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<!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.
Porting and Maintenance
</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>
A list of user-visible changes, in chronological order
</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>
Extensions moved to <code class="filename">include/ext</code>.
</p><p>
Include files from the SGI/HP sources that pre-date the ISO standard
are added. These files are placed into
the <code class="filename">include/backward</code> directory and a deprecated warning
is added that notifies on inclusion (<code class="literal">-Wno-deprecated</code>
deactivates the warning.)
</p><p>Deprecated include <code class="filename"><backward/strstream></code> added.</p><p>Removal of include <code class="filename"><builtinbuf.h></code>, <code class="filename"><indstream.h></code>, <code class="filename"><parsestream.h></code>, <code class="filename"><PlotFile.h></code>, <code class="filename"><SFile.h></code>, <code class="filename"><stdiostream.h></code>, and <code class="filename"><stream.h></code>.
</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>
</p><p>
Extensions from SGI/HP moved from <code class="code">namespace std</code>
to <code class="code">namespace __gnu_cxx</code>. As part of this, the following
new includes are
added: <code class="filename"><ext/algorithm></code>, <code class="filename"><ext/functional></code>, <code class="filename"><ext/iterator></code>, <code class="filename"><ext/memory></code>, and <code class="filename"><ext/numeric></code>.
</p><p>
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>.
</p><p>
Extensions to tree data structures added in <code class="filename"><ext/rb_tree></code>.
</p><p>
Removal of <code class="filename"><ext/tree></code>, moved to <code class="filename"><backward/tree.h></code>.
</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>
</p><p>Symbol versioning introduced for shared library.</p><p>Removal of include <code class="filename"><backward/strstream.h></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
<code class="literal">__USE_MALLOC</code> on the gcc command line would change the
default allocation strategy to instead use <code class="code">malloc</code> and
<code class="code">free</code>. For the 3.2 and 3.3 release series the same
functionality was spelled <code class="literal">_GLIBCXX_FORCE_NEW</code>. From
GCC 3.4 onwards the default allocator uses <code class="code">new</code> anyway,
but for the optional pooling allocators the functionality is enabled by
setting <code class="literal">GLIBCXX_FORCE_NEW</code> in the environment, see
<a class="link" href="mt_allocator.html" title="Chapter 19. The mt_allocator">the mt allocator chapter</a>
for details.
</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>
</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>
</p><p>
Large file support.
</p><p> Extensions for generic characters and <code class="code">char_traits</code> added in <code class="filename"><ext/pod_char_traits.h></code>.
</p><p>
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.
</p><p>
Support for <code class="code">char_traits</code> beyond builtin types.
</p><p>
Conformant <code class="code">allocator</code> class and usage in containers. As
part of this, the following extensions are
added: <code class="filename"><ext/bitmap_allocator.h></code>, <code class="filename"><ext/debug_allocator.h></code>, <code class="filename"><ext/mt_allocator.h></code>, <code class="filename"><ext/malloc_allocator.h></code>,<code class="filename"><ext/new_allocator.h></code>, <code class="filename"><ext/pool_allocator.h></code>.
</p><p>
This is a change from all previous versions, and may require
source-level changes due to allocator-related changes to structures
names and template parameters, filenames, and file locations. Some,
like <code class="code">__simple_alloc, __allocator, __alloc, </code> and <code class="code">
_Alloc_traits</code> have been removed.
</p><p>Default behavior of <code class="code">std::allocator</code> has changed.</p><p>
Previous versions prior to 3.4 cache allocations in a memory
pool, instead of passing through to call the global allocation
operators (i.e., <code class="classname">__gnu_cxx::pool_allocator</code>). More
recent versions default to the
simpler <code class="classname">__gnu_cxx::new_allocator</code>.
</p><p> Previously, all allocators were written to the SGI
style, and all STL containers expected this interface. This
interface had a traits class called <code class="code">_Alloc_traits</code> that
attempted to provide more information for compile-time allocation
selection and optimization. This traits class had another allocator
wrapper, <code class="code">__simple_alloc<T,A></code>, which was a
wrapper around another allocator, A, which itself is an allocator
for instances of T. But wait, there's more:
<code class="code">__allocator<T,A></code> is another adapter. Many of
the provided allocator classes were SGI style: such classes can be
changed to a conforming interface with this wrapper:
<code class="code">__allocator<T, __alloc></code> is thus the same as
<code class="code">allocator<T></code>.
