136ac495dSmrg<?xml version="1.0" encoding="UTF-8" standalone="no"?> 236ac495dSmrg<!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>Headers</title><meta name="generator" content="DocBook XSL Stylesheets Vsnapshot" /><meta name="keywords" content="ISO C++, library" /><meta name="keywords" content="ISO C++, runtime, library" /><link rel="home" href="../index.html" title="The GNU C++ Library" /><link rel="up" href="using.html" title="Chapter 3. Using" /><link rel="prev" href="using.html" title="Chapter 3. Using" /><link rel="next" href="using_macros.html" title="Macros" /></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Headers</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="using.html">Prev</a> </td><th width="60%" align="center">Chapter 3. Using</th><td width="20%" align="right"> <a accesskey="n" href="using_macros.html">Next</a></td></tr></table><hr /></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="manual.intro.using.headers"></a>Headers</h2></div></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="manual.intro.using.headers.all"></a>Header Files</h3></div></div></div><p> 336ac495dSmrg The C++ standard specifies the entire set of header files that 436ac495dSmrg must be available to all hosted implementations. Actually, the 536ac495dSmrg word "files" is a misnomer, since the contents of the 636ac495dSmrg headers don't necessarily have to be in any kind of external 736ac495dSmrg file. The only rule is that when one <code class="code">#include</code>s a 836ac495dSmrg header, the contents of that header become available, no matter 936ac495dSmrg how. 1036ac495dSmrg </p><p> 1136ac495dSmrg That said, in practice files are used. 1236ac495dSmrg </p><p> 1336ac495dSmrg There are two main types of include files: header files related 1436ac495dSmrg to a specific version of the ISO C++ standard (called Standard 1536ac495dSmrg Headers), and all others (TS, TR1, C++ ABI, and Extensions). 1636ac495dSmrg </p><p> 1736ac495dSmrg Multiple dialects of standard headers are supported, corresponding to 1836ac495dSmrg the 1998 standard as updated for 2003, the 2011 standard, the 2014 1936ac495dSmrg standard, and so on. 2036ac495dSmrg </p><p> 2136ac495dSmrg <a class="xref" href="using_headers.html#table.cxx98_headers" title="Table 3.2. C++ 1998 Library Headers">Table 3.2, “C++ 1998 Library Headers”</a> and 2236ac495dSmrg <a class="xref" href="using_headers.html#table.cxx98_cheaders" title="Table 3.3. C++ 1998 Library Headers for C Library Facilities">Table 3.3, “C++ 1998 Library Headers for C Library Facilities”</a> and 2336ac495dSmrg <a class="xref" href="using_headers.html#table.cxx98_deprheaders" title="Table 3.4. C++ 1998 Deprecated Library Header">Table 3.4, “C++ 1998 Deprecated Library Header”</a> 2436ac495dSmrg show the C++98/03 include files. 2536ac495dSmrg These are available in the C++98 compilation mode, 2636ac495dSmrg i.e. <code class="code">-std=c++98</code> or <code class="code">-std=gnu++98</code>. 2736ac495dSmrg Unless specified otherwise below, they are also available in later modes 2836ac495dSmrg (C++11, C++14 etc). 2936ac495dSmrg </p><div class="table"><a id="table.cxx98_headers"></a><p class="title"><strong>Table 3.2. C++ 1998 Library Headers</strong></p><div class="table-contents"><table class="table" summary="C++ 1998 Library Headers" border="1"><colgroup><col align="left" class="c1" /><col align="left" class="c2" /><col align="left" class="c3" /><col align="left" class="c4" /><col align="left" class="c5" /></colgroup><tbody><tr><td align="left"><code class="filename">algorithm</code></td><td align="left"><code class="filename">bitset</code></td><td align="left"><code class="filename">complex</code></td><td align="left"><code class="filename">deque</code></td><td align="left"><code class="filename">exception</code></td></tr><tr><td align="left"><code class="filename">fstream</code></td><td align="left"><code class="filename">functional</code></td><td align="left"><code class="filename">iomanip</code></td><td align="left"><code class="filename">ios</code></td><td align="left"><code class="filename">iosfwd</code></td></tr><tr><td align="left"><code class="filename">iostream</code></td><td align="left"><code class="filename">istream</code></td><td align="left"><code class="filename">iterator</code></td><td align="left"><code class="filename">limits</code></td><td align="left"><code