be placed on covers that bracket the Document within the aggregate, or the electronic equivalent of covers if the Document is in electronic form. Otherwise they must appear on printed covers that bracket the whole aggregate. 8. TRANSLATION Translation is considered a kind of modification, so you may distribute translations of the Document under the terms of section 4. Replacing Invariant Sections with translations requires special permission from their copyright holders, but you may include translations of some or all Invariant Sections in addition to the original versions of these Invariant Sections. You may include a translation of this License, and all the license notices in the Document, and any Warranty Disclaimers, provided that you also include the original English version of this License and the original versions of those notices and disclaimers. In case of a disagreement between the translation and the original version of this License or a notice or disclaimer, the original version will prevail. If a section in the Document is Entitled "Acknowledgements", "Dedications", or "History", the requirement (section 4) to Preserve its Title (section 1) will typically require changing the actual title. 9. TERMINATION You may not copy, modify, sublicense, or distribute the Document except as expressly provided for under this License. Any other attempt to copy, modify, sublicense or distribute the Document is void, and will automatically terminate your rights under this License. However, parties who have received copies, or rights, from you under this License will not have their licenses terminated so long as such parties remain in full compliance. 10. FUTURE REVISIONS OF THIS LICENSE The Free Software Foundation may publish new, revised versions of the GNU Free Documentation License from time to time. Such new versions will be similar in spirit to the present version, but may differ in detail to address new problems or concerns. See `http://www.gnu.org/copyleft/'. Each version of the License is given a distinguishing version number. If the Document specifies that a particular numbered version of this License "or any later version" applies to it, you have the option of following the terms and conditions either of that specified version or of any later version that has been published (not as a draft) by the Free Software Foundation. If the Document does not specify a version number of this License, you may choose any version ever published (not as a draft) by the Free Software Foundation. ADDENDUM: How to use this License for your documents ==================================================== To use this License in a document you have written, include a copy of the License in the document and put the following copyright and license notices just after the title page: Copyright (C) YEAR YOUR NAME. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled ``GNU Free Documentation License''. If you have Invariant Sections, Front-Cover Texts and Back-Cover Texts, replace the "with...Texts." line with this: with the Invariant Sections being LIST THEIR TITLES, with the Front-Cover Texts being LIST, and with the Back-Cover Texts being LIST. If you have Invariant Sections without Cover Texts, or some other combination of the three, merge those two alternatives to suit the situation. If your document contains nontrivial examples of program code, we recommend releasing these examples in parallel under your choice of free software license, such as the GNU General Public License, to permit their use in free software.  File: gfortran.info, Node: Funding, Next: Option Index, Prev: GNU Free Documentation License, Up: Top Funding Free Software ********************* If you want to have more free software a few years from now, it makes sense for you to help encourage people to contribute funds for its development. The most effective approach known is to encourage commercial redistributors to donate. Users of free software systems can boost the pace of development by encouraging for-a-fee distributors to donate part of their selling price to free software developers--the Free Software Foundation, and others. The way to convince distributors to do this is to demand it and expect it from them. So when you compare distributors, judge them partly by how much they give to free software development. Show distributors they must compete to be the one who gives the most. To make this approach work, you must insist on numbers that you can compare, such as, "We will donate ten dollars to the Frobnitz project for each disk sold." Don't be satisfied with a vague promise, such as "A portion of the profits are donated," since it doesn't give a basis for comparison. Even a precise fraction "of the profits from this disk" is not very meaningful, since creative accounting and unrelated business decisions can greatly alter what fraction of the sales price counts as profit. If the price you pay is $50, ten percent of the profit is probably less than a dollar; it might be a few cents, or nothing at all. Some redistributors do development work themselves. This is useful too; but to keep everyone honest, you need to inquire how much they do, and what kind. Some kinds of development make much more long-term difference than others. For example, maintaining a separate version of a program contributes very little; maintaining the standard version of a program for the whole community contributes much. Easy new ports contribute little, since someone else would surely do them; difficult ports such as adding a new CPU to the GNU Compiler Collection contribute more; major new features or packages contribute the most. By establishing the idea that supporting further development is "the proper thing to do" when distributing free software for a fee, we can assure a steady flow of resources into making more free software. Copyright (C) 1994 Free Software Foundation, Inc. Verbatim copying and redistribution of this section is permitted without royalty; alteration is not permitted.  