diff options
Diffstat (limited to 'gcc-4.4.3/libstdc++-v3/doc/xml/manual/diagnostics.xml')
| -rw-r--r-- | gcc-4.4.3/libstdc++-v3/doc/xml/manual/diagnostics.xml | 130 |
1 files changed, 130 insertions, 0 deletions
diff --git a/gcc-4.4.3/libstdc++-v3/doc/xml/manual/diagnostics.xml b/gcc-4.4.3/libstdc++-v3/doc/xml/manual/diagnostics.xml new file mode 100644 index 000000000..ebdc6c7a2 --- /dev/null +++ b/gcc-4.4.3/libstdc++-v3/doc/xml/manual/diagnostics.xml @@ -0,0 +1,130 @@ +<?xml version='1.0'?> +<!DOCTYPE part PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" + "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" +[ ]> + +<part id="manual.diagnostics" xreflabel="Diagnostics"> +<?dbhtml filename="diagnostics.html"?> + +<partinfo> + <keywordset> + <keyword> + ISO C++ + </keyword> + <keyword> + library + </keyword> + </keywordset> +</partinfo> + +<title> + Diagnostics + <indexterm><primary>Diagnostics</primary></indexterm> +</title> + +<chapter id="manual.diagnostics.exceptions" xreflabel="Exceptions"> + <?dbhtml filename="exceptions.html"?> + <title>Exceptions</title> + + <sect1 id="manual.diagnostics.exceptions.hierarchy" xreflabel="Exception Classes"> + <title>Exception Classes</title> + <para> + All exception objects are defined in one of the standard header + files: <filename>exception</filename>, + <filename>stdexcept</filename>, <filename>new</filename>, and + <filename>typeinfo</filename>. + </para> + + <para> + The base exception object is <classname>exception</classname>, + located in <filename>exception</filename>. This object has no + <classname>string</classname> member. + </para> + + <para> + Derived from this are several classes that may have a + <classname>string</classname> member: a full hierarchy can be + found in the <ulink url="http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/a00233.html">source documentation</ulink>. + </para> + + </sect1> + <sect1 id="manual.diagnostics.exceptions.data" xreflabel="Adding Data to Exceptions"> + <title>Adding Data to Exceptions</title> + <para> + The standard exception classes carry with them a single string as + data (usually describing what went wrong or where the 'throw' took + place). It's good to remember that you can add your own data to + these exceptions when extending the hierarchy: + </para> + <programlisting> + struct My_Exception : public std::runtime_error + { + public: + My_Exception (const string& whatarg) + : std::runtime_error(whatarg), e(errno), id(GetDataBaseID()) { } + int errno_at_time_of_throw() const { return e; } + DBID id_of_thing_that_threw() const { return id; } + protected: + int e; + DBID id; // some user-defined type + }; + </programlisting> + + </sect1> + <sect1 id="manual.diagnostics.exceptions.cancellation" xreflabel="Cancellation"> + <title>Cancellation</title> + <para> + </para> + </sect1> +</chapter> + +<chapter id="manual.diagnostics.concept_checking" xreflabel="Concept Checking"> + <title>Concept Checking</title> + <para> + In 1999, SGI added <quote>concept checkers</quote> to their + implementation of the STL: code which checked the template + parameters of instantiated pieces of the STL, in order to insure + that the parameters being used met the requirements of the + standard. For example, the Standard requires that types passed as + template parameters to <classname>vector</classname> be + "Assignable" (which means what you think it means). The + checking was done during compilation, and none of the code was + executed at runtime. + </para> + <para> + Unfortunately, the size of the compiler files grew significantly + as a result. The checking code itself was cumbersome. And bugs + were found in it on more than one occasion. + </para> + <para> + The primary author of the checking code, Jeremy Siek, had already + started work on a replacement implementation. The new code has been + formally reviewed and accepted into + <ulink url="http://www.boost.org/libs/concept_check/concept_check.htm">the + Boost libraries</ulink>, and we are pleased to incorporate it into the + GNU C++ library. + </para> + <para> + The new version imposes a much smaller space overhead on the generated + object file. The checks are also cleaner and easier to read and + understand. + </para> + + <para> + They are off by default for all versions of GCC. + They can be enabled at configure time with + <ulink url="../configopts.html"><literal>--enable-concept-checks</literal></ulink>. + You can enable them on a per-translation-unit basis with + <literal>-D_GLIBCXX_CONCEPT_CHECKS</literal>. + </para> + + <para> + Please note that the upcoming C++ standard has first-class + support for template parameter constraints based on concepts in the core + language. This will obviate the need for the library-simulated concept + checking described above. + </para> + +</chapter> + +</part> |