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

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   3   Porting and Maintenance
   4
   5 </th><td width="20%" align="right"> <a accesskey="n" href="backwards.html">Next</a></td></tr></table><hr /></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="appendix.porting.api"></a>API Evolution and Deprecation History</h2></div></div></div><p>
   6 A list of user-visible changes, in chronological order
   7 </p><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="api.rel_300"></a><code class="constant">3.0</code></h3></div></div></div><p>
   8 Extensions moved to <code class="filename">include/ext</code>.
   9   </p><p>
  10 Include files from the SGI/HP sources that pre-date the ISO standard
  11 are added. These files are placed into
  12 the <code class="filename">include/backward</code> directory and a deprecated warning
  13 is added that notifies on inclusion (<code class="literal">-Wno-deprecated</code>
  14 deactivates the warning.)
  15 </p><p>Deprecated include <code class="filename">&lt;backward/strstream&gt;</code> added.</p><p>Removal of include <code class="filename">&lt;builtinbuf.h&gt;</code>, <code class="filename">&lt;indstream.h&gt;</code>, <code class="filename">&lt;parsestream.h&gt;</code>, <code class="filename">&lt;PlotFile.h&gt;</code>, <code class="filename">&lt;SFile.h&gt;</code>, <code class="filename">&lt;stdiostream.h&gt;</code>, and <code class="filename">&lt;stream.h&gt;</code>.
  16 </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="api.rel_310"></a><code class="constant">3.1</code></h3></div></div></div><p>
  17   </p><p>
  18 Extensions from SGI/HP moved from <code class="code">namespace std</code>
  19 to <code class="code">namespace __gnu_cxx</code>. As part of this, the following
  20 new includes are
  21 added: <code class="filename">&lt;ext/algorithm&gt;</code>, <code class="filename">&lt;ext/functional&gt;</code>, <code class="filename">&lt;ext/iterator&gt;</code>, <code class="filename">&lt;ext/memory&gt;</code>, and <code class="filename">&lt;ext/numeric&gt;</code>.
  22 </p><p>
  23 Extensions to <code class="code">basic_filebuf</code> introduced: <code class="code">__gnu_cxx::enc_filebuf</code>, and <code class="code">__gnu_cxx::stdio_filebuf</code>.
  24 </p><p>
  25 Extensions to tree data structures added in <code class="filename">&lt;ext/rb_tree&gt;</code>.
  26 </p><p>
  27 Removal of <code class="filename">&lt;ext/tree&gt;</code>, moved to <code class="filename">&lt;backward/tree.h&gt;</code>.
  28 </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="api.rel_320"></a><code class="constant">3.2</code></h3></div></div></div><p>
  29   </p><p>Symbol versioning introduced for shared library.</p><p>Removal of include <code class="filename">&lt;backward/strstream.h&gt;</code>.</p><p>Allocator changes. Change <code class="code">__malloc_alloc</code> to <code class="code">malloc_allocator</code> and <code class="code">__new_alloc</code> to <code class="code">new_allocator</code>. </p><p> For GCC releases from 2.95 through the 3.1 series, defining
  30    <code class="literal">__USE_MALLOC</code> on the gcc command line would change the
  31    default allocation strategy to instead use <code class="code">malloc</code> and
  32    <code class="code">free</code>. For the 3.2 and 3.3 release series the same
  33    functionality was spelled <code class="literal">_GLIBCXX_FORCE_NEW</code>. From
  34    GCC 3.4 onwards the default allocator uses <code class="code">new</code> anyway,
  35    but for the optional pooling allocators the functionality is enabled by
  36    setting <code class="literal">GLIBCXX_FORCE_NEW</code> in the environment, see
  37    <a class="link" href="mt_allocator.html" title="Chapter 19. The mt_allocator">the mt allocator chapter</a>
  38    for details.
  39    </p><p>Error handling in iostreams cleaned up, made consistent. </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="api.rel_330"></a><code class="constant">3.3</code></h3></div></div></div><p>
  40   </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="api.rel_340"></a><code class="constant">3.4</code></h3></div></div></div><p>
  41   </p><p>
  42 Large file support.
  43 </p><p> Extensions for generic characters and <code class="code">char_traits</code> added in <code class="filename">&lt;ext/pod_char_traits.h&gt;</code>.
  44 </p><p>
  45 Support for <code class="code">wchar_t</code> specializations of <code class="code">basic_filebuf</code> enhanced to support <code class="code">UTF-8</code> and <code class="code">Unicode</code>, depending on host. More hosts support basic <code class="code">wchar_t</code> functionality.
  46 </p><p>
  47 Support for <code class="code">char_traits</code> beyond builtin types.
  48 </p><p>
  49 Conformant <code class="code">allocator</code> class and usage in containers. As
  50 part of this, the following extensions are
  51 added: <code class="filename">&lt;ext/bitmap_allocator.h&gt;</code>, <code class="filename">&lt;ext/debug_allocator.h&gt;</code>, <code class="filename">&lt;ext/mt_allocator.h&gt;</code>, <code class="filename">&lt;ext/malloc_allocator.h&gt;</code>,<code class="filename">&lt;ext/new_allocator.h&gt;</code>, <code class="filename">&lt;ext/pool_allocator.h&gt;</code>.