class="filename">list</code></td></tr><tr><td align="left"><code class="filename">locale</code></td><td align="left"><code class="filename">map</code></td><td align="left"><code class="filename">memory</code></td><td align="left"><code class="filename">new</code></td><td align="left"><code class="filename">numeric</code></td></tr><tr><td align="left"><code class="filename">ostream</code></td><td align="left"><code class="filename">queue</code></td><td align="left"><code class="filename">set</code></td><td align="left"><code class="filename">sstream</code></td><td align="left"><code class="filename">stack</code></td></tr><tr><td align="left"><code class="filename">stdexcept</code></td><td align="left"><code class="filename">streambuf</code></td><td align="left"><code class="filename">string</code></td><td align="left"><code class="filename">utility</code></td><td align="left"><code class="filename">typeinfo</code></td></tr><tr><td align="left"><code class="filename">valarray</code></td><td align="left"><code class="filename">vector</code></td><td colspan="3" align="left"> </td></tr></tbody></table></div></div><br class="table-break" /><p></p><div class="table"><a id="table.cxx98_cheaders"></a><p class="title"><strong>Table 3.3. C++ 1998 Library Headers for C Library Facilities</strong></p><div class="table-contents"><table class="table" summary="C++ 1998 Library Headers for C Library Facilities" border="1"><colgroup><col align="left" class="c1" /><col align="left" class="c2" /><col align="left" class="c3" /><col align="left" class="c4" /><col align="left" class="c5" /></colgroup><tbody><tr><td align="left"><code class="filename">cassert</code></td><td align="left"><code class="filename">cerrno</code></td><td align="left"><code class="filename">cctype</code></td><td align="left"><code class="filename">cfloat</code></td><td align="left"><code class="filename">ciso646</code></td></tr><tr><td align="left"><code class="filename">climits</code></td><td align="left"><code class="filename">clocale</code></td><td align="left"><code class="filename">cmath</code></td><td align="left"><code class="filename">csetjmp</code></td><td align="left"><code class="filename">csignal</code></td></tr><tr><td align="left"><code class="filename">cstdarg</code></td><td align="left"><code class="filename">cstddef</code></td><td align="left"><code class="filename">cstdio</code></td><td align="left"><code class="filename">cstdlib</code></td><td align="left"><code class="filename">cstring</code></td></tr><tr><td align="left"><code class="filename">ctime</code></td><td align="left"><code class="filename">cwchar</code></td><td align="left"><code class="filename">cwctype</code></td><td colspan="2" align="left"> </td></tr></tbody></table></div></div><br class="table-break" /><p> 3036ac495dSmrg The following header is deprecated 3136ac495dSmrg and might be removed from a future C++ standard. 3236ac495dSmrg</p><div class="table"><a id="table.cxx98_deprheaders"></a><p class="title"><strong>Table 3.4. C++ 1998 Deprecated Library Header</strong></p><div class="table-contents"><table class="table" summary="C++ 1998 Deprecated Library Header" border="1"><colgroup><col align="left" class="c1" /></colgroup><tbody><tr><td align="left"><code class="filename">strstream</code></td></tr></tbody></table></div></div><br class="table-break" /><p> 3336ac495dSmrg<a class="xref" href="using_headers.html#table.cxx11_headers" title="Table 3.5. C++ 2011 Library Headers">Table 3.5, “C++ 2011 Library Headers”</a> and 3436ac495dSmrg<a class="xref" href="using_headers.html#table.cxx11_cheaders" title="Table 3.6. C++ 2011 Library Headers for C Library Facilities">Table 3.6, “C++ 2011 Library Headers for C Library Facilities”</a> show the C++11 include files. 3536ac495dSmrgThese are available in C++11 compilation 3636ac495dSmrgmode, i.e. <code class="literal">-std=c++11</code> or <code class="literal">-std=gnu++11</code>. 3736ac495dSmrgIncluding these headers in C++98/03 mode may result in compilation errors. 3836ac495dSmrgUnless specified otherwise below, they are also available in later modes 3936ac495dSmrg(C++14 etc). 