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diff --git a/gcc-4.4.3/libstdc++-v3/doc/html/manual/bk01pt11ch28s02.html b/gcc-4.4.3/libstdc++-v3/doc/html/manual/bk01pt11ch28s02.html deleted file mode 100644 index 5e668931c..000000000 --- a/gcc-4.4.3/libstdc++-v3/doc/html/manual/bk01pt11ch28s02.html +++ /dev/null @@ -1,49 +0,0 @@ -<?xml version="1.0" encoding="UTF-8" standalone="no"?> -<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> -<html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>Performance</title><meta name="generator" content="DocBook XSL Stylesheets V1.74.0" /><meta name="keywords" content=" ISO C++ , library " /><link rel="home" href="../spine.html" title="The GNU C++ Library Documentation" /><link rel="up" href="io_and_c.html" title="Chapter 28. Interacting with C" /><link rel="prev" href="io_and_c.html" title="Chapter 28. Interacting with C" /><link rel="next" href="extensions.html" title="Part XII. Extensions" /></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Performance</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="io_and_c.html">Prev</a> </td><th width="60%" align="center">Chapter 28. Interacting with C</th><td width="20%" align="right"> <a accesskey="n" href="extensions.html">Next</a></td></tr></table><hr /></div><div class="sect1" lang="en" xml:lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="manual.io.c.sync"></a>Performance</h2></div></div></div><p> - Pathetic Performance? Ditch C. - </p><p>It sounds like a flame on C, but it isn't. Really. Calm down. - I'm just saying it to get your attention. - </p><p>Because the C++ library includes the C library, both C-style and - C++-style I/O have to work at the same time. For example: - </p><pre class="programlisting"> - #include <iostream> - #include <cstdio> - - std::cout << "Hel"; - std::printf ("lo, worl"); - std::cout << "d!\n"; - </pre><p>This must do what you think it does. - </p><p>Alert members of the audience will immediately notice that buffering - is going to make a hash of the output unless special steps are taken. - </p><p>The special steps taken by libstdc++, at least for version 3.0, - involve doing very little buffering for the standard streams, leaving - most of the buffering to the underlying C library. (This kind of - thing is tricky to get right.) - The upside is that correctness is ensured. The downside is that - writing through <code class="code">cout</code> can quite easily lead to awful - performance when the C++ I/O library is layered on top of the C I/O - library (as it is for 3.0 by default). Some patches have been applied - which improve the situation for 3.1. - </p><p>However, the C and C++ standard streams only need to be kept in sync - when both libraries' facilities are in use. If your program only uses - C++ I/O, then there's no need to sync with the C streams. The right - thing to do in this case is to call - </p><pre class="programlisting"> - #include <span class="emphasis"><em>any of the I/O headers such as ios, iostream, etc</em></span> - - std::ios::sync_with_stdio(false); - </pre><p>You must do this before performing any I/O via the C++ stream objects. - Once you call this, the C++ streams will operate independently of the - (unused) C streams. For GCC 3.x, this means that <code class="code">cout</code> and - company will become fully buffered on their own. - </p><p>Note, by the way, that the synchronization requirement only applies to - the standard streams (<code class="code">cin</code>, <code class="code">cout</code>, - <code class="code">cerr</code>, - <code class="code">clog</code>, and their wide-character counterparts). File stream - objects that you declare yourself have no such requirement and are fully - buffered. - </p></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="io_and_c.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="io_and_c.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="extensions.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Chapter 28. Interacting with C </td><td width="20%" align="center"><a accesskey="h" href="../spine.html">Home</a></td><td width="40%" align="right" valign="top"> Part XII. - Extensions - -</td></tr></table></div></body></html> |