libstdc++-v3/doc/html/manual/debug_mode.html

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  17     "><link rel="home" href="../index.html" title="The GNU C++ Library"><link rel="up" href="extensions.html" title="Part III.  Extensions"><link rel="prev" href="ext_compile_checks.html" title="Chapter 16. Compile Time Checks"><link rel="next" href="bk01pt03ch17s02.html" title="Semantics"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Chapter 17. Debug Mode</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="ext_compile_checks.html">Prev</a> </td><th width="60%" align="center">Part III.
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  20 </th><td width="20%" align="right"> <a accesskey="n" href="bk01pt03ch17s02.html">Next</a></td></tr></table><hr></div><div class="chapter" title="Chapter 17. Debug Mode"><div class="titlepage"><div><div><h2 class="title"><a name="manual.ext.debug_mode"></a>Chapter 17. Debug Mode</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="debug_mode.html#manual.ext.debug_mode.intro">Intro</a></span></dt><dt><span class="section"><a href="bk01pt03ch17s02.html">Semantics</a></span></dt><dt><span class="section"><a href="bk01pt03ch17s03.html">Using</a></span></dt><dd><dl><dt><span class="section"><a href="bk01pt03ch17s03.html#debug_mode.using.mode">Using the Debug Mode</a></span></dt><dt><span class="section"><a href="bk01pt03ch17s03.html#debug_mode.using.specific">Using a Specific Debug Container</a></span></dt></dl></dd><dt><span class="section"><a href="bk01pt03ch17s04.html">Design</a></span></dt><dd><dl><dt><span class="section"><a href="bk01pt03ch17s04.html#debug_mode.design.goals">Goals</a></span></dt><dt><span class="section"><a href="bk01pt03ch17s04.html#debug_mode.design.methods">Methods</a></span></dt><dd><dl><dt><span class="section"><a href="bk01pt03ch17s04.html#debug_mode.design.methods.wrappers">The Wrapper Model</a></span></dt><dd><dl><dt><span class="section"><a href="bk01pt03ch17s04.html#debug_mode.design.methods.safe_iter">Safe Iterators</a></span></dt><dt><span class="section"><a href="bk01pt03ch17s04.html#debug_mode.design.methods.safe_seq">Safe Sequences (Containers)</a></span></dt></dl></dd><dt><span class="section"><a href="bk01pt03ch17s04.html#debug_mode.design.methods.precond">Precondition Checking</a></span></dt><dt><span class="section"><a href="bk01pt03ch17s04.html#debug_mode.design.methods.coexistence">Release- and debug-mode coexistence</a></span></dt><dd><dl><dt><span class="section"><a href="bk01pt03ch17s04.html#methods.coexistence.compile">Compile-time coexistence of release- and debug-mode components</a></span></dt><dt><span class="section"><a href="bk01pt03ch17s04.html#methods.coexistence.link">Link- and run-time coexistence of release- and
  21     debug-mode components</a></span></dt><dt><span class="section"><a href="bk01pt03ch17s04.html#methods.coexistence.alt">Alternatives for Coexistence</a></span></dt></dl></dd></dl></dd><dt><span class="section"><a href="bk01pt03ch17s04.html#debug_mode.design.other">Other Implementations</a></span></dt></dl></dd></dl></div><div class="section" title="Intro"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="manual.ext.debug_mode.intro"></a>Intro</h2></div></div></div><p>
  22     By default, libstdc++ is built with efficiency in mind, and
  23     therefore performs little or no error checking that is not
  24     required by the C++ standard. This means that programs that
  25     incorrectly use the C++ standard library will exhibit behavior
  26     that is not portable and may not even be predictable, because they
  27     tread into implementation-specific or undefined behavior. To
  28     detect some of these errors before they can become problematic,
  29     libstdc++ offers a debug mode that provides additional checking of
  30     library facilities, and will report errors in the use of libstdc++
  31     as soon as they can be detected by emitting a description of the
  32     problem to standard error and aborting the program.  This debug
  33     mode is available with GCC 3.4.0 and later versions.
  34   </p><p>
  35     The libstdc++ debug mode performs checking for many areas of the
  36     C++ standard, but the focus is on checking interactions among
  37     standard iterators, containers, and algorithms, including:
  38   </p><div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem"><p><span class="emphasis"><em>Safe iterators</em></span>: Iterators keep track of the
  39     container whose elements they reference, so errors such as
  40     incrementing a past-the-end iterator or dereferencing an iterator
  41     that points to a container that has been destructed are diagnosed
  42     immediately.</p></li><li class="listitem"><p><span class="emphasis"><em>Algorithm preconditions</em></span>: Algorithms attempt to
  43     validate their input parameters to detect errors as early as
  44     possible. For instance, the <code class="code">set_intersection</code>
  45     algorithm requires that its iterator
  46     parameters <code class="code">first1</code> and <code class="code">last1</code> form a valid
  47     iterator range, and that the sequence
  48     [<code class="code">first1</code>, <code class="code">last1</code>) is sorted according to
  49     the same predicate that was passed
  50     to <code class="code">set_intersection</code>; the libstdc++ debug mode will
  51     detect an error if the sequence is not sorted or was sorted by a
  52     different predicate.</p></li></ul></div></div></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="ext_compile_checks.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="extensions.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="bk01pt03ch17s02.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Chapter 16. Compile Time Checks </td><td width="20%" align="center"><a accesskey="h" href="../index.html">Home</a></td><td width="40%" align="right" valign="top"> Semantics</td></tr></table></div></body></html>