4036ac495dSmrg</p><p></p><div class="table"><a id="table.cxx11_headers"></a><p class="title"><strong>Table 3.5. C++ 2011 Library Headers</strong></p><div class="table-contents"><table class="table" summary="C++ 2011 Library Headers" border="1"><colgroup><col align="left" class="c1" /><col align="left" class="c2" /><col align="left" class="c3" /><col align="left" class="c4" /><col align="left" class="c5" /></colgroup><tbody><tr><td align="left"><code class="filename">array</code></td><td align="left"><code class="filename">atomic</code></td><td align="left"><code class="filename">chrono</code></td><td align="left"><code class="filename">codecvt</code></td><td align="left"><code class="filename">condition_variable</code></td></tr><tr><td align="left"><code class="filename">forward_list</code></td><td align="left"><code class="filename">future</code></td><td align="left"><code class="filename">initalizer_list</code></td><td align="left"><code class="filename">mutex</code></td><td align="left"><code class="filename">random</code></td></tr><tr><td align="left"><code class="filename">ratio</code></td><td align="left"><code class="filename">regex</code></td><td align="left"><code class="filename">scoped_allocator</code></td><td align="left"><code class="filename">system_error</code></td><td align="left"><code class="filename">thread</code></td></tr><tr><td align="left"><code class="filename">tuple</code></td><td align="left"><code class="filename">typeindex</code></td><td align="left"><code class="filename">type_traits</code></td><td align="left"><code class="filename">unordered_map</code></td><td align="left"><code class="filename">unordered_set</code></td></tr></tbody></table></div></div><br class="table-break" /><p></p><div class="table"><a id="table.cxx11_cheaders"></a><p class="title"><strong>Table 3.6. C++ 2011 Library Headers for C Library Facilities</strong></p><div class="table-contents"><table class="table" summary="C++ 2011 Library Headers for C Library Facilities" border="1"><colgroup><col align="left" class="c1" /><col align="left" class="c2" /><col align="left" class="c3" /><col align="left" class="c4" /><col align="left" class="c5" /></colgroup><tbody><tr><td align="left"><code class="filename">ccomplex</code></td><td align="left"><code class="filename">cfenv</code></td><td align="left"><code class="filename">cinttypes</code></td><td align="left"><code class="filename">cstdalign</code></td><td align="left"><code class="filename">cstdbool</code></td></tr><tr><td align="left"><code class="filename">cstdint</code></td><td align="left"><code class="filename">ctgmath</code></td><td align="left"><code class="filename">cuchar</code></td><td colspan="2" align="left"> </td></tr></tbody></table></div></div><br class="table-break" /><p> 4136ac495dSmrg<a class="xref" href="using_headers.html#table.cxx14_headers" title="Table 3.7. C++ 2014 Library Header">Table 3.7, “C++ 2014 Library Header”</a> shows the C++14 include file. 4236ac495dSmrgThis is available in C++14 compilation 4336ac495dSmrgmode, i.e. <code class="literal">-std=c++14</code> or <code class="literal">-std=gnu++14</code>. 4436ac495dSmrgIncluding this header in C++98/03 mode or C++11 will not result in 4536ac495dSmrgcompilation errors, but will not define anything. 4636ac495dSmrgUnless specified otherwise below, it is also available in later modes 4736ac495dSmrg(C++17 etc). 4836ac495dSmrg</p><p></p><div class="table"><a id="table.cxx14_headers"></a><p class="title"><strong>Table 3.7. C++ 2014 Library Header</strong></p><div class="table-contents"><table class="table" summary="C++ 2014 Library Header" border="1"><colgroup><col align="left" class="c1" /></colgroup><tbody><tr><td align="left"><code class="filename">shared_mutex</code></td></tr></tbody></table></div></div><br class="table-break" /><p> 4936ac495dSmrg<a class="xref" href="using_headers.html#table.cxx17_headers" title="Table 3.8. C++ 2017 Library Headers">Table 3.8, “C++ 2017 Library Headers”</a> shows the C++17 include files. 5036ac495dSmrgThese are available in C++17 compilation 5136ac495dSmrgmode, i.e. <code class="literal">-std=c++17</code> or <code class="literal">-std=gnu++17</code>. 5236ac495dSmrgIncluding these headers in earlier modes will not result in 5336ac495dSmrgcompilation errors, but will not define anything. 5436ac495dSmrgUnless specified otherwise below, they are also available in later modes 5536ac495dSmrg(C++20 etc). 