</p><p> The class <code class="classname">allocator</code> used the typedef
<span class="type">__alloc</span> to select an underlying allocator that
satisfied memory allocation requests. The selection of this
underlying allocator was not user-configurable.
</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<T></code></td><td align="left"><code class="filename"><ext/new_allocator.h></code></td><td align="left"><code class="classname">std::__new_alloc</code></td><td align="left"><code class="filename"><memory></code></td></tr><tr><td align="left"><code class="classname">__gnu_cxx::malloc_allocator<T></code></td><td align="left"><code class="filename"><ext/malloc_allocator.h></code></td><td align="left"><code class="classname">std::__malloc_alloc_template<int></code></td><td align="left"><code class="filename"><memory></code></td></tr><tr><td align="left"><code class="classname">__gnu_cxx::debug_allocator<T></code></td><td align="left"><code class="filename"><ext/debug_allocator.h></code></td><td align="left"><code class="classname">std::debug_alloc<T></code></td><td align="left"><code class="filename"><memory></code></td></tr><tr><td align="left"><code class="classname">__gnu_cxx::__pool_alloc<T></code></td><td align="left"><code class="filename"><ext/pool_allocator.h></code></td><td align="left"><code class="classname">std::__default_alloc_template<bool,int></code></td><td align="left"><code class="filename"><memory></code></td></tr><tr><td align="left"><code class="classname">__gnu_cxx::__mt_alloc<T></code></td><td align="left"><code class="filename"><ext/mt_allocator.h></code></td><td align="left"> </td><td align="left"> </td></tr><tr><td align="left"><code class="classname">__gnu_cxx::bitmap_allocator<T></code></td><td align="left"><code class="filename"><ext/bitmap_allocator.h></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
of available allocators. All of these new allocators are
standard-style. The following table includes details, along with
the first released version of GCC that included the extension allocator.
</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<T></code></td><td align="left"><code class="filename"><ext/array_allocator.h></code></td><td align="left">4.0.0</td></tr><tr><td align="left"><code class="classname">__gnu_cxx::throw_allocator<T></code></td><td align="left"><code class="filename"><ext/throw_allocator.h></code></td><td align="left">4.2.0</td></tr></tbody></table></div></div><br class="table-break" /><p>
Debug mode first appears.
</p><p>
Precompiled header support <acronym class="acronym">PCH</acronym> support.
</p><p>
Macro guard for changed, from <code class="literal">_GLIBCPP_</code> to <code class="literal">_GLIBCXX_</code>.
</p><p>
Extension <code class="filename"><ext/stdio_sync_filebuf.h></code> added.
</p><p>
Extension <code class="filename"><ext/demangle.h></code> added.
</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>
</p><p>
TR1 features first appear.
</p><p>
Extension allocator <code class="filename"><ext/array_allocator.h></code> added.
</p><p>
Extension <code class="code">codecvt</code> specializations moved to <code class="filename"><ext/codecvt_specializations.h></code>.
</p><p>
Removal of <code class="filename"><ext/demangle.h></code>.
</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>
</p><p>
Removal of <code class="filename"><cassert></code> from all standard headers: now has to be explicitly included for <code class="code">std::assert</code> calls.
</p><p> Extensions for policy-based data structures first added. New includes,
types, namespace <code class="code">pb_assoc</code>.
</p><p> Extensions for typelists added in <code class="filename"><ext/typelist.h></code>.
</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"><ext/vstring.h></code>.
</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>
</p><p> Default visibility attributes applied to <code class="code">namespace std</code>. Support for <code class="code">-fvisibility</code>.
</p><p>TR1 <code class="filename"><random></code>, <code class="filename"><complex></code>, and C compatibility headers added.</p><p> Extensions for concurrent programming consolidated
into <code class="filename"><ext/concurrence.h></code> and <code class="filename"><ext/atomicity.h></code>,
including change of namespace to <code class="code">__gnu_cxx</code> in some
cases. Added types
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
into <code class="filename"><ext/type_traits.h></code>. Additional traits are added
(<code class="code">__conditional_type</code>, <code class="code">__enable_if</code>, others.)
</p><p> Extensions for policy-based data structures revised. New includes,
types, namespace moved to <code class="code">__pb_ds</code>.