File: gfortran.info, Node: Option Index, Next: Keyword Index, Prev: Funding, Up: Top Option Index ************ `gfortran''s command line options are indexed here without any initial `-' or `--'. Where an option has both positive and negative forms (such as -foption and -fno-option), relevant entries in the manual are indexed under the most appropriate form; it may sometimes be useful to look up both forms. [index] * Menu: * backslash: Fortran Dialect Options. (line 47) * fall-intrinsics: Fortran Dialect Options. (line 18) * fbacktrace: Debugging Options. (line 31) * fblas-matmul-limit: Code Gen Options. (line 186) * fbounds-check: Code Gen Options. (line 130) * fconvert=CONVERSION: Runtime Options. (line 9) * fcray-pointer: Fortran Dialect Options. (line 90) * fd-lines-as-code: Fortran Dialect Options. (line 26) * fd-lines-as-comments: Fortran Dialect Options. (line 26) * fdefault-double-8: Fortran Dialect Options. (line 33) * fdefault-integer-8: Fortran Dialect Options. (line 36) * fdefault-real-8: Fortran Dialect Options. (line 40) * fdollar-ok: Fortran Dialect Options. (line 44) * fdump-core: Debugging Options. (line 38) * fdump-parse-tree: Debugging Options. (line 10) * fexternal-blas: Code Gen Options. (line 178) * ff2c: Code Gen Options. (line 25) * ffixed-line-length-N: Fortran Dialect Options. (line 61) * ffpe-trap=LIST: Debugging Options. (line 14) * ffree-form: Fortran Dialect Options. (line 12) * ffree-line-length-N: Fortran Dialect Options. (line 74) * fimplicit-none: Fortran Dialect Options. (line 85) * finit-character: Code Gen Options. (line 210) * finit-integer: Code Gen Options. (line 210) * finit-local-zero: Code Gen Options. (line 210) * finit-logical: Code Gen Options. (line 210) * finit-real: Code Gen Options. (line 210) * fintrinsic-modules-path DIR: Directory Options. (line 41) * fmax-errors=N: Error and Warning Options. (line 27) * fmax-identifier-length=N: Fortran Dialect Options. (line 81) * fmax-stack-var-size: Code Gen Options. (line 142) * fmax-subrecord-length=LENGTH: Runtime Options. (line 28) * fmodule-private: Fortran Dialect Options. (line 56) * fno-automatic: Code Gen Options. (line 15) * fno-fixed-form: Fortran Dialect Options. (line 12) * fno-underscoring: Code Gen Options. (line 54) * fopenmp: Fortran Dialect Options. (line 94) * fpack-derived: Code Gen Options. (line 156) * frange-check: Fortran Dialect Options. (line 102) * frecord-marker=LENGTH: Runtime Options. (line 20) * frecursive: Code Gen Options. (line 197) * frepack-arrays: Code Gen Options. (line 162) * fsecond-underscore: Code Gen Options. (line 113) * fshort-enums <1>: Fortran 2003 status. (line 20) * fshort-enums: Code Gen Options. (line 172) * fsign-zero: Runtime Options. (line 33) * fsyntax-only: Error and Warning Options. (line 33) * IDIR: Directory Options. (line 14) * JDIR: Directory Options. (line 31) * MDIR: Directory Options. (line 31) * pedantic: Error and Warning Options. (line 38) * pedantic-errors: Error and Warning Options. (line 56) * static-libgfortran: Link Options. (line 11) * std=STD option: Fortran Dialect Options. (line 114) * Waliasing: Error and Warning Options. (line 66) * Wall: Error and Warning Options. (line 60) * Wampersand: Error and Warning Options. (line 83) * Wcharacter-truncation: Error and Warning Options. (line 91) * Wconversion: Error and Warning Options. (line 94) * Werror: Error and Warning Options. (line 142) * Wimplicit-interface: Error and Warning Options. (line 97) * Wnonstd-intrinsics: Error and Warning Options. (line 103) * Wsurprising: Error and Warning Options. (line 107) * Wtabs: Error and Warning Options. (line 123) * Wunderflow: Error and Warning Options. (line 131) * Wunused-parameter: Error and Warning Options. (line 135)  File: gfortran.info, Node: Keyword Index, Prev: Option Index, Up: Top Keyword Index ************* [index] * Menu: * $: Fortran Dialect Options. (line 44) * %LOC: Argument list functions. (line 6) * %REF: Argument list functions. (line 6) * %VAL: Argument list functions. (line 6) * &: Error and Warning Options. (line 83) * [...]: Fortran 2003 status. (line 13) * ABORT: ABORT. (line 6) * ABS: ABS. (line 6) * absolute value: ABS. (line 6) * ACCESS: ACCESS. (line 6) * ACCESS='STREAM' I/O: Fortran 2003 status. (line 32) * ACHAR: ACHAR. (line 6) * ACOS: ACOS. (line 6) * ACOSH: ACOSH. (line 6) * adjust string <1>: ADJUSTR. (line 6) * adjust string: ADJUSTL. (line 6) * ADJUSTL: ADJUSTL. (line 6) * ADJUSTR: ADJUSTR. (line 6) * AIMAG: AIMAG. (line 6) * AINT: AINT. (line 6) * ALARM: ALARM. (line 6) * ALGAMA: LGAMMA. (line 6) * aliasing: Error and Warning Options. (line 66) * ALL: ALL. (line 6) * all warnings: Error and Warning Options. (line 60) * ALLOCATABLE components of derived types: Fortran 2003 status. (line 30) * ALLOCATABLE dummy arguments: Fortran 2003 status. (line 26) * ALLOCATABLE function results: Fortran 2003 status. (line 28) * ALLOCATED: ALLOCATED. (line 6) * allocation, moving: MOVE_ALLOC. (line 6) * allocation, status: ALLOCATED. (line 6) * ALOG: LOG. (line 6) * ALOG10: LOG10. (line 6) * AMAX0: MAX. (line 6) * AMAX1: MAX. (line 6) * AMIN0: MIN. (line 6) * AMIN1: MIN. (line 6) * AMOD: MOD. (line 6) * AND: AND. (line 6) * ANINT: ANINT. (line 6) * ANY: ANY. (line 