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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>API Evolution and Deprecation History</title><meta name="generator" content="DocBook XSL Stylesheets Vsnapshot" /><meta name="keywords" content="ISO C++, api, evolution, deprecation, history" /><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="appendix_porting.html" title="Appendix B.  Porting and Maintenance" /><link rel="prev" href="abi.html" title="ABI Policy and Guidelines" /><link rel="next" href="backwards.html" title="Backwards Compatibility" /></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">API Evolution and Deprecation History</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="abi.html">Prev</a> </td><th width="60%" align="center">Appendix B. 
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>
6A 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>
8Extensions moved to <code class="filename">include/ext</code>.
9  </p><p>
10Include files from the SGI/HP sources that pre-date the ISO standard
11are added. These files are placed into
12the <code class="filename">include/backward</code> directory and a deprecated warning
13is added that notifies on inclusion (<code class="literal">-Wno-deprecated</code>
14deactivates 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>
18Extensions from SGI/HP moved from <code class="code">namespace std</code>
19to <code class="code">namespace __gnu_cxx</code>. As part of this, the following
20new includes are
21added: <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>
23Extensions 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>
25Extensions to tree data structures added in <code class="filename">&lt;ext/rb_tree&gt;</code>.
26</p><p>
27Removal 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 20. 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>
42Large 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>
45Support 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>
47Support for <code class="code">char_traits</code> beyond builtin types.
48</p><p>
49Conformant <code class="code">allocator</code> class and usage in containers. As
50part of this, the following extensions are
51added: <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>
53This is a change from all previous versions, and may require
54source-level changes due to allocator-related changes to structures
55names and template parameters, filenames, and file locations. Some,
56like <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>
86Debug mode first appears.
87</p><p>
88Precompiled header support <acronym class="acronym">PCH</acronym> support.
89</p><p>
90Macro guard for changed, from <code class="literal">_GLIBCPP_</code> to <code class="literal">_GLIBCXX_</code>.
91</p><p>
92Extension <code class="filename">&lt;ext/stdio_sync_filebuf.h&gt;</code> added.
93</p><p>
94Extension <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>
97TR1 features first appear.
98</p><p>
99Extension allocator <code class="filename">&lt;ext/array_allocator.h&gt;</code> added.
100</p><p>
101Extension <code class="code">codecvt</code> specializations moved to <code class="filename">&lt;ext/codecvt_specializations.h&gt;</code>.
102</p><p>
103Removal 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>
106Removal 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,
108types, 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
114into <code class="filename">&lt;ext/concurrence.h&gt;</code> and <code class="filename">&lt;ext/atomicity.h&gt;</code>,
115including change of namespace to <code class="code">__gnu_cxx</code> in some
116cases. Added types
117include <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
118into <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,
121types, namespace moved to <code class="code">__pb_ds</code>.
122</p><p> Extensions for debug mode modified: now nested in <code class="code">namespace
123std::__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>
125and <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>
128C++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>
131Backward 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>
143Header 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>
145Debug mode for <code class="filename">&lt;unordered_map&gt;</code> and <code class="filename">&lt;unordered_set&gt;</code>.
146</p><p>
147Parallel 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>
155PCH binary files no longer installed. Instead, the source files are installed.
156</p><p>
157Namespace 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>
160C++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>
202Uglification of <code class="literal">try</code> to <code class="literal">__try</code>
203and <code class="literal">catch</code> to <code class="literal">__catch</code>.
204  </p><p>
205Audit of internal mutex usage, conversion to functions returning static
206local mutex.
207  </p><p> Extensions
208added: <code class="filename">&lt;ext/pointer.h&gt;</code>
209and <code class="filename">&lt;ext/extptr_allocator.h&gt;</code>. Support
210for non-standard pointer types has been added
211to <code class="classname">vector</code>
212and <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>
215C++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>
231Profile mode first appears.
232</p><p>
233Support 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>
235Python pretty-printers are added for use with appropriately-advanced versions of <span class="command"><strong>gdb</strong></span>.
236</p><p>
237Audit for application of function attributes nothrow, const, pure, and noreturn.
238</p><p>
239The default behavior for comparing typeinfo names changed, so
240in <code class="filename">&lt;typeinfo&gt;</code>, <code class="literal">__GXX_MERGED_TYPEINFO_NAMES</code>
241now 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="xref" href="using_macros.html" title="Macros">Macros</a>.
302  The initial set of assertions are a subset of the checks enabled by
303  the Debug Mode, but without the ABI changes and changes to algorithmic
304  complexity that are caused by enabling the full Debug Mode.