56c0a68be4Smrg</p><p></p><div class="table"><a id="table.cxx17_headers"></a><p class="title"><strong>Table 3.8. C++ 2017 Library Headers</strong></p><div class="table-contents"><table class="table" summary="C++ 2017 Library Headers" border="1"><colgroup><col align="left" class="c1" /><col align="left" class="c2" /><col align="left" class="c3" /><col align="left" class="c4" /><col align="left" class="c5" /></colgroup><tbody><tr><td align="left"><code class="filename">any</code></td><td align="left"><code class="filename">charconv</code></td><td align="left"><code class="filename">execution</code></td><td align="left"><code class="filename">filesystem</code></td><td align="left"><code class="filename">memory_resource</code></td></tr><tr><td align="left"><code class="filename">optional</code></td><td align="left"><code class="filename">string_view</code></td><td align="left"><code class="filename">variant</code></td><td colspan="2" align="left"> </td></tr></tbody></table></div></div><br class="table-break" /><p> 57c0a68be4Smrg<a class="xref" href="using_headers.html#table.cxx20_headers" title="Table 3.9. C++ 2020 Library Headers">Table 3.9, “C++ 2020 Library Headers”</a> 58c0a68be4Smrgshows the C++2a include files. 59c0a68be4SmrgThese are available in C++2a compilation 60c0a68be4Smrgmode, i.e. <code class="literal">-std=c++2a</code> or <code class="literal">-std=gnu++2a</code>. 61c0a68be4SmrgIncluding these headers in earlier modes will not result in 62c0a68be4Smrgcompilation errors, but will not define anything. 63c0a68be4Smrg 64c0a68be4Smrg</p><p></p><div class="table"><a id="table.cxx20_headers"></a><p class="title"><strong>Table 3.9. C++ 2020 Library Headers</strong></p><div class="table-contents"><table class="table" summary="C++ 2020 Library Headers" border="1"><colgroup><col align="left" class="c1" /><col align="left" class="c2" /></colgroup><tbody><tr><td align="left"><code class="filename">bit</code></td><td align="left"><code class="filename">version</code></td></tr></tbody></table></div></div><br class="table-break" /><p> 65c0a68be4Smrg The following headers have been removed in the C++2a working draft. 66c0a68be4Smrg They are still available when using this implementation, but in future 67c0a68be4Smrg they might start to produce warnings or errors when included in C++2a mode. 68c0a68be4Smrg Programs that intend to be portable should not include them. 69c0a68be4Smrg</p><div class="table"><a id="table.cxx20_deprheaders"></a><p class="title"><strong>Table 3.10. C++ 2020 Obsolete Headers</strong></p><div class="table-contents"><table class="table" summary="C++ 2020 Obsolete Headers" border="1"><colgroup><col align="left" class="c1" /><col align="left" class="c2" /><col align="left" class="c3" /><col align="left" class="c4" /><col align="left" class="c5" /></colgroup><tbody><tr><td align="left"><code class="filename">ccomplex</code></td><td align="left"><code class="filename">ciso646</code></td><td align="left"><code class="filename">cstdalign</code></td><td align="left"><code class="filename">cstdbool</code></td><td align="left"><code class="filename">ctgmath</code></td></tr></tbody></table></div></div><br class="table-break" /><p> 70c0a68be4Smrg<a class="xref" href="using_headers.html#table.filesystemts_headers" title="Table 3.11. File System TS Header">Table 3.11, “File System TS Header”</a>, 7136ac495dSmrgshows the additional include file define by the 7236ac495dSmrgFile System Technical Specification, ISO/IEC TS 18822. 7336ac495dSmrgThis is available in C++11 and later compilation modes. 7436ac495dSmrgIncluding this header in earlier modes will not result in 7536ac495dSmrgcompilation errors, but will not define anything. 76c0a68be4Smrg</p><p></p><div class="table"><a id="table.filesystemts_headers"></a><p class="title"><strong>Table 3.11. File System TS Header</strong></p><div class="table-contents"><table class="table" summary="File System TS Header" border="1"><colgroup><col align="left" class="c1" /></colgroup><tbody><tr><td align="left"><code class="filename">experimental/filesystem</code></td></tr></tbody></table></div></div><br class="table-break" /><p> 77c0a68be4Smrg<a class="xref" href="using_headers.html#table.libfundts_headers" title="Table 3.12. Library Fundamentals TS Headers">Table 3.12, “Library Fundamentals TS Headers”</a>, 7836ac495dSmrgshows the additional include files define by the C++ Extensions for 7936ac495dSmrgLibrary Fundamentals Technical Specification, ISO/IEC TS 19568. 8036ac495dSmrgThese are available in C++14 and later compilation modes. 8136ac495dSmrgIncluding these headers in earlier modes will not result in 8236ac495dSmrgcompilation errors, but will not define anything. 