</p><p> Extensions for debug mode modified: now nested in <code class="code">namespace
std::__debug</code> and extensions in <code class="code">namespace
__gnu_cxx::__debug</code>.</p><p> Extensions added: <code class="filename"><ext/typelist.h></code>
and <code class="filename"><ext/throw_allocator.h></code>.
</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>
</p><p>
C++0X features first appear.
</p><p>TR1 <code class="filename"><regex></code> and <code class="filename"><cmath></code>'s mathematical special function added.
</p><p>
Backward include edit.
</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>Removed</p><p>
<code class="filename"><algobase.h></code> <code class="filename"><algo.h></code> <code class="filename"><alloc.h></code> <code class="filename"><bvector.h></code> <code class="filename"><complex.h></code>
<code class="filename"><defalloc.h></code> <code class="filename"><deque.h></code> <code class="filename"><fstream.h></code> <code class="filename"><function.h></code> <code class="filename"><hash_map.h></code> <code class="filename"><hash_set.h></code>
<code class="filename"><hashtable.h></code> <code class="filename"><heap.h></code> <code class="filename"><iomanip.h></code> <code class="filename"><iostream.h></code> <code class="filename"><istream.h></code> <code class="filename"><iterator.h></code>
<code class="filename"><list.h></code> <code class="filename"><map.h></code> <code class="filename"><multimap.h></code> <code class="filename"><multiset.h></code> <code class="filename"><new.h></code> <code class="filename"><ostream.h></code> <code class="filename"><pair.h></code> <code class="filename"><queue.h></code> <code class="filename"><rope.h></code> <code class="filename"><set.h></code> <code class="filename"><slist.h></code> <code class="filename"><stack.h></code> <code class="filename"><streambuf.h></code> <code class="filename"><stream.h></code> <code class="filename"><tempbuf.h></code>
<code class="filename"><tree.h></code> <code class="filename"><vector.h></code>
</p></li><li class="listitem"><p>Added</p><p>
<code class="filename"><hash_map></code> and <code class="filename"><hash_set></code>
</p></li><li class="listitem"><p>Added in C++11</p><p>
<code class="filename"><auto_ptr.h></code> and <code class="filename"><binders.h></code>
</p></li></ul></div><p>
Header dependency streamlining.
</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p><code class="filename"><algorithm></code> no longer includes <code class="filename"><climits></code>, <code class="filename"><cstring></code>, or <code class="filename"><iosfwd></code> </p></li><li class="listitem"><p><code class="filename"><bitset></code> no longer includes <code class="filename"><istream></code> or <code class="filename"><ostream></code>, adds <code class="filename"><iosfwd></code> </p></li><li class="listitem"><p><code class="filename"><functional></code> no longer includes <code class="filename"><cstddef></code></p></li><li class="listitem"><p><code class="filename"><iomanip></code> no longer includes <code class="filename"><istream></code>, <code class="filename"><istream></code>, or <code class="filename"><functional></code>, adds <code class="filename"><ioswd></code> </p></li><li class="listitem"><p><code class="filename"><numeric></code> no longer includes <code class="filename"><iterator></code></p></li><li class="listitem"><p><code class="filename"><string></code> no longer includes <code class="filename"><algorithm></code> or <code class="filename"><memory></code></p></li><li class="listitem"><p><code class="filename"><valarray></code> no longer includes <code class="filename"><numeric></code> or <code class="filename"><cstdlib></code></p></li><li class="listitem"><p><code class="filename"><tr1/hashtable></code> no longer includes <code class="filename"><memory></code> or <code class="filename"><functional></code></p></li><li class="listitem"><p><code class="filename"><tr1/memory></code> no longer includes <code class="filename"><algorithm></code></p></li><li class="listitem"><p><code class="filename"><tr1/random></code> no longer includes <code class="filename"><algorithm></code> or <code class="filename"><fstream></code></p></li></ul></div><p>
Debug mode for <code class="filename"><unordered_map></code> and <code class="filename"><unordered_set></code>.
</p><p>
Parallel mode first appears.
</p><p>Variadic template implementations of items in <code class="filename"><tuple></code> and
<code class="filename"><functional></code>.
</p><p>Default <code class="code">what</code> implementations give more elaborate
exception strings for <code class="code">bad_cast</code>,
<code class="code">bad_typeid</code>, <code class="code">bad_exception</code>, and
<code class="code">bad_alloc</code>.