6) * area hyperbolic cosine: ACOSH. (line 6) * area hyperbolic sine: ASINH. (line 6) * area hyperbolic tangent: ATANH. (line 6) * argument list functions: Argument list functions. (line 6) * arguments, to program <1>: IARGC. (line 6) * arguments, to program <2>: GET_COMMAND_ARGUMENT. (line 6) * arguments, to program <3>: GET_COMMAND. (line 6) * arguments, to program <4>: GETARG. (line 6) * arguments, to program: COMMAND_ARGUMENT_COUNT. (line 6) * array, add elements: SUM. (line 6) * array, apply condition <1>: ANY. (line 6) * array, apply condition: ALL. (line 6) * array, bounds checking: Code Gen Options. (line 130) * array, change dimensions: RESHAPE. (line 6) * array, combine arrays: MERGE. (line 6) * array, condition testing <1>: ANY. (line 6) * array, condition testing: ALL. (line 6) * array, conditionally add elements: SUM. (line 6) * array, conditionally count elements: COUNT. (line 6) * array, conditionally multiply elements: PRODUCT. (line 6) * array, constructors: Fortran 2003 status. (line 13) * array, count elements: SIZE. (line 6) * array, duplicate dimensions: SPREAD. (line 6) * array, duplicate elements: SPREAD. (line 6) * array, element counting: COUNT. (line 6) * array, gather elements: PACK. (line 6) * array, increase dimension <1>: UNPACK. (line 6) * array, increase dimension: SPREAD. (line 6) * array, indices of type real: Real array indices. (line 6) * array, location of maximum element: MAXLOC. (line 6) * array, location of minimum element: MINLOC. (line 6) * array, lower bound: LBOUND. (line 6) * array, maximum value: MAXVAL. (line 6) * array, merge arrays: MERGE. (line 6) * array, minimum value: MINVAL. (line 6) * array, multiply elements: PRODUCT. (line 6) * array, number of elements <1>: SIZE. (line 6) * array, number of elements: COUNT. (line 6) * array, packing: PACK. (line 6) * array, permutation: CSHIFT. (line 6) * array, product: PRODUCT. (line 6) * array, reduce dimension: PACK. (line 6) * array, rotate: CSHIFT. (line 6) * array, scatter elements: UNPACK. (line 6) * array, shape: SHAPE. (line 6) * array, shift: EOSHIFT. (line 6) * array, shift circularly: CSHIFT. (line 6) * array, size: SIZE. (line 6) * array, sum: SUM. (line 6) * array, transmogrify: RESHAPE. (line 6) * array, transpose: TRANSPOSE. (line 6) * array, unpacking: UNPACK. (line 6) * array, upper bound: UBOUND. (line 6) * ASCII collating sequence <1>: IACHAR. (line 6) * ASCII collating sequence: ACHAR. (line 6) * ASIN: ASIN. (line 6) * ASINH <1>: ATANH. (line 6) * ASINH: ASINH. (line 6) * ASSOCIATED: ASSOCIATED. (line 6) * association status: ASSOCIATED. (line 6) * association status, C pointer: C_ASSOCIATED. (line 6) * ATAN: ATAN. (line 6) * ATAN2: ATAN2. (line 6) * Authors: Contributors. (line 6) * backslash: Fortran Dialect Options. (line 47) * backtrace: Debugging Options. (line 31) * BESJ0: BESJ0. (line 6) * BESJ1: BESJ1. (line 6) * BESJN: BESJN. (line 6) * Bessel function, first kind <1>: BESJN. (line 6) * Bessel function, first kind <2>: BESJ1. (line 6) * Bessel function, first kind: BESJ0. (line 6) * Bessel function, second kind <1>: BESYN. (line 6) * Bessel function, second kind <2>: BESY1. (line 6) * Bessel function, second kind: BESY0. (line 6) * BESY0: BESY0. (line 6) * BESY1: BESY1. (line 6) * BESYN: BESYN. (line 6) * BIT_SIZE: BIT_SIZE. (line 6) * bits, clear: IBCLR. (line 6) * bits, extract: IBITS. (line 6) * bits, get: IBITS. (line 6) * bits, move <1>: TRANSFER. (line 6) * bits, move: MVBITS. (line 6) * bits, negate: NOT. (line 6) * bits, number of: BIT_SIZE. (line 6) * bits, set: IBSET. (line 6) * bits, shift: ISHFT. (line 6) * bits, shift circular: ISHFTC. (line 6) * bits, shift left: LSHIFT. (line 6) * bits, shift right: RSHIFT. (line 6) * bits, testing: BTEST. (line 6) * bits, unset: IBCLR. (line 6) * bitwise logical and <1>: IAND. (line 6) * bitwise logical and: AND. (line 6) * bitwise logical exclusive or <1>: XOR. (line 6) * bitwise logical exclusive or: IEOR. (line 6) * bitwise logical not: NOT. (line 6) * bitwise logical or <1>: OR. (line 6) * bitwise logical or: IOR. (line 6) * bounds checking: Code Gen Options. (line 130) * BOZ literal constants: BOZ literal constants. (line 6) * BTEST: BTEST. (line 6) * C_ASSOCIATED: C_ASSOCIATED. (line 6) * C_F_POINTER: C_F_POINTER. (line 6) * C_F_PROCPOINTER: C_F_PROCPOINTER. (line 6) * C_FUNLOC: C_FUNLOC. (line 6) * C_LOC: C_LOC. (line 6) * CABS: ABS. (line 6) * calling convention: Code Gen Options. (line 25) * CCOS: COS. (line 6) * CDABS: ABS. (line 6) * CDCOS: COS. (line 6) * CDEXP: EXP. (line 6) * CDLOG: LOG. (line 6) * CDSIN: SIN. (line 6) * CDSQRT: SQRT. (line 6) * ceiling: CEILING. (line 6) * CEILING: CEILING. (line 6) * ceiling: ANINT. (line 6) * CEXP: EXP. (line 6) * CHAR: CHAR. (line 6) * character set: Fortran Dialect Options. (line 44) * CHDIR: CHDIR. (line 6) * checking subscripts: Code Gen Options. (line 130) * CHMOD: CHMOD. (line 6) * clock ticks <1>: SYSTEM_CLOCK. (line 6) * clock ticks <2>: MCLOCK8. (line 6) * clock ticks: MCLOCK. (line 6) * CLOG: LOG. (line 6) * CMPLX: CMPLX. (line 6) * code generation, conventions: Code Gen Options. (line 6) * collating sequence, ASCII <1>: IACHAR. (line 6) * collating sequence, ASCII: ACHAR. (line 6) * command options: Invoking GNU Fortran. (line 6) * command-line arguments <1>: IARGC. (line 6) * command-line arguments <2>: GET_COMMAND_ARGUMENT. (line 6) * command-line arguments <3>: GET_COMMAND. (line 6) * command-line arguments <4>: GETARG. (line 6) * command-line arguments: COMMAND_ARGUMENT_COUNT. (line 6) * command-line arguments, number of <1>: IARGC. (line 6) * command-line arguments, number of: COMMAND_ARGUMENT_COUNT. (line 6) * COMMAND_ARGUMENT_COUNT: COMMAND_ARGUMENT_COUNT. (line 6) * COMPLEX: COMPLEX. (line 6) * complex conjugate: CONJG. (line 6) * complex numbers, conversion to <1>: DCMPLX. (line 6) * complex numbers, conversion to <2>: COMPLEX. (line 6) * complex numbers, conversion to: CMPLX. (line 6) * complex numbers, imaginary part: AIMAG. (line 6) * complex numbers, real part <1>: REAL. (line 6) * complex numbers, real part: DREAL. (line 6) * Conditional compilation: Preprocessing and conditional compilation. (line 6) * CONJG: CONJG. (line 6) * Contributing: Contributing. (line 6) * Contributors: Contributors. (line 6) * conversion: Error and Warning Options. (line 94) * conversion, to character: CHAR. (line 6) * conversion, to complex <1>: DCMPLX. (line 6) * conversion, to complex <2>: COMPLEX. (line 6) * conversion, to complex: CMPLX. (line 6) * conversion, to integer <1>: LONG. (line 6) * conversion, to integer <2>: INT8. (line 6) * conversion, to integer <3>: INT2. (line 6) * conversion, to integer <4>: INT. (line 6) * conversion, to integer <5>: ICHAR. (line 6) * conversion, to integer <6>: IACHAR. (line 6) * conversion, to integer: Implicitly convert LOGICAL and INTEGER values. (line 6) * conversion, to logical <1>: LOGICAL. (line 6) * conversion, to logical: Implicitly convert LOGICAL and INTEGER values. (line 6) * conversion, to real <1>: SNGL. (line 6) * conversion, to real <2>: REAL. (line 6) * conversion, to real <3>: FLOAT. (line 6) * conversion, to real <4>: DFLOAT. (line 6) * conversion, to real: DBLE. (line 6) * conversion, to string: CTIME. (line 6) * CONVERT specifier: CONVERT specifier. (line 6) * core, dump <1>: ABORT. (line 6) * core, dump: Debugging Options. (line 38) * COS: COS. (line 6) * COSH: COSH. (line 6) * cosine: COS. (line 6) * cosine, hyperbolic: COSH. (line 6) * cosine, hyperbolic, inverse: ACOSH. (line 6) * cosine, inverse: ACOS. (line 6) * COUNT: COUNT. (line 6) * CPP: Preprocessing and conditional compilation. (line 6) * CPU_TIME: CPU_TIME. (line 6) * Credits: Contributors. (line 6) * CSHIFT: CSHIFT. (line 6) * CSIN: SIN. (line 6) * CSQRT: SQRT. (line 6) * CTIME: CTIME. (line 6) * current date <1>: IDATE. (line 6) * current date <2>: FDATE. (line 6) * current date: DATE_AND_TIME. (line 6) * current time <1>: TIME8. (line 6) * current time <2>: TIME. (line 6) * current time <3>: ITIME. (line 6) * current time <4>: FDATE. (line 6) * current time: DATE_AND_TIME. (line 6) * DABS: ABS. (line 6) * DACOS: ACOS. (line 6) * DACOSH: ACOSH. (line 6) * DASIN: ASIN. (line 6) * DASINH <1>: ATANH. (line 6) * DASINH: ASINH. (line 6) * DATAN: ATAN. (line 6) * DATAN2: ATAN2. (line 6) * date, current <1>: IDATE. (line 6) * date, current <2>: FDATE. (line 6) * date, current: DATE_AND_TIME. (line 6) * DATE_AND_TIME: DATE_AND_TIME. (line 6) * DBESJ0: BESJ0. (line 6) * DBESJ1: BESJ1. (line 6) * DBESJN: BESJN. (line 6) * DBESY0: BESY0. (line 6) * DBESY1: BESY1. (line 6) * DBESYN: BESYN. (line 6) * DBLE: DBLE. (line 6) * DCMPLX: DCMPLX. (line 6) * DCONJG: CONJG. (line 6) * DCOS: COS. (line 6) * DCOSH: COSH. (line 6) * DDIM: DIM. (line 6) * debugging information options: Debugging Options. (line 6) * DECODE: ENCODE and DECODE statements. (line 6) * delayed execution <1>: SLEEP. (line 6) * delayed execution: ALARM. (line 6) * DEXP: EXP. (line 6) * DFLOAT: DFLOAT. (line 6) * DGAMMA: GAMMA. (line 6) * dialect options: Fortran Dialect Options. (line 6) * DIGITS: DIGITS. (line 6) * DIM: DIM. (line 6) * DIMAG: AIMAG. (line 6) * DINT: AINT. (line 6) * directive, INCLUDE: Directory Options. (line 6) * directory, options: Directory Options. (line 6) * directory, search paths for inclusion: Directory Options. (line 14) * division, modulo: MODULO. (line 6) * division, remainder: MOD. (line 6) * DLGAMA: LGAMMA. (line 6) * DLOG: LOG. (line 6) * DLOG10: LOG10. (line 6) * DMAX1: MAX. (line 6) * DMIN1: MIN. (line 6) * DMOD: MOD. (line 6) * DNINT: ANINT. (line 6) * dot product: DOT_PRODUCT. (line 6) * DOT_PRODUCT: DOT_PRODUCT. (line 6) * DPROD: DPROD. (line 6) * DREAL: DREAL. (line 6) * DSIGN: SIGN. (line 6) * DSIN: SIN. (line 6) * DSINH: SINH. (line 6) * DSQRT: SQRT. (line 6) * DTAN: TAN. (line 6) * DTANH: TANH. (line 6) * DTIME: DTIME. (line 6) * elapsed time <1>: SECOND. (line 6) * elapsed time <2>: SECNDS. (line 6) * elapsed time: DTIME. (line 6) * ENCODE: ENCODE and DECODE statements. (line 6) * ENUM statement: Fortran 2003 status. (line 20) * ENUMERATOR statement: Fortran 2003 status. (line 20) * environment variable <1>: GET_ENVIRONMENT_VARIABLE. (line 6) * environment variable <2>: GETENV. (line 6) * environment variable <3>: Runtime. (line 6) * environment variable: Environment Variables. (line 6) * EOSHIFT: EOSHIFT. (line 6) * EPSILON: EPSILON. (line 6) * ERF: ERF. (line 6) * ERFC: ERFC. (line 6) * error function: ERF. (line 6) * error function, complementary: ERFC. (line 6) * errors, limiting: Error and Warning Options. (line 27) * escape characters: Fortran Dialect Options. (line 47) * ETIME: ETIME. (line 6) * EXIT: EXIT. (line 6) * EXP: EXP. (line 6) * EXPONENT: EXPONENT. (line 6) * exponential function: EXP. (line 6) * exponential function, inverse <1>: LOG10. (line 6) * exponential function, inverse: LOG. (line 6) * expression size: SIZEOF. (line 6) * extensions: Extensions. (line 6) * extensions, implemented: Extensions implemented in GNU Fortran. (line 6) * extensions, not implemented: Extensions not implemented in GNU Fortran. (line 6) * f2c calling convention: Code Gen Options. (line 25) * Factorial function: GAMMA. (line 6) * FDATE: FDATE. (line 6) * FDL, GNU Free Documentation License: GNU Free Documentation