  52 </p><p>
  53 This is a change from all previous versions, and may require
  54 source-level changes due to allocator-related changes to structures
  55 names and template parameters, filenames, and file locations. Some,
  56 like <code class="code">__simple_alloc, __allocator, __alloc, </code> and <code class="code">
  57 _Alloc_traits</code> have been removed.
  58 </p><p>Default behavior of <code class="code">std::allocator</code> has changed.</p><p>
  59    Previous versions prior to 3.4 cache allocations in a memory
  60    pool, instead of passing through to call the global allocation
  61    operators (i.e., <code class="classname">__gnu_cxx::pool_allocator</code>).  More
  62    recent versions default to the
  63    simpler <code class="classname">__gnu_cxx::new_allocator</code>.
  64 </p><p> Previously, all allocators were written to the SGI
  65    style, and all STL containers expected this interface. This
  66    interface had a traits class called <code class="code">_Alloc_traits</code> that
  67    attempted to provide more information for compile-time allocation
  68    selection and optimization. This traits class had another allocator
  69    wrapper, <code class="code">__simple_alloc&lt;T,A&gt;</code>, which was a
  70    wrapper around another allocator, A, which itself is an allocator
  71    for instances of T. But wait, there's more:
  72    <code class="code">__allocator&lt;T,A&gt;</code> is another adapter.  Many of
  73    the provided allocator classes were SGI style: such classes can be
  74    changed to a conforming interface with this wrapper:
  75    <code class="code">__allocator&lt;T, __alloc&gt;</code> is thus the same as
  76    <code class="code">allocator&lt;T&gt;</code>.
  77    </p><p> The class <code class="classname">allocator</code> used the typedef
  78    <span class="type">__alloc</span> to select an underlying allocator that
  79    satisfied memory allocation requests. The selection of this
  80    underlying allocator was not user-configurable.
  81    </p><div class="table"><a id="table.extension_allocators"></a><p class="title"><strong>Table B.6. Extension Allocators</strong></p><div class="table-contents"><table class="table" summary="Extension Allocators" border="1"><colgroup><col align="left" class="c1" /><col align="left" class="c2" /><col align="left" class="c3" /><col align="left" class="c4" /></colgroup><thead><tr><th align="left">Allocator (3.4)</th><th align="left">Header (3.4)</th><th align="left">Allocator (3.[0-3])</th><th align="left">Header (3.[0-3])</th></tr></thead><tbody><tr><td align="left"><code class="classname">__gnu_cxx::new_allocator&lt;T&gt;</code></td><td align="left"><code class="filename">&lt;ext/new_allocator.h&gt;</code></td><td align="left"><code class="classname">std::__new_alloc</code></td><td align="left"><code class="filename">&lt;memory&gt;</code></td></tr><tr><td align="left"><code class="classname">__gnu_cxx::malloc_allocator&lt;T&gt;</code></td><td align="left"><code class="filename">&lt;ext/malloc_allocator.h&gt;</code></td><td align="left"><code class="classname">std::__malloc_alloc_template&lt;int&gt;</code></td><td align="left"><code class="filename">&lt;memory&gt;</code></td></tr><tr><td align="left"><code class="classname">__gnu_cxx::debug_allocator&lt;T&gt;</code></td><td align="left"><code class="filename">&lt;ext/debug_allocator.h&gt;</code></td><td align="left"><code class="classname">std::debug_alloc&lt;T&gt;</code></td><td align="left"><code class="filename">&lt;memory&gt;</code></td></tr><tr><td align="left"><code class="classname">__gnu_cxx::__pool_alloc&lt;T&gt;</code></td><td align="left"><code class="filename">&lt;ext/pool_allocator.h&gt;</code></td><td align="left"><code class="classname">std::__default_alloc_template&lt;bool,int&gt;</code></td><td align="left"><code class="filename">&lt;memory&gt;</code></td></tr><tr><td align="left"><code class="classname">__gnu_cxx::__mt_alloc&lt;T&gt;</code></td><td align="left"><code class="filename">&lt;ext/mt_allocator.h&gt;</code></td><td align="left"> </td><td align="left"> </td></tr><tr><td align="left"><code class="classname">__gnu_cxx::bitmap_allocator&lt;T&gt;</code></td><td align="left"><code class="filename">&lt;ext/bitmap_allocator.h&gt;</code></td><td align="left"> </td><td align="left"> </td></tr></tbody></table></div></div><br class="table-break" /><p> Releases after gcc-3.4 have continued to add to the collection
  82    of available allocators. All of these new allocators are
  83    standard-style. The following table includes details, along with
  84    the first released version of GCC that included the extension allocator.