83c0a68be4Smrg</p><p></p><div class="table"><a id="table.libfundts_headers"></a><p class="title"><strong>Table 3.12. Library Fundamentals TS Headers</strong></p><div class="table-contents"><table class="table" summary="Library Fundamentals TS Headers" border="1"><colgroup><col align="left" class="c1" /><col align="left" class="c2" /><col align="left" class="c3" /><col align="left" class="c4" /><col align="left" class="c5" /></colgroup><tbody><tr><td align="left"><code class="filename">experimental/algorithm</code></td><td align="left"><code class="filename">experimental/any</code></td><td align="left"><code class="filename">experimental/array</code></td><td align="left"><code class="filename">experimental/chrono</code></td><td align="left"><code class="filename">experimental/deque</code></td></tr><tr><td align="left"><code class="filename">experimental/forward_list</code></td><td align="left"><code class="filename">experimental/functional</code></td><td align="left"><code class="filename">experimental/iterator</code></td><td align="left"><code class="filename">experimental/list</code></td><td align="left"><code class="filename">experimental/map</code></td></tr><tr><td align="left"><code class="filename">experimental/memory</code></td><td align="left"><code class="filename">experimental/memory_resource</code></td><td align="left"><code class="filename">experimental/numeric</code></td><td align="left"><code class="filename">experimental/optional</code></td><td align="left"><code class="filename">experimental/propagate_const</code></td></tr><tr><td align="left"><code class="filename">experimental/random</code></td><td align="left"><code class="filename">experimental/ratio</code></td><td align="left"><code class="filename">experimental/regex</code></td><td align="left"><code class="filename">experimental/set</code></td><td align="left"><code class="filename">experimental/source_location</code></td></tr><tr><td align="left"><code class="filename">experimental/string</code></td><td align="left"><code class="filename">experimental/string_view</code></td><td align="left"><code class="filename">experimental/system_error</code></td><td align="left"><code class="filename">experimental/tuple</code></td><td align="left"><code class="filename">experimental/type_traits</code></td></tr><tr><td align="left"><code class="filename">experimental/unordered_map</code></td><td align="left"><code class="filename">experimental/unordered_set</code></td><td align="left"><code class="filename">experimental/utility</code></td><td align="left"><code class="filename">experimental/vector</code></td><td align="left"> </td></tr></tbody></table></div></div><br class="table-break" /><p> 8436ac495dSmrg In addition, TR1 includes as: 85c0a68be4Smrg</p><div class="table"><a id="table.tr1_headers"></a><p class="title"><strong>Table 3.13. C++ TR 1 Library Headers</strong></p><div class="table-contents"><table class="table" summary="C++ TR 1 Library Headers" border="1"><colgroup><col align="left" class="c1" /><col align="left" class="c2" /><col align="left" class="c3" /><col align="left" class="c4" /><col align="left" class="c5" /></colgroup><tbody><tr><td align="left"><code class="filename">tr1/array</code></td><td align="left"><code class="filename">tr1/complex</code></td><td align="left"><code class="filename">tr1/memory</code></td><td align="left"><code class="filename">tr1/functional</code></td><td align="left"><code class="filename">tr1/random</code></td></tr><tr><td align="left"><code class="filename">tr1/regex</code></td><td align="left"><code class="filename">tr1/tuple</code></td><td align="left"><code class="filename">tr1/type_traits</code></td><td align="left"><code class="filename">tr1/unordered_map</code></td><td align="left"><code class="filename">tr1/unordered_set</code></td></tr><tr><td align="left"><code class="filename">tr1/utility</code></td><td colspan="4" align="left"> </td></tr></tbody></table></div></div><br class="table-break" /><p></p><div class="table"><a id="table.tr1_cheaders"></a><p class="title"><strong>Table 3.14. C++ TR 1 Library Headers for C Library Facilities</strong></p><div class="table-contents"><table class="table" summary="C++ TR 1 Library Headers for C Library Facilities" border="1"><colgroup><col align="left" class="c1" /><col align="left" class="c2" /><col align="left" class="c3" /><col align="left" class="c4" /><col