305</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>
306  The type of exception thrown by iostreams changed to the <code class="code">cxx11</code>
307  ABI version of <code class="classname">std::ios_base::failure</code>.
308</p><p>
309  Experimental C++17 support added, including most new library features.
310  The meaning of <code class="classname">shared_ptr&lt;T[]&gt;</code> changed to
311  match the C++17 semantics.
312</p><p>
313  <a class="xref" href="using_macros.html" title="Macros">Macros</a> added.
314</p><p>
315  <code class="classname">has_trivial_default_constructor</code>,
316  <code class="classname">has_trivial_copy_constructor</code> and
317  <code class="classname">has_trivial_copy_assign</code> removed.
318</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>
319  Library Fundamentals TS header
320  <code class="filename">&lt;experimental/source_location&gt;</code>
321  added.
322</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>
323  Including new C++14 or C++17 headers without a suitable <code class="option">-std</code>
324  no longer causes compilation to fail via <code class="literal">#error</code>.
325  Instead the header is simply empty and doesn't define anything.
326</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>
327  The exceptions thrown by iostreams can now be caught by handlers for either
328  version of <code class="classname">std::ios_base::failure</code>.
329</p><p>
330  Improved experimental C++17 support. Headers
331  <code class="filename">&lt;charconv&gt;</code> and
332  <code class="filename">&lt;filesystem&gt;</code>.
333  Experimental implementation of the C++17 Filesystem library added.
334</p><p>
335  Experimental C++2a support
336  (<code class="function">to_address</code> and <code class="classname">endian</code>).
337</p><p>
338  AddressSanitizer annotations added to <code class="classname">std::vector</code>
339  to detect out-of-range accesses to the unused capacity of a vector.
340</p><p>
341  <code class="function">std::char_traits&lt;char16_t&gt;::to_int_type(u'\uFFFF')</code>
342  now returns <code class="literal">0xFFFD</code>, as <code class="literal">0xFFFF</code> is
343  used for <code class="function">std::char_traits&lt;char16_t&gt;::eof()</code>.
344</p><p>
345  The extension allowing arithmetic on
346  <code class="classname">std::atomic&lt;void*&gt;</code> and types like
347  <code class="classname">std::atomic&lt;R(*)()&gt;</code> was deprecated.
348</p><p>
349  The <code class="function">std::uncaught_exception</code> function was deprecated
350  for C++17 mode.
351</p><p>
352  The nested typedefs <span class="type">std::hash::result_type</span> and
353  <span class="type">std::hash::argument_type</span> were deprecated for C++17 mode.
354</p><p>
355  The deprecated iostream members <span class="type">ios_base::io_state</span>,
356  <span class="type">ios_base::open_mode</span>, <span class="type">ios_base::seek_dir</span>, and
357  <code class="function">basic_streambuf::stossc</code> were removed for C++17 mode.
358</p><p>
359  The non-standard C++0x <code class="function">std::copy_exception</code> function
360  was removed.
361</p><p>
362  For <code class="option">-std=c++11</code>, <code class="option">-std=c++14</code>, and
363  <code class="option">-std=c++17</code> modes the <code class="filename">&lt;complex.h&gt;</code>
364  header no longer includes the C99 <code class="filename">&lt;complex.h&gt;</code>
365  header.
366</p><p>
367  For the non-default <code class="option">--enable-symvers=gnu-versioned-namespace</code>
368  configuration, the shared library SONAME has been changed to
369  <code class="filename">libstdc++.so.8</code>.
370</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>
371  C++17 header
372  <code class="filename">&lt;memory_resource&gt;</code>
373  added.
374</p><p>
375  Experimental C++2a support improved, with new headers
376  <code class="filename">&lt;bit&gt;</code> and
377  <code class="filename">&lt;version&gt;</code> added.
378  Support for new character type <span class="type">char8_t</span> added
379  to <code class="classname">char_traits</code>, <code class="classname">basic_string</code>,
380  <code class="classname">numeric_limits</code>,
381  and relevant locale facets and type traits.
382</p><p>
383  Experimental implementation of the Networking TS library added,
384  with new headers
385  <code class="filename">&lt;experimental/buffer&gt;</code>,
386  <code class="filename">&lt;experimental/executor&gt;</code>,
387  <code class="filename">&lt;experimental/internet&gt;</code>,
388  <code class="filename">&lt;experimental/io_context&gt;</code>,
389  <code class="filename">&lt;experimental/net&gt;</code>,
390  <code class="filename">&lt;experimental/netfwd&gt;</code>,
391  <code class="filename">&lt;experimental/socket&gt;</code>,
392  and
393  <code class="filename">&lt;experimental/timer&gt;</code>.
394</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>