  85    </p><div class="table"><a id="table.extension_allocators2"></a><p class="title"><strong>Table B.7. Extension Allocators Continued</strong></p><div class="table-contents"><table class="table" summary="Extension Allocators Continued" border="1"><colgroup><col align="left" class="c1" /><col align="left" class="c2" /><col align="left" class="c3" /></colgroup><thead><tr><th align="left">Allocator</th><th align="left">Include</th><th align="left">Version</th></tr></thead><tbody><tr><td align="left"><code class="classname">__gnu_cxx::array_allocator&lt;T&gt;</code></td><td align="left"><code class="filename">&lt;ext/array_allocator.h&gt;</code></td><td align="left">4.0.0</td></tr><tr><td align="left"><code class="classname">__gnu_cxx::throw_allocator&lt;T&gt;</code></td><td align="left"><code class="filename">&lt;ext/throw_allocator.h&gt;</code></td><td align="left">4.2.0</td></tr></tbody></table></div></div><br class="table-break" /><p>
  86 Debug mode first appears.
  87 </p><p>
  88 Precompiled header support <acronym class="acronym">PCH</acronym> support.
  89 </p><p>
  90 Macro guard for changed, from <code class="literal">_GLIBCPP_</code> to <code class="literal">_GLIBCXX_</code>.
  91 </p><p>
  92 Extension <code class="filename">&lt;ext/stdio_sync_filebuf.h&gt;</code> added.
  93 </p><p>
  94 Extension <code class="filename">&lt;ext/demangle.h&gt;</code> added.
  95 </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="api.rel_400"></a><code class="constant">4.0</code></h3></div></div></div><p>
  96   </p><p>
  97 TR1 features first appear.
  98 </p><p>
  99 Extension allocator <code class="filename">&lt;ext/array_allocator.h&gt;</code> added.
 100 </p><p>
 101 Extension <code class="code">codecvt</code> specializations moved to <code class="filename">&lt;ext/codecvt_specializations.h&gt;</code>.
 102 </p><p>
 103 Removal of <code class="filename">&lt;ext/demangle.h&gt;</code>.
 104 </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="api.rel_410"></a><code class="constant">4.1</code></h3></div></div></div><p>
 105   </p><p>
 106 Removal of <code class="filename">&lt;cassert&gt;</code> from all standard headers: now has to be explicitly included for <code class="code">std::assert</code> calls.
 107 </p><p> Extensions for policy-based data structures first added. New includes,
 108 types, namespace <code class="code">pb_assoc</code>.
 109 </p><p> Extensions for typelists added in <code class="filename">&lt;ext/typelist.h&gt;</code>.
 110 </p><p> Extension for policy-based <code class="code">basic_string</code> first added: <code class="code">__gnu_cxx::__versa_string</code> in <code class="filename">&lt;ext/vstring.h&gt;</code>.
 111 </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="api.rel_420"></a><code class="constant">4.2</code></h3></div></div></div><p>
 112   </p><p> Default visibility attributes applied to <code class="code">namespace std</code>. Support for <code class="code">-fvisibility</code>.
 113 </p><p>TR1 <code class="filename">&lt;random&gt;</code>, <code class="filename">&lt;complex&gt;</code>, and C compatibility headers added.</p><p> Extensions for concurrent programming consolidated
 114 into <code class="filename">&lt;ext/concurrence.h&gt;</code> and <code class="filename">&lt;ext/atomicity.h&gt;</code>,
 115 including change of namespace to <code class="code">__gnu_cxx</code> in some
 116 cases. Added types
 117 include <code class="code">_Lock_policy</code>, <code class="code">__concurrence_lock_error</code>, <code class="code">__concurrence_unlock_error</code>, <code class="code">__mutex</code>, <code class="code">__scoped_lock</code>.</p><p> Extensions for type traits consolidated
 118 into <code class="filename">&lt;ext/type_traits.h&gt;</code>. Additional traits are added
 119 (<code class="code">__conditional_type</code>, <code class="code">__enable_if</code>, others.)
 120 </p><p> Extensions for policy-based data structures revised. New includes,
 121 types, namespace moved to <code class="code">__pb_ds</code>.
 122 </p><p> Extensions for debug mode modified: now nested in <code class="code">namespace
 123 std::__debug</code> and extensions in <code class="code">namespace
 124 __gnu_cxx::__debug</code>.</p><p> Extensions added: <code class="filename">&lt;ext/typelist.h&gt;</code>
 125 and <code class="filename">&lt;ext/throw_allocator.h&gt;</code>.
 126 </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="api.rel_430"></a><code class="constant">4.3</code></h3></div></div></div><p>
 127   </p><p>
 128 C++0X features first appear.
 129 </p><p>TR1 <code class="filename">&lt;regex&gt;</code> and <code class="filename">&lt;cmath&gt;</code>'s mathematical special function added.
