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

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   2 <!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>
   3      The C++ standard specifies the entire set of header files that
   4      must be available to all hosted implementations.  Actually, the
   5      word "files" is a misnomer, since the contents of the
   6      headers don't necessarily have to be in any kind of external
   7      file.  The only rule is that when one <code class="code">#include</code>s a
   8      header, the contents of that header become available, no matter
   9      how.
  10    </p><p>
  11    That said, in practice files are used.
  12    </p><p>
  13      There are two main types of include files: header files related
  14      to a specific version of the ISO C++ standard (called Standard
  15      Headers), and all others (TS, TR1, C++ ABI, and Extensions).
  16    </p><p>
  17      Multiple dialects of standard headers are supported, corresponding to
  18      the 1998 standard as updated for 2003, the 2011 standard, the 2014
  19      standard, and so on.
  20    </p><p>
  21      <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
  22      <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
  23      <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>
  24      show the C++98/03 include files.
  25      These are available in the C++98 compilation mode,
  26      i.e. <code class="code">-std=c++98</code> or <code class="code">-std=gnu++98</code>.
  27      Unless specified otherwise below, they are also available in later modes
  28      (C++11, C++14 etc).
  29    </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>
  30   The following header is deprecated
  31   and might be removed from a future C++ standard.
  32 </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>
  33 <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
  34 <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.
  35 These are available in C++11 compilation
  36 mode, i.e. <code class="literal">-std=c++11</code> or <code class="literal">-std=gnu++11</code>.
  37 Including these headers in C++98/03 mode may result in compilation errors.
  38 Unless specified otherwise below, they are also available in later modes
  39 (C++14 etc).
  40 </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>
  41 <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.
  42 This is available in C++14 compilation
  43 mode, i.e. <code class="literal">-std=c++14</code> or <code class="literal">-std=gnu++14</code>.
  44 Including this header in C++98/03 mode or C++11 will not result in
  45 compilation errors, but will not define anything.
  46 Unless specified otherwise below, it is also available in later modes
  47 (C++17 etc).
  48 </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>
  49 <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.
  50 These are available in C++17 compilation
  51 mode, i.e. <code class="literal">-std=c++17</code> or <code class="literal">-std=gnu++17</code>.
  52 Including these headers in earlier modes will not result in
  53 compilation errors, but will not define anything.
  54 Unless specified otherwise below, they are also available in later modes
  55 (C++20 etc).
  56 </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>
  57 <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>
  58 shows the C++2a include files.
  59 These are available in C++2a compilation
  60 mode, i.e. <code class="literal">-std=c++2a</code> or <code class="literal">-std=gnu++2a</code>.
  61 Including these headers in earlier modes will not result in
  62 compilation errors, but will not define anything.
  63
  64 </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>
  65   The following headers have been removed in the C++2a working draft.
  66   They are still available when using this implementation, but in future
  67   they might start to produce warnings or errors when included in C++2a mode.
  68   Programs that intend to be portable should not include them.
  69 </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>
  70 <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>,
  71 shows the additional include file define by the
  72 File System Technical Specification, ISO/IEC TS 18822.
  73 This is available in C++11 and later compilation modes.
  74 Including this header in earlier modes will not result in
  75 compilation errors, but will not define anything.
  76 </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>
  77 <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>,
  78 shows the additional include files define by the C++ Extensions for
  79 Library Fundamentals Technical Specification, ISO/IEC TS 19568.
  80 These are available in C++14 and later compilation modes.
  81 Including these headers in earlier modes will not result in
  82 compilation errors, but will not define anything.
  83 </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 colspan="2" align="left"> </td></tr></tbody></table></div></div><br class="table-break" /><p>
  84   In addition, TR1 includes as:
  85 </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++
  86 compiler supports scalar decimal floating-point types defined via
  87 <code class="code">__attribute__((mode(SD|DD|LD)))</code>.
  88 </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>
  89   Also included are files for the C++ ABI interface:
  90 </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>
  91   And a large variety of extensions.
  92 </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/array_allocator.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></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.profile_headers"></a><p class="title"><strong>Table 3.19. Extension Profile Headers</strong></p><div class="table-contents"><table class="table" summary="Extension Profile Headers" border="1"><colgroup><col align="left" class="c1" /><col align="left" class="c2" /><col align="left" class="c3" /><col align="left" class="c4" /></colgroup><tbody><tr><td align="left"><code class="filename">profile/bitset</code></td><td align="left"><code class="filename">profile/deque</code></td><td align="left"><code class="filename">profile/list</code></td><td align="left"><code class="filename">profile/map</code></td></tr><tr><td align="left"><code class="filename">profile/set</code></td><td align="left"><code class="filename">profile/unordered_map</code></td><td align="left"><code class="filename">profile/unordered_set</code></td><td align="left"><code class="filename">profile/vector</code></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 3.20. 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.