License. (line 6) * FGET: FGET. (line 6) * FGETC: FGETC. (line 6) * file format, fixed: Fortran Dialect Options. (line 12) * file format, free: Fortran Dialect Options. (line 12) * file operation, file number: FNUM. (line 6) * file operation, flush: FLUSH. (line 6) * file operation, position <1>: FTELL. (line 6) * file operation, position: FSEEK. (line 6) * file operation, read character <1>: FGETC. (line 6) * file operation, read character: FGET. (line 6) * file operation, seek: FSEEK. (line 6) * file operation, write character <1>: FPUTC. (line 6) * file operation, write character: FPUT. (line 6) * file system, access mode: ACCESS. (line 6) * file system, change access mode: CHMOD. (line 6) * file system, create link <1>: SYMLNK. (line 6) * file system, create link: LINK. (line 6) * file system, file creation mask: UMASK. (line 6) * file system, file status <1>: STAT. (line 6) * file system, file status <2>: LSTAT. (line 6) * file system, file status: FSTAT. (line 6) * file system, hard link: LINK. (line 6) * file system, remove file: UNLINK. (line 6) * file system, rename file: RENAME. (line 6) * file system, soft link: SYMLNK. (line 6) * FLOAT: FLOAT. (line 6) * floating point, exponent: EXPONENT. (line 6) * floating point, fraction: FRACTION. (line 6) * floating point, nearest different: NEAREST. (line 6) * floating point, relative spacing <1>: SPACING. (line 6) * floating point, relative spacing: RRSPACING. (line 6) * floating point, scale: SCALE. (line 6) * floating point, set exponent: SET_EXPONENT. (line 6) * floor: FLOOR. (line 6) * FLOOR: FLOOR. (line 6) * floor: AINT. (line 6) * FLUSH: FLUSH. (line 6) * FLUSH statement: Fortran 2003 status. (line 16) * FNUM: FNUM. (line 6) * Fortran 77: GNU Fortran and G77. (line 6) * FPP: Preprocessing and conditional compilation. (line 6) * FPUT: FPUT. (line 6) * FPUTC: FPUTC. (line 6) * FRACTION: FRACTION. (line 6) * FREE: FREE. (line 6) * FSEEK: FSEEK. (line 6) * FSTAT: FSTAT. (line 6) * FTELL: FTELL. (line 6) * g77: GNU Fortran and G77. (line 6) * g77 calling convention: Code Gen Options. (line 25) * GAMMA <1>: LGAMMA. (line 6) * GAMMA: GAMMA. (line 6) * Gamma function: GAMMA. (line 6) * Gamma function, logarithm of: LGAMMA. (line 6) * GCC: GNU Fortran and GCC. (line 6) * GERROR: GERROR. (line 6) * GET_COMMAND: GET_COMMAND. (line 6) * GET_COMMAND_ARGUMENT: GET_COMMAND_ARGUMENT. (line 6) * GET_ENVIRONMENT_VARIABLE: GET_ENVIRONMENT_VARIABLE. (line 6) * GETARG: GETARG. (line 6) * GETCWD: GETCWD. (line 6) * GETENV: GETENV. (line 6) * GETGID: GETGID. (line 6) * GETLOG: GETLOG. (line 6) * GETPID: GETPID. (line 6) * GETUID: GETUID. (line 6) * GMTIME: GMTIME. (line 6) * GNU Compiler Collection: GNU Fortran and GCC. (line 6) * GNU Fortran command options: Invoking GNU Fortran. (line 6) * Hollerith constants: Hollerith constants support. (line 6) * HOSTNM: HOSTNM. (line 6) * HUGE: HUGE. (line 6) * hyperbolic arccosine: ACOSH. (line 6) * hyperbolic arcsine: ASINH. (line 6) * hyperbolic arctangent: ATANH. (line 6) * hyperbolic cosine: COSH. (line 6) * hyperbolic function, cosine: COSH. (line 6) * hyperbolic function, cosine, inverse: ACOSH. (line 6) * hyperbolic function, sine: SINH. (line 6) * hyperbolic function, sine, inverse: ASINH. (line 6) * hyperbolic function, tangent: TANH. (line 6) * hyperbolic function, tangent, inverse: ATANH. (line 6) * hyperbolic sine: SINH. (line 6) * hyperbolic tangent: TANH. (line 6) * I/O item lists: I/O item lists. (line 6) * IABS: ABS. (line 6) * IACHAR: IACHAR. (line 6) * IAND: IAND. (line 6) * IARGC: IARGC. (line 6) * IBCLR: IBCLR. (line 6) * IBITS: IBITS. (line 6) * IBSET: IBSET. (line 6) * ICHAR: ICHAR. (line 6) * IDATE: IDATE. (line 6) * IDIM: DIM. (line 6) * IDINT: INT. (line 6) * IDNINT: NINT. (line 6) * IEEE, ISNAN: ISNAN. (line 6) * IEOR: IEOR. (line 6) * IERRNO: IERRNO. (line 6) * IFIX: INT. (line 6) * IMAG: AIMAG. (line 6) * IMAGPART: AIMAG. (line 6) * IMPORT statement: Fortran 2003 status. (line 43) * INCLUDE directive: Directory Options. (line 6) * inclusion, directory search paths for: Directory Options. (line 14) * INDEX: INDEX intrinsic. (line 6) * INT: INT. (line 6) * INT2: INT2. (line 6) * INT8: INT8. (line 6) * integer kind: SELECTED_INT_KIND. (line 6) * intrinsic Modules: Intrinsic Modules. (line 6) * intrinsic procedures: Intrinsic Procedures. (line 6) * Introduction: Top. (line 6) * IOMSG= specifier: Fortran 2003 status. (line 18) * IOR: IOR. (line 6) * IOSTAT, end of file: IS_IOSTAT_END. (line 6) * IOSTAT, end of record: IS_IOSTAT_EOR. (line 6) * IRAND: IRAND. (line 6) * IS_IOSTAT_END: IS_IOSTAT_END. (line 6) * IS_IOSTAT_EOR: IS_IOSTAT_EOR. (line 6) * ISATTY: ISATTY. (line 6) * ISHFT: ISHFT. (line 6) * ISHFTC: ISHFTC. (line 6) * ISIGN: SIGN. (line 6) * ISNAN: ISNAN. (line 6) * ISO C Bindings: Fortran 2003 status. (line 52) * ISO_FORTRAN_ENV statement: Fortran 2003 status. (line 46) * ITIME: ITIME. (line 6) * KILL: KILL. (line 6) * kind: KIND. (line 6) * KIND: KIND. (line 6) * kind, integer: SELECTED_INT_KIND. (line 6) * kind, old-style: Old-style kind specifications. (line 6) * kind, real: SELECTED_REAL_KIND. (line 6) * language, dialect options: Fortran Dialect Options. (line 6) * LBOUND: LBOUND. (line 6) * LEN: LEN. (line 6) * LEN_TRIM: LEN_TRIM. (line 6) * lexical comparison of strings <1>: LLT. (line 6) * lexical comparison of strings <2>: LLE. (line 6) * lexical comparison of strings <3>: LGT. (line 6) * lexical comparison of strings: LGE. (line 6) * LGE: LGE. (line 6) * LGT: LGT. (line 6) * libf2c calling convention: Code Gen Options. (line 25) * limits, largest number: HUGE. (line 6) * limits, smallest number: TINY. (line 