 130 </p><p>
 131 Backward include edit.
 132 </p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>Removed</p><p>
 133 <code class="filename">&lt;algobase.h&gt;</code> <code class="filename">&lt;algo.h&gt;</code> <code class="filename">&lt;alloc.h&gt;</code> <code class="filename">&lt;bvector.h&gt;</code> <code class="filename">&lt;complex.h&gt;</code>
 134 <code class="filename">&lt;defalloc.h&gt;</code> <code class="filename">&lt;deque.h&gt;</code> <code class="filename">&lt;fstream.h&gt;</code> <code class="filename">&lt;function.h&gt;</code> <code class="filename">&lt;hash_map.h&gt;</code> <code class="filename">&lt;hash_set.h&gt;</code>
 135 <code class="filename">&lt;hashtable.h&gt;</code> <code class="filename">&lt;heap.h&gt;</code> <code class="filename">&lt;iomanip.h&gt;</code> <code class="filename">&lt;iostream.h&gt;</code> <code class="filename">&lt;istream.h&gt;</code> <code class="filename">&lt;iterator.h&gt;</code>
 136 <code class="filename">&lt;list.h&gt;</code> <code class="filename">&lt;map.h&gt;</code> <code class="filename">&lt;multimap.h&gt;</code> <code class="filename">&lt;multiset.h&gt;</code> <code class="filename">&lt;new.h&gt;</code> <code class="filename">&lt;ostream.h&gt;</code> <code class="filename">&lt;pair.h&gt;</code> <code class="filename">&lt;queue.h&gt;</code> <code class="filename">&lt;rope.h&gt;</code> <code class="filename">&lt;set.h&gt;</code> <code class="filename">&lt;slist.h&gt;</code> <code class="filename">&lt;stack.h&gt;</code> <code class="filename">&lt;streambuf.h&gt;</code> <code class="filename">&lt;stream.h&gt;</code> <code class="filename">&lt;tempbuf.h&gt;</code>
 137 <code class="filename">&lt;tree.h&gt;</code> <code class="filename">&lt;vector.h&gt;</code>
 138   </p></li><li class="listitem"><p>Added</p><p>
 139   <code class="filename">&lt;hash_map&gt;</code> and <code class="filename">&lt;hash_set&gt;</code>
 140   </p></li><li class="listitem"><p>Added in C++11</p><p>
 141     <code class="filename">&lt;auto_ptr.h&gt;</code> and <code class="filename">&lt;binders.h&gt;</code>
 142   </p></li></ul></div><p>
 143 Header dependency streamlining.
 144 </p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p><code class="filename">&lt;algorithm&gt;</code> no longer includes <code class="filename">&lt;climits&gt;</code>, <code class="filename">&lt;cstring&gt;</code>, or <code class="filename">&lt;iosfwd&gt;</code> </p></li><li class="listitem"><p><code class="filename">&lt;bitset&gt;</code> no longer includes <code class="filename">&lt;istream&gt;</code> or <code class="filename">&lt;ostream&gt;</code>, adds <code class="filename">&lt;iosfwd&gt;</code> </p></li><li class="listitem"><p><code class="filename">&lt;functional&gt;</code> no longer includes <code class="filename">&lt;cstddef&gt;</code></p></li><li class="listitem"><p><code class="filename">&lt;iomanip&gt;</code> no longer includes <code class="filename">&lt;istream&gt;</code>, <code class="filename">&lt;istream&gt;</code>, or <code class="filename">&lt;functional&gt;</code>, adds <code class="filename">&lt;ioswd&gt;</code> </p></li><li class="listitem"><p><code class="filename">&lt;numeric&gt;</code> no longer includes <code class="filename">&lt;iterator&gt;</code></p></li><li class="listitem"><p><code class="filename">&lt;string&gt;</code> no longer includes <code class="filename">&lt;algorithm&gt;</code> or <code class="filename">&lt;memory&gt;</code></p></li><li class="listitem"><p><code class="filename">&lt;valarray&gt;</code> no longer includes <code class="filename">&lt;numeric&gt;</code> or <code class="filename">&lt;cstdlib&gt;</code></p></li><li class="listitem"><p><code class="filename">&lt;tr1/hashtable&gt;</code> no longer includes <code class="filename">&lt;memory&gt;</code> or <code class="filename">&lt;functional&gt;</code></p></li><li class="listitem"><p><code class="filename">&lt;tr1/memory&gt;</code> no longer includes <code class="filename">&lt;algorithm&gt;</code></p></li><li class="listitem"><p><code class="filename">&lt;tr1/random&gt;</code> no longer includes <code class="filename">&lt;algorithm&gt;</code> or <code class="filename">&lt;fstream&gt;</code></p></li></ul></div><p>
 145 Debug mode for <code class="filename">&lt;unordered_map&gt;</code> and <code class="filename">&lt;unordered_set&gt;</code>.
 146 </p><p>
 147 Parallel mode first appears.
 148 </p><p>Variadic template implementations of items in <code class="filename">&lt;tuple&gt;</code> and
 149     <code class="filename">&lt;functional&gt;</code>.
 150 </p><p>Default <code class="code">what</code> implementations give more elaborate
 151     exception strings for <code class="code">bad_cast</code>,
 152     <code class="code">bad_typeid</code>, <code class="code">bad_exception</code>, and
 153     <code class="code">bad_alloc</code>.