  93 </p><p>First, mixing different dialects of the standard headers is not
  94 possible. It's an all-or-nothing affair. Thus, code like
  95 </p><pre class="programlisting">
  96 #include &lt;array&gt;
  97 #include &lt;functional&gt;
  98 </pre><p>Implies C++11 mode. To use the entities in &lt;array&gt;, the C++11
  99 compilation mode must be used, which implies the C++11 functionality
 100 (and deprecations) in &lt;functional&gt; will be present.
 101 </p><p>Second, the other headers can be included with either dialect of
 102 the standard headers, although features and types specific to C++11
 103 are still only enabled when in C++11 compilation mode. So, to use
 104 rvalue references with <code class="code">__gnu_cxx::vstring</code>, or to use the
 105 debug-mode versions of <code class="code">std::unordered_map</code>, one must use
 106 the <code class="code">std=gnu++11</code> compiler flag. (Or <code class="code">std=c++11</code>, of course.)
 107 </p><p>A special case of the second rule is the mixing of TR1 and C++11
 108 facilities. It is possible (although not especially prudent) to
 109 include both the TR1 version and the C++11 version of header in the
 110 same translation unit:
 111 </p><pre class="programlisting">
 112 #include &lt;tr1/type_traits&gt;
 113 #include &lt;type_traits&gt;
 114 </pre><p> Several parts of C++11 diverge quite substantially from TR1 predecessors.
 115 </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>
 116         The standard specifies that if one includes the C-style header
 117         (&lt;math.h&gt; in this case), the symbols will be available
 118         in the global namespace and perhaps in
 119         namespace <code class="code">std::</code> (but this is no longer a firm
 120         requirement.) On the other hand, including the C++-style
 121         header (&lt;cmath&gt;) guarantees that the entities will be
 122         found in namespace std and perhaps in the global namespace.
 123       </p><p>
 124 Usage of C++-style headers is recommended, as then
 125 C-linkage names can be disambiguated by explicit qualification, such
 126 as by <code class="code">std::abort</code>. In addition, the C++-style headers can
 127 use function overloading to provide a simpler interface to certain
 128 families of C-functions. For instance in &lt;cmath&gt;, the
 129 function <code class="code">std::sin</code> has overloads for all the builtin
 130 floating-point types. This means that <code class="code">std::sin</code> can be
 131 used uniformly, instead of a combination
 132 of <code class="code">std::sinf</code>, <code class="code">std::sin</code>,
 133 and <code class="code">std::sinl</code>.
 134 </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
 135 used to precompile the standard headers and extensions into binary
 136 files that may then be used to speed up compilations that use these headers.
 137 </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
 138 <a class="link" href="using.html#manual.intro.using.flags" title="Command Options">language dialect</a>.
 139 </p></li><li class="listitem"><p>stdtr1c++.h</p><p>Includes all of &lt;stdc++.h&gt;, and adds all the TR1 headers.
 140 </p></li><li class="listitem"><p>extc++.h</p><p>Includes all of &lt;stdc++.h&gt;, and adds all the Extension headers
 141 (and in C++98 mode also adds all the TR1 headers by including all of
 142 &lt;stdtr1c++.h&gt;).
 143 </p></li></ul></div><p>To construct a .gch file from one of these base header files,
 144 first find the include directory for the compiler. One way to do
 145 this is:</p><pre class="programlisting">
 146 g++ -v hello.cc
 147
 148 #include &lt;...&gt; search starts here:
 149  /mnt/share/bld/H-x86-gcc.20071201/include/c++/4.3.0
 150 ...
 151 End of search list.
 152 </pre><p>Then, create a precompiled header file with the same flags that
 153 will be used to compile other projects.</p><pre class="programlisting">
 154 g++ -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
 155 </pre><p>The resulting file will be quite large: the current size is around
 156 thirty megabytes. </p><p>How to use the resulting file.</p><pre class="programlisting">
 157 g++ -I. -include stdc++.h  -H -g -O2 hello.cc
 158 </pre><p>Verification that the PCH file is being used is easy:</p><pre class="programlisting">
 159 g++ -Winvalid-pch -I. -include stdc++.h -H -g -O2 hello.cc -o test.exe
 160 ! ./stdc++.h.gch
 161 . /mnt/share/bld/H-x86-gcc.20071201/include/c++/4.3.0/iostream
 162 . /mnt/share/bld/H-x86-gcc.20071201include/c++/4.3.0/string
 163 </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>.
 164 </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. Using </td><td width="20%" align="center"><a accesskey="h" href="../index.html">Home</a></td><td width="40%" align="right" valign="top"> Macros</td></tr></table></div></body></html>