6) * LINK: LINK. (line 6) * linking, static: Link Options. (line 6) * LLE: LLE. (line 6) * LLT: LLT. (line 6) * LNBLNK: LNBLNK. (line 6) * LOC: LOC. (line 6) * location of a variable in memory: LOC. (line 6) * LOG: LOG. (line 6) * LOG10: LOG10. (line 6) * logarithmic function <1>: LOG10. (line 6) * logarithmic function: LOG. (line 6) * logarithmic function, inverse: EXP. (line 6) * LOGICAL: LOGICAL. (line 6) * logical and, bitwise <1>: IAND. (line 6) * logical and, bitwise: AND. (line 6) * logical exclusive or, bitwise <1>: XOR. (line 6) * logical exclusive or, bitwise: IEOR. (line 6) * logical not, bitwise: NOT. (line 6) * logical or, bitwise <1>: OR. (line 6) * logical or, bitwise: IOR. (line 6) * login name: GETLOG. (line 6) * LONG: LONG. (line 6) * LSHIFT: LSHIFT. (line 6) * LSTAT: LSTAT. (line 6) * LTIME: LTIME. (line 6) * MALLOC: MALLOC. (line 6) * MATMUL: MATMUL. (line 6) * matrix multiplication: MATMUL. (line 6) * matrix, transpose: TRANSPOSE. (line 6) * MAX: MAX. (line 6) * MAX0: MAX. (line 6) * MAX1: MAX. (line 6) * MAXEXPONENT: MAXEXPONENT. (line 6) * maximum value <1>: MAXVAL. (line 6) * maximum value: MAX. (line 6) * MAXLOC: MAXLOC. (line 6) * MAXVAL: MAXVAL. (line 6) * MCLOCK: MCLOCK. (line 6) * MCLOCK8: MCLOCK8. (line 6) * MERGE: MERGE. (line 6) * messages, error: Error and Warning Options. (line 6) * messages, warning: Error and Warning Options. (line 6) * MIN: MIN. (line 6) * MIN0: MIN. (line 6) * MIN1: MIN. (line 6) * MINEXPONENT: MINEXPONENT. (line 6) * minimum value <1>: MINVAL. (line 6) * minimum value: MIN. (line 6) * MINLOC: MINLOC. (line 6) * MINVAL: MINVAL. (line 6) * MOD: MOD. (line 6) * model representation, base: RADIX. (line 6) * model representation, epsilon: EPSILON. (line 6) * model representation, largest number: HUGE. (line 6) * model representation, maximum exponent: MAXEXPONENT. (line 6) * model representation, minimum exponent: MINEXPONENT. (line 6) * model representation, precision: PRECISION. (line 6) * model representation, radix: RADIX. (line 6) * model representation, range: RANGE. (line 6) * model representation, significant digits: DIGITS. (line 6) * model representation, smallest number: TINY. (line 6) * module entities: Fortran Dialect Options. (line 56) * module search path: Directory Options. (line 14) * modulo: MODULO. (line 6) * MODULO: MODULO. (line 6) * MOVE_ALLOC: MOVE_ALLOC. (line 6) * moving allocation: MOVE_ALLOC. (line 6) * multiply array elements: PRODUCT. (line 6) * MVBITS: MVBITS. (line 6) * Namelist: Extensions to namelist. (line 6) * NEAREST: NEAREST. (line 6) * NEW_LINE: NEW_LINE. (line 6) * newline: NEW_LINE. (line 6) * NINT: NINT. (line 6) * NOT: NOT. (line 6) * NULL: NULL. (line 6) * OpenMP <1>: OpenMP. (line 6) * OpenMP: Fortran Dialect Options. (line 94) * operators, unary: Unary operators. (line 6) * options, code generation: Code Gen Options. (line 6) * options, debugging: Debugging Options. (line 6) * options, dialect: Fortran Dialect Options. (line 6) * options, directory search: Directory Options. (line 6) * options, errors: Error and Warning Options. (line 6) * options, fortran dialect: Fortran Dialect Options. (line 12) * options, gfortran command: Invoking GNU Fortran. (line 6) * options, linking: Link Options. (line 6) * options, negative forms: Invoking GNU Fortran. (line 13) * options, run-time: Code Gen Options. (line 6) * options, runtime: Runtime Options. (line 6) * options, warnings: Error and Warning Options. (line 6) * OR: OR. (line 6) * output, newline: NEW_LINE. (line 6) * PACK: PACK. (line 6) * paths, search: Directory Options. (line 14) * PERROR: PERROR. (line 6) * pointer, C address of pointers: C_F_PROCPOINTER. (line 6) * pointer, C address of procedures: C_FUNLOC. (line 6) * pointer, C association status: C_ASSOCIATED. (line 6) * pointer, convert C to Fortran: C_F_POINTER. (line 6) * pointer, cray <1>: MALLOC. (line 6) * pointer, cray: FREE. (line 6) * pointer, Cray: Cray pointers. (line 6) * pointer, disassociated: NULL. (line 6) * pointer, status <1>: NULL. (line 6) * pointer, status: ASSOCIATED. (line 6) * positive difference: DIM. (line 6) * PRECISION: PRECISION. (line 6) * Preprocessing: Preprocessing and conditional compilation. (line 6) * PRESENT: PRESENT. (line 6) * private: Fortran Dialect Options. (line 56) * procedure pointer, convert C to Fortran: C_LOC. (line 6) * process id: GETPID. (line 6) * PRODUCT: PRODUCT. (line 6) * product, double-precision: DPROD. (line 6) * product, matrix: MATMUL. (line 6) * product, vector: DOT_PRODUCT. (line 6) * program termination: EXIT. (line 6) * program termination, with core dump: ABORT. (line 6) * PROTECTED statement: Fortran 2003 status. (line 37) * RADIX: RADIX. (line 6) * RAN: RAN. (line 6) * RAND: RAND. (line 6) * random number generation <1>: RANDOM_NUMBER. (line 6) * random number generation <2>: RAND. (line 6) * random number generation <3>: RAN. (line 6) * random number generation: IRAND. (line 6) * random number generation, seeding <1>: SRAND. (line 6) * random number generation, seeding: RANDOM_SEED. (line 6) * RANDOM_NUMBER: RANDOM_NUMBER. (line 6) * RANDOM_SEED: RANDOM_SEED. (line 6) * RANGE: RANGE. (line 6) * range checking: Code Gen Options. (line 130) * read character, stream mode <1>: FGETC. (line 6) * read character, stream mode: FGET. (line 6) * REAL: REAL. (line 6) * real kind: SELECTED_REAL_KIND. (line 6) * real number, exponent: EXPONENT. (line 6) * real number, fraction: FRACTION. (line 6) * real number, nearest different: NEAREST. (line 6) * real number, relative spacing <1>: SPACING. (line 6) * real number, relative spacing: RRSPACING. (line 6) * real number, scale: SCALE. (line 6) * real number, set exponent: SET_EXPONENT. (line 6) * REALPART: REAL. (line 6) * RECORD: STRUCTURE and RECORD. (line 6) * remainder: MOD. (line 6) * RENAME: RENAME. (line 6) * repacking arrays: Code Gen Options. (line 162) * REPEAT: REPEAT. (line 6) * RESHAPE: RESHAPE. (line 6) * root: SQRT. (line 6) * rounding, ceiling <1>: CEILING. (line 6) * rounding, ceiling: ANINT. (line 6) * rounding, floor <1>: FLOOR. (line 6) * rounding, floor: AINT. (line 6) * rounding, nearest whole number: NINT. (line 6) * RRSPACING: RRSPACING. (line 6) * RSHIFT: RSHIFT. (line 6) * SAVE statement: Code Gen Options. (line 15) * SCALE: SCALE. (line 6) * SCAN: SCAN. (line 6) * search path: Directory Options. (line 6) * search paths, for included files: Directory Options. (line 14) * SECNDS: SECNDS. (line 6) * SECOND: SECOND. (line 6) * seeding a random number generator <1>: SRAND. (line 6) * seeding a random number generator: RANDOM_SEED. (line 6) * SELECTED_INT_KIND: SELECTED_INT_KIND. (line 6) * SELECTED_REAL_KIND: SELECTED_REAL_KIND. (line 6) * SET_EXPONENT: SET_EXPONENT. (line 6) * SHAPE: SHAPE. (line 6) * SHORT: INT2. (line 6) * SIGN: SIGN. (line 6) * sign copying: SIGN. (line 6) * SIGNAL: SIGNAL. (line 6) * SIN: SIN. (line 6) * sine: SIN. (line 6) * sine, hyperbolic: SINH. (line 6) * sine, hyperbolic, inverse: ASINH. (line 6) * sine, inverse: ASIN. (line 6) * SINH: SINH. (line 6) * SIZE: SIZE. (line 6) * size of a variable, in bits: BIT_SIZE. (line 6) * size of an expression: SIZEOF. (line 6) * SIZEOF: SIZEOF. (line 6) * SLEEP: SLEEP. (line 6) * SNGL: SNGL. (line 6) * SPACING: SPACING. (line 6) * SPREAD: SPREAD. (line 6) * SQRT: SQRT. (line 6) * square-root: SQRT. (line 6) * SRAND: SRAND. (line 6) * Standards: Standards. (line 6) * STAT: STAT. (line 6) * statement, ENUM: Fortran 2003 status. (line 20) * statement, ENUMERATOR: Fortran 2003 status. (line 20) * statement, FLUSH: Fortran 2003 status. (line 16) * statement, IMPORT: Fortran 2003 status. (line 43) * statement, ISO_FORTRAN_ENV: Fortran 2003 status. (line 46) * statement, PROTECTED: Fortran 2003 status. (line 37) * statement, SAVE: Code Gen Options. (line 15) * statement, USE, INTRINSIC: Fortran 2003 status. (line 46) * statement, VALUE: Fortran 2003 status. (line 39) * statement, VOLATILE: Fortran 2003 status. (line 41) * STREAM I/O: Fortran 2003 status. (line 32) * stream mode, read character <1>: FGETC. (line 6) * stream mode, read character: FGET. (line 6) * stream mode, write character <1>: FPUTC. (line 6) * stream mode, write character: FPUT. (line 6) * string, adjust left: ADJUSTL. (line 6) * string, adjust right: ADJUSTR. (line 6) * string, comparison <1>: LLT. (line 6) * string, comparison <2>: LLE. (line 6) * string, comparison <3>: LGT. (line 6) * string, comparison: LGE. (line 6) * string, concatenate: REPEAT. (line 6) * string, find missing set: VERIFY. (line 6) * string, find non-blank character: LNBLNK. (line 6) * string, find subset: SCAN. (line 6) * string, find substring: INDEX intrinsic. (line 6) * string, length: LEN. (line 6) * string, length, without trailing whitespace: LEN_TRIM. (line 6) * string, remove trailing whitespace: TRIM. (line 6) * string, repeat: REPEAT. (line 6) * STRUCTURE: STRUCTURE and RECORD. (line 6) * structure packing: Code Gen Options. (line 156) * subscript checking: Code Gen Options. (line 130) * substring position: INDEX intrinsic. (line 6) * SUM: SUM. (line 6) * sum array elements: SUM. (line 6) * suppressing warnings: Error and Warning Options. (line 6) * symbol names: Fortran Dialect Options. (line 44) * symbol names, transforming: Code Gen Options. (line 54) * symbol names, underscores: Code Gen Options. (line 54) * SYMLNK: SYMLNK. (line 6) * syntax checking: Error and Warning Options. (line 33) * SYSTEM: SYSTEM. (line 6) * system, error handling <1>: PERROR. (line 6) * system, error handling <2>: IERRNO. (line 6) * system, error handling: GERROR. (line 6) * system, group id: GETGID. (line 6) * system, host name: HOSTNM. (line 6) * system, login name: GETLOG. (line 6) * system, process id: GETPID. (line 6) * system, signal handling: SIGNAL. (line 6) * system, system call: SYSTEM. (line 6) * system, terminal <1>: TTYNAM. (line 6) * system, terminal: ISATTY. (line 6) * system, user id: GETUID. (line 6) * system, working directory <1>: GETCWD. (line 6) * system, working directory: CHDIR. (line 6) * SYSTEM_CLOCK: SYSTEM_CLOCK. (line 6) * tabulators: Error and Warning Options. (line 123) * TAN: TAN. (line 6) * tangent: TAN. (line 6) * tangent, hyperbolic: TANH. (line 6) * tangent, hyperbolic, inverse: ATANH. (line 6) * tangent, inverse <1>: ATAN2. (line 6) * tangent, inverse: ATAN. (line 6) * TANH: TANH. (line 6) * terminate program: EXIT. (line 6) * terminate program, with core dump: ABORT. (line 6) * TIME: TIME. (line 6) * time, clock ticks <1>: SYSTEM_CLOCK. (line 6) * time, clock ticks <2>: MCLOCK8. (line 6) * time, clock ticks: MCLOCK. (line 6) * time, conversion to GMT info: GMTIME. (line 6) * time, conversion to local time info: LTIME. (line 6) * time, conversion to string: CTIME. (line 6) * time, current <1>: TIME8. (line 6) * time, current <2>: TIME. (line 6) * time, current <3>: ITIME. (line 6) * time, current <4>: FDATE. (line 6) * time, current: DATE_AND_TIME. (line 6) * time, elapsed <1>: SECOND. (line 6) * time, elapsed <2>: SECNDS. (line 6) * time, elapsed <3>: ETIME. (line 6) * time, elapsed <4>: DTIME. (line 6) * time, elapsed: CPU_TIME. (line 6) * TIME8: TIME8. (line 6) * TINY: TINY. (line 6) * TR 15581: Fortran 2003 status. (line 25) * trace: Debugging Options. (line 31) * TRANSFER: TRANSFER. (line 