 154 </p><p>
 155 PCH binary files no longer installed. Instead, the source files are installed.
 156 </p><p>
 157 Namespace pb_ds moved to __gnu_pb_ds.
 158 </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="api.rel_440"></a><code class="constant">4.4</code></h3></div></div></div><p>
 159   </p><p>
 160 C++0X features.
 161 </p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>
 162     Added.
 163   </p><p>
 164     <code class="filename">&lt;atomic&gt;</code>,
 165     <code class="filename">&lt;chrono&gt;</code>,
 166     <code class="filename">&lt;condition_variable&gt;</code>,
 167     <code class="filename">&lt;forward_list&gt;</code>,
 168     <code class="filename">&lt;initializer_list&gt;</code>,
 169     <code class="filename">&lt;mutex&gt;</code>,
 170     <code class="filename">&lt;ratio&gt;</code>,
 171     <code class="filename">&lt;thread&gt;</code>
 172   </p></li><li class="listitem"><p>
 173     Updated and improved.
 174   </p><p>
 175     <code class="filename">&lt;algorithm&gt;</code>,
 176     <code class="filename">&lt;system_error&gt;</code>,
 177     <code class="filename">&lt;type_traits&gt;</code>
 178   </p></li><li class="listitem"><p>
 179     Use of the GNU extension namespace association converted to inline namespaces.
 180   </p></li><li class="listitem"><p>
 181     Preliminary support for <code class="classname">initializer_list</code>
 182     and defaulted and deleted constructors in container classes.
 183   </p></li><li class="listitem"><p>
 184     <code class="classname">unique_ptr</code>.
 185   </p></li><li class="listitem"><p>
 186     Support for new character types <span class="type">char16_t</span>
 187     and <span class="type">char32_t</span> added
 188     to <code class="classname">char_traits</code>, <code class="classname">basic_string</code>, <code class="classname">numeric_limits</code>,
 189     and assorted compile-time type traits.
 190   </p></li><li class="listitem"><p>
 191     Support for string conversions <code class="function">to_string</code>
 192     and <code class="function">to_wstring</code>.
 193   </p></li><li class="listitem"><p>
 194     Member functions taking string arguments were added to iostreams
 195     including <code class="classname">basic_filebuf</code>, <code class="classname">basic_ofstream</code>,
 196     and <code class="classname">basic_ifstream</code>.
 197   </p></li><li class="listitem"><p>
 198     Exception propagation support,
 199     including <code class="classname">exception_ptr</code>, <code class="function">current_exception</code>, <code class="function">copy_exception</code>,
 200     and <code class="function">rethrow_exception</code>.
 201   </p></li></ul></div><p>
 202 Uglification of <code class="literal">try</code> to <code class="literal">__try</code>
 203 and <code class="literal">catch</code> to <code class="literal">__catch</code>.
 204   </p><p>
 205 Audit of internal mutex usage, conversion to functions returning static
 206 local mutex.
 207   </p><p> Extensions
 208 added: <code class="filename">&lt;ext/pointer.h&gt;</code>
 209 and <code class="filename">&lt;ext/extptr_allocator.h&gt;</code>. Support
 210 for non-standard pointer types has been added
 211 to <code class="classname">vector</code>
 212 and <code class="classname">forward_list</code>.
 213 </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="api.rel_450"></a><code class="constant">4.5</code></h3></div></div></div><p>
 214   </p><p>
 215 C++0X features.
 216 </p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>
 217     Added.
 218   </p><p>
 219     <code class="filename">&lt;functional&gt;</code>,
 220     <code class="filename">&lt;future&gt;</code>,
 221     <code class="filename">&lt;random&gt;</code>
 222   </p></li><li class="listitem"><p>
 223     Updated and improved.
 224   </p><p>
 225     <code class="filename">&lt;atomic&gt;</code>,
 226     <code class="filename">&lt;system_error&gt;</code>,
 227     <code class="filename">&lt;type_traits&gt;</code>
 228   </p></li><li class="listitem"><p>
 229     Add support for explicit operators and standard layout types.
 230   </p></li></ul></div><p>
 231 Profile mode first appears.
 232 </p><p>
 233 Support for decimal floating-point arithmetic, including <code class="classname">decimal32</code>, <code class="classname">decimal64</code>, and <code class="classname">decimal128</code>.
 234 </p><p>
 235 Python pretty-printers are added for use with appropriately-advanced versions of <span class="command"><strong>gdb</strong></span>.
 236 </p><p>
 237 Audit for application of function attributes nothrow, const, pure, and noreturn.
 238 </p><p>
 239 The default behavior for comparing typeinfo names changed, so
 240 in <code class="filename">&lt;typeinfo&gt;</code>, <code class="literal">__GXX_MERGED_TYPEINFO_NAMES</code>
 241 now defaults to zero.
 242 </p><p> Extensions modified: <code class="filename">&lt;ext/throw_allocator.h&gt;</code>.