align="left" class="c5" /></colgroup><tbody><tr><td align="left"><code class="filename">tr1/ccomplex</code></td><td align="left"><code class="filename">tr1/cfenv</code></td><td align="left"><code class="filename">tr1/cfloat</code></td><td align="left"><code class="filename">tr1/cmath</code></td><td align="left"><code class="filename">tr1/cinttypes</code></td></tr><tr><td align="left"><code class="filename">tr1/climits</code></td><td align="left"><code class="filename">tr1/cstdarg</code></td><td align="left"><code class="filename">tr1/cstdbool</code></td><td align="left"><code class="filename">tr1/cstdint</code></td><td align="left"><code class="filename">tr1/cstdio</code></td></tr><tr><td align="left"><code class="filename">tr1/cstdlib</code></td><td align="left"><code class="filename">tr1/ctgmath</code></td><td align="left"><code class="filename">tr1/ctime</code></td><td align="left"><code class="filename">tr1/cwchar</code></td><td align="left"><code class="filename">tr1/cwctype</code></td></tr></tbody></table></div></div><br class="table-break" /><p>Decimal floating-point arithmetic is available if the C++ 8636ac495dSmrgcompiler supports scalar decimal floating-point types defined via 8736ac495dSmrg<code class="code">__attribute__((mode(SD|DD|LD)))</code>. 88c0a68be4Smrg</p><div class="table"><a id="table.decfp_headers"></a><p class="title"><strong>Table 3.15. C++ TR 24733 Decimal Floating-Point Header</strong></p><div class="table-contents"><table class="table" summary="C++ TR 24733 Decimal Floating-Point Header" border="1"><colgroup><col align="left" class="c1" /></colgroup><tbody><tr><td align="left"><code class="filename">decimal/decimal</code></td></tr></tbody></table></div></div><br class="table-break" /><p> 8936ac495dSmrg Also included are files for the C++ ABI interface: 90c0a68be4Smrg</p><div class="table"><a id="table.abi_headers"></a><p class="title"><strong>Table 3.16. C++ ABI Headers</strong></p><div class="table-contents"><table class="table" summary="C++ ABI Headers" border="1"><colgroup><col align="left" class="c1" /><col align="left" class="c2" /></colgroup><tbody><tr><td align="left"><code class="filename">cxxabi.h</code></td><td align="left"><code class="filename">cxxabi_forced.h</code></td></tr></tbody></table></div></div><br class="table-break" /><p> 9136ac495dSmrg And a large variety of extensions. 92*8feb0f0bSmrg</p><div class="table"><a id="table.ext_headers"></a><p class="title"><strong>Table 3.17. Extension Headers</strong></p><div class="table-contents"><table class="table" summary="Extension Headers" border="1"><colgroup><col align="left" class="c1" /><col align="left" class="c2" /><col align="left" class="c3" /><col align="left" class="c4" /><col align="left" class="c5" /></colgroup><tbody><tr><td align="left"><code class="filename">ext/algorithm</code></td><td align="left"><code class="filename">ext/atomicity.h</code></td><td align="left"><code class="filename">ext/bitmap_allocator.h</code></td><td align="left"><code class="filename">ext/cast.h</code></td><td class="auto-generated"> </td></tr><tr><td align="left"><code class="filename">ext/codecvt_specializations.h</code></td><td align="left"><code class="filename">ext/concurrence.h</code></td><td align="left"><code class="filename">ext/debug_allocator.h</code></td><td align="left"><code class="filename">ext/enc_filebuf.h</code></td><td align="left"><code class="filename">ext/extptr_allocator.h</code></td></tr><tr><td align="left"><code class="filename">ext/functional</code></td><td align="left"><code class="filename">ext/iterator</code></td><td align="left"><code class="filename">ext/malloc_allocator.h</code></td><td align="left"><code class="filename">ext/memory</code></td><td align="left"><code class="filename">ext/mt_allocator.h</code></td></tr><tr><td align="left"><code class="filename">ext/new_allocator.h</code></td><td align="left"><code class="filename">ext/numeric</code></td><td align="left"><code class="filename">ext/numeric_traits.h</code></td><td align="left"><code class="filename">ext/pb_ds/assoc_container.h</code></td><td align="left"><code class="filename">ext/pb_ds/priority_queue.h</code></td></tr><tr><td align="left"><code class="filename">ext/pod_char_traits.h</code></td><td align="left"><code class="filename">ext/pool_allocator.h</code></td><td align="left"><code class="filename">ext/rb_tree</code></td><td align="left"><code