6) * transforming symbol names: Code Gen Options. (line 54) * transpose: TRANSPOSE. (line 6) * TRANSPOSE: TRANSPOSE. (line 6) * trigonometric function, cosine: COS. (line 6) * trigonometric function, cosine, inverse: ACOS. (line 6) * trigonometric function, sine: SIN. (line 6) * trigonometric function, sine, inverse: ASIN. (line 6) * trigonometric function, tangent: TAN. (line 6) * trigonometric function, tangent, inverse <1>: ATAN2. (line 6) * trigonometric function, tangent, inverse: ATAN. (line 6) * TRIM: TRIM. (line 6) * TTYNAM: TTYNAM. (line 6) * type cast: TRANSFER. (line 6) * UBOUND: UBOUND. (line 6) * UMASK: UMASK. (line 6) * underflow: Error and Warning Options. (line 131) * underscore: Code Gen Options. (line 54) * UNLINK: UNLINK. (line 6) * UNPACK: UNPACK. (line 6) * unused parameter: Error and Warning Options. (line 135) * USE, INTRINSIC statement: Fortran 2003 status. (line 46) * user id: GETUID. (line 6) * VALUE statement: Fortran 2003 status. (line 39) * vector product: DOT_PRODUCT. (line 6) * VERIFY: VERIFY. (line 6) * VOLATILE statement: Fortran 2003 status. (line 41) * warnings, aliasing: Error and Warning Options. (line 66) * warnings, all: Error and Warning Options. (line 60) * warnings, ampersand: Error and Warning Options. (line 83) * warnings, character truncation: Error and Warning Options. (line 91) * warnings, conversion: Error and Warning Options. (line 94) * warnings, implicit interface: Error and Warning Options. (line 97) * warnings, non-standard intrinsics: Error and Warning Options. (line 103) * warnings, suppressing: Error and Warning Options. (line 6) * warnings, suspicious code: Error and Warning Options. (line 107) * warnings, tabs: Error and Warning Options. (line 123) * warnings, to errors: Error and Warning Options. (line 142) * warnings, underflow: Error and Warning Options. (line 131) * warnings, unused parameter: Error and Warning Options. (line 135) * write character, stream mode <1>: FPUTC. (line 6) * write character, stream mode: FPUT. (line 6) * XOR: XOR. (line 6) * ZABS: ABS. (line 6) * ZCOS: COS. (line 6) * ZEXP: EXP. (line 6) * ZLOG: LOG. (line 6) * ZSIN: SIN. (line 6) * ZSQRT: SQRT. (line 6)  Tag Table: Node: Top2062 Node: Introduction3279 Node: About GNU Fortran4024 Node: GNU Fortran and GCC8082 Node: Preprocessing and conditional compilation10172 Node: GNU Fortran and G7711613 Node: Project Status12186 Node: Standards14684 Node: Invoking GNU Fortran15341 Node: Option Summary17001 Node: Fortran Dialect Options19895 Node: Error and Warning Options25638 Node: Debugging Options31803 Node: Directory Options33969 Node: Link Options35496 Node: Runtime Options36120 Node: Code Gen Options37823 Node: Environment Variables48390 Node: Runtime48993 Node: GFORTRAN_STDIN_UNIT50212 Node: GFORTRAN_STDOUT_UNIT50579 Node: GFORTRAN_STDERR_UNIT50980 Node: GFORTRAN_USE_STDERR51378 Node: GFORTRAN_TMPDIR51823 Node: GFORTRAN_UNBUFFERED_ALL52264 Node: GFORTRAN_UNBUFFERED_PRECONNECTED52787 Node: GFORTRAN_SHOW_LOCUS53428 Node: GFORTRAN_OPTIONAL_PLUS53922 Node: GFORTRAN_DEFAULT_RECL54397 Node: GFORTRAN_LIST_SEPARATOR54888 Node: GFORTRAN_CONVERT_UNIT55497 Node: GFORTRAN_ERROR_DUMPCORE58372 Node: GFORTRAN_ERROR_BACKTRACE58919 Node: Fortran 2003 status59470 Node: Extensions61139 Node: Extensions implemented in GNU Fortran61733 Node: Old-style kind specifications63053 Node: Old-style variable initialization63918 Node: Extensions to namelist65230 Node: X format descriptor without count field67226 Node: Commas in FORMAT specifications67753 Node: Missing period in FORMAT specifications68270 Node: I/O item lists68832 Node: BOZ literal constants69221 Node: Real array indices71790 Node: Unary operators72087 Node: Implicitly convert LOGICAL and INTEGER values72501 Node: Hollerith constants support73461 Node: Cray pointers75233 Node: CONVERT specifier80643 Node: OpenMP82645 Node: Argument list functions84899 Node: Extensions not implemented in GNU Fortran86493 Node: STRUCTURE and RECORD87344 Node: ENCODE and DECODE statements89401 Node: Intrinsic Procedures90719 Node: Introduction to Intrinsics104011 Node: ABORT106324 Node: ABS107027 Node: ACCESS108519 Node: ACHAR110408 Node: 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INT2232902 Node: INT8233682 Node: IOR234409 Node: IRAND235262 Node: IS_IOSTAT_END236617 Node: IS_IOSTAT_EOR237703 Node: ISATTY238819 Node: ISHFT239606 Node: ISHFTC240588 Node: ISNAN241809 Node: ITIME242557 Node: KILL243573 Node: KIND244488 Node: LBOUND245326 Node: LEN246610 Node: LEN_TRIM247676 Node: LGAMMA248635 Node: LGE249697 Node: LGT251000 Node: LINK252270 Node: LLE253305 Node: LLT254602 Node: LNBLNK255865 Node: LOC256644 Node: LOG257375 Node: LOG10258577 Node: LOGICAL259443 Node: LONG260270 Node: LSHIFT261041 Node: LSTAT262004 Node: LTIME263165 Node: MALLOC264644 Node: MATMUL266308 Node: MAX267495 Node: MAXEXPONENT269008 Node: MAXLOC269817 Node: MAXVAL271950 Node: MCLOCK273742 Node: MCLOCK8274745 Node: MERGE275959 Node: MIN276720 Node: MINEXPONENT278230 Node: MINLOC278853 Node: MINVAL280986 Node: MOD282752 Node: MODULO284129 Node: MOVE_ALLOC285336 Node: MVBITS286394 Node: NEAREST287477 Node: NEW_LINE288593 Node: NINT289378 Node: NOT290398 Node: NULL290980 Node: OR291864 Node: 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Node: UMASK352505 Node: UNLINK353093 Node: UNPACK354070 Node: VERIFY355350 Node: XOR357047 Node: Intrinsic Modules358219 Node: Contributing363045 Node: Contributors363897 Node: Projects365520 Node: Proposed Extensions366323 Node: Copying368374 Node: GNU Free Documentation License405938 Node: Funding428350 Node: Option Index430875 Node: Keyword Index438476  End Tag Table