 243 </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="api.rel_460"></a><code class="constant">4.6</code></h3></div></div></div><p>
 244   Use constexpr and nullptr where appropriate throughout the library.
 245 </p><p>
 246   The library was updated to avoid including
 247   <code class="filename">&lt;stddef.h&gt;</code> in order
 248   to reduce namespace pollution.
 249 </p><p>Reference-count annotations to assist data race detectors.
 250 </p><p>
 251   Added <code class="function">make_exception_ptr</code> as an alias of
 252   <code class="function">copy_exception</code>.
 253 </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="api.rel_470"></a><code class="constant">4.7</code></h3></div></div></div><p>Use of noexcept throughout library.</p><p>Partial support for C++11 allocators first appears.</p><p>
 254   <code class="classname">monotonic_clock</code> renamed to
 255   <code class="classname">steady_clock</code> as required by the final C++11
 256   standard.
 257 </p><p>A new clocale model for newlib is available.</p><p>
 258   The library was updated to avoid including
 259   <code class="filename">&lt;unistd.h&gt;</code> in order
 260   to reduce namespace pollution.
 261 </p><p>Debug Mode was improved for unordered containers. </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="api.rel_480"></a><code class="constant">4.8</code></h3></div></div></div><p>
 262   New random number engines and distributions.
 263   Optimisations for random.
 264 </p><p>New --enable-libstdcxx-verbose configure option</p><p>
 265   The --enable-libstdcxx-time configure option becomes unnecessary given a
 266   sufficiently recent glibc.
 267 </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="api.rel_490"></a><code class="constant">4.9</code></h3></div></div></div><p> Implementation of <code class="classname">regex</code> completed. </p><p> C++14 library and TS implementations are added. </p><p> <code class="function">copy_exception</code> deprecated. </p><p> <code class="classname">__gnu_cxx::array_allocator</code> deprecated. </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="api.rel_51"></a><code class="constant">5</code></h3></div></div></div><p>
 268   ABI transition adds new implementations of several components, using the
 269   <code class="code">abi_tag</code> attribute and the <code class="code">__cxx11</code> inline
 270   namespace to distinguish the new entities from the old ones.
 271 </p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>
 272     Use of the new or old ABI can be selected per-translation unit with the
 273     <a class="xref" href="using_macros.html" title="Macros">Macros</a>.
 274   </p></li><li class="listitem"><p>
 275     New non-reference-counted <code class="classname">string</code> implementation.
 276   </p></li><li class="listitem"><p>
 277     New <code class="classname">list</code> implementation containing a new
 278     data member in order to provide O(1) <code class="function">size()</code>.
 279   </p></li><li class="listitem"><p>
 280     New <code class="classname">ios_base::failure</code> implementation inheriting
 281     from <code class="classname">system_error</code>.
 282   </p></li></ul></div><p>
 283   C++11 support completed (movable iostreams, new I/O manipulators,
 284   Unicode conversion utilities, atomic operations for
 285   <code class="classname">shared_ptr</code>, functions for notifying condition
 286   variables and making futures ready at thread exit).
 287 </p><p>
 288    Changed formatting of floating point types when
 289    <code class="code">ios_base::fixed|ios_base::scientific</code> is set in a stream's
 290    format flags.
 291 </p><p> Improved C++14 support and TS implementations. </p><p> New random number engines and distributions. </p><p>
 292   GDB Xmethods for containers and <code class="classname">unique_ptr</code> added.
 293 </p><p>
 294   <code class="classname">has_trivial_default_constructor</code>,
 295   <code class="classname">has_trivial_copy_constructor</code> and
 296   <code class="classname">has_trivial_copy_assign</code> deprecated.
 297 </p><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="api.rel_53"></a><code class="constant">5.3</code></h4></div></div></div><p> Experimental implementation of the C++ Filesystem TS added. </p></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="api.rel_61"></a><code class="constant">6</code></h3></div></div></div><p> C++14 support completed. </p><p>
 298   Support for mathematical special functions (ISO/IEC 29124:2010) added.
 299 </p><p>
 300   Assertions to check function preconditions can be enabled by defining the
 301   <a class="link" href="using_macros.html" title="Macros"><span class="symbol">_GLIBCXX_ASSERTIONS</span>
 302   macro</a>.
 303   The initial set of assertions are a subset of the checks enabled by
 304   the Debug Mode, but without the ABI changes and changes to algorithmic
 305   complexity that are caused by enabling the full Debug Mode.
 306 </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="api.rel_71"></a><code class="constant">7</code></h3></div></div></div><p>
 307   The type of exception thrown by iostreams changed to the <code class="code">cxx11</code>
 308   ABI version of <code class="classname">std::ios_base::failure</code>.
 309 </p><p>
 310   Experimental C++17 support added, including most new library features.
 311   The meaning of <code class="classname">shared_ptr&lt;T[]&gt;</code> changed to
 312   match the C++17 semantics.
 313 </p><p>
 314   <a class="xref" href="using_macros.html" title="Macros">Macros</a> added.