class="filename">ext/rope</code></td><td align="left"><code class="filename">ext/slist</code></td></tr><tr><td align="left"><code class="filename">ext/stdio_filebuf.h</code></td><td align="left"><code class="filename">ext/stdio_sync_filebuf.h</code></td><td align="left"><code class="filename">ext/throw_allocator.h</code></td><td align="left"><code class="filename">ext/typelist.h</code></td><td align="left"><code class="filename">ext/type_traits.h</code></td></tr><tr><td align="left"><code class="filename">ext/vstring.h</code></td><td colspan="4" align="left"> </td></tr></tbody></table></div></div><br class="table-break" /><p></p><div class="table"><a id="table.debug_headers"></a><p class="title"><strong>Table 3.18. Extension Debug Headers</strong></p><div class="table-contents"><table class="table" summary="Extension Debug Headers" border="1"><colgroup><col align="left" class="c1" /><col align="left" class="c2" /><col align="left" class="c3" /><col align="left" class="c4" /><col align="left" class="c5" /></colgroup><tbody><tr><td align="left"><code class="filename">debug/array</code></td><td align="left"><code class="filename">debug/bitset</code></td><td align="left"><code class="filename">debug/deque</code></td><td align="left"><code class="filename">debug/forward_list</code></td><td align="left"><code class="filename">debug/list</code></td></tr><tr><td align="left"><code class="filename">debug/map</code></td><td align="left"><code class="filename">debug/set</code></td><td align="left"><code class="filename">debug/string</code></td><td align="left"><code class="filename">debug/unordered_map</code></td><td align="left"><code class="filename">debug/unordered_set</code></td></tr><tr><td align="left"><code class="filename">debug/vector</code></td><td colspan="4" align="left"> </td></tr></tbody></table></div></div><br class="table-break" /><p></p><div class="table"><a id="table.parallel_headers"></a><p class="title"><strong>Table 3.19. Extension Parallel Headers</strong></p><div class="table-contents"><table class="table" summary="Extension Parallel Headers" border="1"><colgroup><col align="left" class="c1" /><col align="left" class="c2" /></colgroup><tbody><tr><td align="left"><code class="filename">parallel/algorithm</code></td><td align="left"><code class="filename">parallel/numeric</code></td></tr></tbody></table></div></div><br class="table-break" /></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="manual.intro.using.headers.mixing"></a>Mixing Headers</h3></div></div></div><p> A few simple rules. 9336ac495dSmrg</p><p>First, mixing different dialects of the standard headers is not 9436ac495dSmrgpossible. It's an all-or-nothing affair. Thus, code like 9536ac495dSmrg</p><pre class="programlisting"> 9636ac495dSmrg#include <array> 9736ac495dSmrg#include <functional> 9836ac495dSmrg</pre><p>Implies C++11 mode. To use the entities in <array>, the C++11 9936ac495dSmrgcompilation mode must be used, which implies the C++11 functionality 10036ac495dSmrg(and deprecations) in <functional> will be present. 10136ac495dSmrg</p><p>Second, the other headers can be included with either dialect of 10236ac495dSmrgthe standard headers, although features and types specific to C++11 10336ac495dSmrgare still only enabled when in C++11 compilation mode. So, to use 10436ac495dSmrgrvalue references with <code class="code">__gnu_cxx::vstring</code>, or to use the 10536ac495dSmrgdebug-mode versions of <code class="code">std::unordered_map</code>, one must use 10636ac495dSmrgthe <code class="code">std=gnu++11</code> compiler flag. (Or <code class="code">std=c++11</code>, of course.) 10736ac495dSmrg</p><p>A special case of the second rule is the mixing of TR1 and C++11 10836ac495dSmrgfacilities. It is possible (although not especially prudent) to 10936ac495dSmrginclude both the TR1 version and the C++11 version of header in the 11036ac495dSmrgsame translation unit: 11136ac495dSmrg</p><pre class="programlisting"> 11236ac495dSmrg#include <tr1/type_traits> 11336ac495dSmrg#include <type_traits> 11436ac495dSmrg</pre><p> Several parts of C++11 diverge quite substantially from TR1 predecessors. 