 315 </p><p>
 316   <code class="classname">has_trivial_default_constructor</code>,
 317   <code class="classname">has_trivial_copy_constructor</code> and
 318   <code class="classname">has_trivial_copy_assign</code> removed.
 319 </p><p>
 320 Calling a <code class="code">std::bind</code> result as volatile was deprecated for C++17.
 321 </p><p> Profile Mode was deprecated. </p><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="api.rel_72"></a><code class="constant">7.2</code></h4></div></div></div><p>
 322   Library Fundamentals TS header
 323   <code class="filename">&lt;experimental/source_location&gt;</code>
 324   added.
 325 </p></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="api.rel_73"></a><code class="constant">7.3</code></h4></div></div></div><p>
 326   Including new C++14 or C++17 headers without a suitable <code class="option">-std</code>
 327   no longer causes compilation to fail via <code class="literal">#error</code>.
 328   Instead the header is simply empty and doesn't define anything.
 329 </p></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="api.rel_81"></a><code class="constant">8</code></h3></div></div></div><p>
 330   The exceptions thrown by iostreams can now be caught by handlers for either
 331   version of <code class="classname">std::ios_base::failure</code>.
 332 </p><p>
 333   Improved experimental C++17 support. Headers
 334   <code class="filename">&lt;charconv&gt;</code> and
 335   <code class="filename">&lt;filesystem&gt;</code>.
 336   Experimental implementation of the C++17 Filesystem library added.
 337 </p><p>
 338   Experimental C++2a support
 339   (<code class="function">to_address</code> and <code class="classname">endian</code>).
 340 </p><p>
 341   AddressSanitizer annotations added to <code class="classname">std::vector</code>
 342   to detect out-of-range accesses to the unused capacity of a vector.
 343 </p><p>
 344   <code class="function">std::char_traits&lt;char16_t&gt;::to_int_type(u'\uFFFF')</code>
 345   now returns <code class="literal">0xFFFD</code>, as <code class="literal">0xFFFF</code> is
 346   used for <code class="function">std::char_traits&lt;char16_t&gt;::eof()</code>.
 347 </p><p>
 348   The extension allowing arithmetic on
 349   <code class="classname">std::atomic&lt;void*&gt;</code> and types like
 350   <code class="classname">std::atomic&lt;R(*)()&gt;</code> was deprecated.
 351 </p><p>
 352   The <code class="function">std::uncaught_exception</code> function was deprecated
 353   for C++17 mode.
 354 </p><p>
 355   The nested typedefs <span class="type">std::hash::result_type</span> and
 356   <span class="type">std::hash::argument_type</span> were deprecated for C++17 mode.
 357 </p><p>
 358   The deprecated iostream members <span class="type">ios_base::io_state</span>,
 359   <span class="type">ios_base::open_mode</span>, <span class="type">ios_base::seek_dir</span>, and
 360   <code class="function">basic_streambuf::stossc</code> were removed for C++17 mode.
 361 </p><p>
 362   The non-standard C++0x <code class="function">std::copy_exception</code> function
 363   was removed.
 364 </p><p>
 365   For <code class="option">-std=c++11</code>, <code class="option">-std=c++14</code>, and
 366   <code class="option">-std=c++17</code> modes the <code class="filename">&lt;complex.h&gt;</code>
 367   header no longer includes the C99 <code class="filename">&lt;complex.h&gt;</code>
 368   header.
 369 </p><p>
 370   For the non-default <code class="option">--enable-symvers=gnu-versioned-namespace</code>
 371   configuration, the shared library SONAME has been changed to
 372   <code class="filename">libstdc++.so.8</code>.
 373 </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="api.rel_91"></a><code class="constant">9</code></h3></div></div></div><p>
 374   C++17 header
 375   <code class="filename">&lt;memory_resource&gt;</code>
 376   added.
 377 </p><p>
 378   Experimental C++2a support improved, with new headers
 379   <code class="filename">&lt;bit&gt;</code> and
 380   <code class="filename">&lt;version&gt;</code> added.
 381   Support for new character type <span class="type">char8_t</span> added
 382   to <code class="classname">char_traits</code>, <code class="classname">basic_string</code>,
 383   <code class="classname">numeric_limits</code>,
 384   and relevant locale facets and type traits.
 385 </p><p>
 386   Experimental implementation of the Networking TS library added,
 387   with new headers
 388   <code class="filename">&lt;experimental/buffer&gt;</code>,
 389   <code class="filename">&lt;experimental/executor&gt;</code>,
 390   <code class="filename">&lt;experimental/internet&gt;</code>,
 391   <code class="filename">&lt;experimental/io_context&gt;</code>,
 392   <code class="filename">&lt;experimental/net&gt;</code>,
 393   <code class="filename">&lt;experimental/netfwd&gt;</code>,
 394   <code class="filename">&lt;experimental/socket&gt;</code>,
 395   and
 396   <code class="filename">&lt;experimental/timer&gt;</code>.
 397 </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="api.rel_101"></a><code class="constant">10</code></h3></div></div></div><p> Deprecated features removed:
 398 </p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"> Profile Mode </li><li class="listitem"><code class="classname">__gnu_cxx::array_allocator</code></li></ul></div><p>
 399 </p><p>
 400   The non-standard <code class="function">std::__is_nullptr_t</code> type trait
 401   was deprecated.
 402 </p><p>
 403   The <code class="classname">std::packaged_task</code> constructors taking
 404   an allocator argument are only defined for C++11 and C++14.
 405 </p><p>
 406   Several members of <code class="classname">std::allocator</code> were removed
 407   for C++20 mode. The removed functionality has been provided by
 408   <code class="classname">std::allocator_traits</code> since C++11 and that should
 409   be used instead.
 410 </p><p>
 411   The type of the <code class="classname">std::iterator</code> base class of
 412   <code class="classname">std::istreambuf_iterator</code> was changed to be
 413   consistent for all <code class="option">-std</code> modes.
 414   Before GCC 10.1 the base class had one type in C++98 mode and a
 415   different type in C++11 and later modes. The type in C++98 mode
 416   was changed to be the same as for C++11 and later.
 417 </p><p>
 418   Experimental C++2a support improved, with new headers
 419   <code class="filename">&lt;concepts&gt;</code>,
 420   <code class="filename">&lt;ranges&gt;</code>,
 421   <code class="filename">&lt;compare&gt;</code>,
 422   <code class="filename">&lt;coroutine&gt;</code>,
 423   <code class="filename">&lt;numbers&gt;</code>,
 424   <code class="filename">&lt;span&gt;</code>,
 425   and
 426   <code class="filename">&lt;stop_token&gt;</code>
 427   added.
 428 </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="api.rel_111"></a><code class="constant">11</code></h3></div></div></div><p>
 429   The <code class="option">--enable-cheaders=c_std</code> configuration
 430   was deprecated.
 431 </p><p>
 432   When compiling as C++20, the <code class="function">operator&gt;&gt;</code> overloads
 433   for extracting strings into character buffers only work with arrays,
 434   not raw pointers.
 435 </p><p>
 436   <code class="code">std::string::reserve(n)</code> will no longer reduce
 437   the string's capacity.
 438   Calling <code class="function">reserve()</code> with no arguments is equivalent
 439   to <code class="function">shrink_to_fit()</code>, but is deprecated.
 440   <code class="function">shrink_to_fit()</code> should be used instead.
 441 </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="api.rel_121"></a><code class="constant">12</code></h3></div></div></div><p>
 442 The <code class="function">std::random_shuffle</code> algorithms are deprecated
 443 for C++14 and later. The C++11 <code class="function">std::shuffle</code> algorithm
 444 can be used instead.
 445 </p><p>
 446 The <code class="function">std::unexpected</code> function and related typedef and
 447 accessors for the unexpected handler are deprecated for C++11 and later.
 448 Dynamic exception specifications should be replaced with <code class="code">noexcept</code>.
 449 </p><p>
 450 C++98 adaptable function utilities
 451 (<code class="code">std::bind1st</code>, <code class="code">std::unary_function</code>,
 452 <code class="code">std::ptr_fun</code>, <code class="code">std::mem_fun_ref</code> etc.)
 453 were deprecated for C++11.
 454 <code class="code">std::iterator</code>, <code class="code">std::raw_storage_iterator</code>,
 455 <code class="code">get_temporary_buffer</code>, and <code class="code">std::not_fun</code>
 456 were deprecated for C++17.
 457 </p><p>
 458 Non-standard <code class="code">std::pair</code> constructors were deprecated.
 459 A non-standard default argument for
 460 <code class="code">vector&lt;bool&gt;::insert(const_iterator, const bool&amp;)</code>
 461 was deprecated.
 462 </p><p>
 463 The <code class="literal">bitmap</code>, <code class="literal">mt</code>, and <code class="literal">pool</code>
 464 options for <code class="option">--enable-libstdcxx-allocator</code> were removed.
 465 For the <code class="literal">new</code> option, <code class="classname">std::allocator</code>
 466 no longer derives from <code class="classname">__gnu_cxx::new_allocator</code>;
 467 they both derive from <code class="classname">std::__new_allocator</code> instead.
 468 </p><p>
 469 <code class="function">std::condition_variable::wait</code> changed to be
 470 <code class="code">noexcept(false)</code> to allow thread cancellation exceptions to
 471 be thrown from <code class="function">pthread_cond_wait</code> without aborting
 472 the process.
 473 </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="api.rel_123"></a><code class="constant">12.3</code></h3></div></div></div><p>
 474 Calling a <code class="code">std::bind</code> result as volatile is ill-formed for C++20
 475 and later.
 476 </p></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="abi.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="appendix_porting.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="backwards.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">ABI Policy and Guidelines </td><td width="20%" align="center"><a accesskey="h" href="../index.html">Home</a></td><td width="40%" align="right" valign="top"> Backwards Compatibility</td></tr></table></div></body></html>