11536ac495dSmrg</p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="manual.intro.using.headers.cheaders"></a>The C Headers and <code class="code">namespace std</code></h3></div></div></div><p> 11636ac495dSmrg The standard specifies that if one includes the C-style header 11736ac495dSmrg (<math.h> in this case), the symbols will be available 11836ac495dSmrg in the global namespace and perhaps in 11936ac495dSmrg namespace <code class="code">std::</code> (but this is no longer a firm 12036ac495dSmrg requirement.) On the other hand, including the C++-style 12136ac495dSmrg header (<cmath>) guarantees that the entities will be 12236ac495dSmrg found in namespace std and perhaps in the global namespace. 12336ac495dSmrg </p><p> 12436ac495dSmrgUsage of C++-style headers is recommended, as then 12536ac495dSmrgC-linkage names can be disambiguated by explicit qualification, such 12636ac495dSmrgas by <code class="code">std::abort</code>. In addition, the C++-style headers can 12736ac495dSmrguse function overloading to provide a simpler interface to certain 12836ac495dSmrgfamilies of C-functions. For instance in <cmath>, the 12936ac495dSmrgfunction <code class="code">std::sin</code> has overloads for all the builtin 13036ac495dSmrgfloating-point types. This means that <code class="code">std::sin</code> can be 13136ac495dSmrgused uniformly, instead of a combination 13236ac495dSmrgof <code class="code">std::sinf</code>, <code class="code">std::sin</code>, 13336ac495dSmrgand <code class="code">std::sinl</code>. 13436ac495dSmrg</p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="manual.intro.using.headers.pre"></a>Precompiled Headers</h3></div></div></div><p>There are three base header files that are provided. They can be 13536ac495dSmrgused to precompile the standard headers and extensions into binary 13636ac495dSmrgfiles that may then be used to speed up compilations that use these headers. 13736ac495dSmrg</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>stdc++.h</p><p>Includes all standard headers. Actual content varies depending on 13836ac495dSmrg<a class="link" href="using.html#manual.intro.using.flags" title="Command Options">language dialect</a>. 13936ac495dSmrg</p></li><li class="listitem"><p>stdtr1c++.h</p><p>Includes all of <stdc++.h>, and adds all the TR1 headers. 14036ac495dSmrg</p></li><li class="listitem"><p>extc++.h</p><p>Includes all of <stdc++.h>, and adds all the Extension headers 14136ac495dSmrg(and in C++98 mode also adds all the TR1 headers by including all of 14236ac495dSmrg<stdtr1c++.h>). 14336ac495dSmrg</p></li></ul></div><p>To construct a .gch file from one of these base header files, 14436ac495dSmrgfirst find the include directory for the compiler. One way to do 14536ac495dSmrgthis is:</p><pre class="programlisting"> 14636ac495dSmrgg++ -v hello.cc 14736ac495dSmrg 14836ac495dSmrg#include <...> search starts here: 14936ac495dSmrg /mnt/share/bld/H-x86-gcc.20071201/include/c++/4.3.0 15036ac495dSmrg... 15136ac495dSmrgEnd of search list. 15236ac495dSmrg</pre><p>Then, create a precompiled header file with the same flags that 15336ac495dSmrgwill be used to compile other projects.</p><pre class="programlisting"> 15436ac495dSmrgg++ -Winvalid-pch -x c++-header -g -O2 -o ./stdc++.h.gch /mnt/share/bld/H-x86-gcc.20071201/include/c++/4.3.0/x86_64-unknown-linux-gnu/bits/stdc++.h 15536ac495dSmrg</pre><p>The resulting file will be quite large: the current size is around 15636ac495dSmrgthirty megabytes. </p><p>How to use the resulting file.</p><pre class="programlisting"> 15736ac495dSmrgg++ -I. -include stdc++.h -H -g -O2 hello.cc 15836ac495dSmrg</pre><p>Verification that the PCH file is being used is easy:</p><pre class="programlisting"> 15936ac495dSmrgg++ -Winvalid-pch -I. -include stdc++.h -H -g -O2 hello.cc -o test.exe 16036ac495dSmrg! ./stdc++.h.gch 16136ac495dSmrg. /mnt/share/bld/H-x86-gcc.20071201/include/c++/4.3.0/iostream 16236ac495dSmrg. /mnt/share/bld/H-x86-gcc.20071201include/c++/4.3.0/string 16336ac495dSmrg</pre><p>The exclamation point to the left of the <code class="code">stdc++.h.gch</code> listing means that the generated PCH file was used.</p><p></p><p> Detailed information about creating precompiled header files can be found in the GCC <a class="link" href="http://gcc.gnu.org/onlinedocs/gcc/Precompiled-Headers.html" target="_top">documentation</a>. 16436ac495dSmrg</p></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="using.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="using.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="using_macros.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Chapter 3. 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