</p><p>
PCH binary files no longer installed. Instead, the source files are installed.
</p><p>
Namespace pb_ds moved to __gnu_pb_ds.
</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>
</p><p>
C++0X features.
</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>
Added.
</p><p>
<code class="filename"><atomic></code>,
<code class="filename"><chrono></code>,
<code class="filename"><condition_variable></code>,
<code class="filename"><forward_list></code>,
<code class="filename"><initializer_list></code>,
<code class="filename"><mutex></code>,
<code class="filename"><ratio></code>,
<code class="filename"><thread></code>
</p></li><li class="listitem"><p>
Updated and improved.
</p><p>
<code class="filename"><algorithm></code>,
<code class="filename"><system_error></code>,
<code class="filename"><type_traits></code>
</p></li><li class="listitem"><p>
Use of the GNU extension namespace association converted to inline namespaces.
</p></li><li class="listitem"><p>
Preliminary support for <code class="classname">initializer_list</code>
and defaulted and deleted constructors in container classes.
</p></li><li class="listitem"><p>
<code class="classname">unique_ptr</code>.
</p></li><li class="listitem"><p>
Support for new character types <span class="type">char16_t</span>
and <span class="type">char32_t</span> added
to <code class="classname">char_traits</code>, <code class="classname">basic_string</code>, <code class="classname">numeric_limits</code>,
and assorted compile-time type traits.
</p></li><li class="listitem"><p>
Support for string conversions <code class="function">to_string</code>
and <code class="function">to_wstring</code>.
</p></li><li class="listitem"><p>
Member functions taking string arguments were added to iostreams
including <code class="classname">basic_filebuf</code>, <code class="classname">basic_ofstream</code>,
and <code class="classname">basic_ifstream</code>.
</p></li><li class="listitem"><p>
Exception propagation support,
including <code class="classname">exception_ptr</code>, <code class="function">current_exception</code>, <code class="function">copy_exception</code>,
and <code class="function">rethrow_exception</code>.
</p></li></ul></div><p>
Uglification of <code class="literal">try</code> to <code class="literal">__try</code>
and <code class="literal">catch</code> to <code class="literal">__catch</code>.
</p><p>
Audit of internal mutex usage, conversion to functions returning static
local mutex.
</p><p> Extensions
added: <code class="filename"><ext/pointer.h></code>
and <code class="filename"><ext/extptr_allocator.h></code>. Support
for non-standard pointer types has been added
to <code class="classname">vector</code>
and <code class="classname">forward_list</code>.
</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>
</p><p>
C++0X features.
</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>
Added.
</p><p>
<code class="filename"><functional></code>,
<code class="filename"><future></code>,
<code class="filename"><random></code>
</p></li><li class="listitem"><p>
Updated and improved.
</p><p>
<code class="filename"><atomic></code>,
<code class="filename"><system_error></code>,
<code class="filename"><type_traits></code>
</p></li><li class="listitem"><p>
Add support for explicit operators and standard layout types.
</p></li></ul></div><p>
Profile mode first appears.
</p><p>
Support for decimal floating-point arithmetic, including <code class="classname">decimal32</code>, <code class="classname">decimal64</code>, and <code class="classname">decimal128</code>.
</p><p>
Python pretty-printers are added for use with appropriately-advanced versions of <span class="command"><strong>gdb</strong></span>.
</p><p>
Audit for application of function attributes nothrow, const, pure, and noreturn.
</p><p>
The default behavior for comparing typeinfo names changed, so
in <code class="filename"><typeinfo></code>, <code class="literal">__GXX_MERGED_TYPEINFO_NAMES</code>
now defaults to zero.
</p><p> Extensions modified: <code class="filename"><ext/throw_allocator.h></code>.
</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>
Use constexpr and nullptr where appropriate throughout the library.
</p><p>
The library was updated to avoid including
<code class="filename"><stddef.h></code> in order
to reduce namespace pollution.
</p><p>Reference-count annotations to assist data race detectors.
</p><p>
Added <code class="function">make_exception_ptr</code> as an alias of
<code class="function">copy_exception</code>.
</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>
<code class="classname">monotonic_clock</code> renamed to
<code class="classname">steady_clock</code> as required by the final C++11
standard.
</p><p>A new clocale model for newlib is available.</p><p>
The library was updated to avoid including
<code class="filename"><unistd.h></code> in order
to reduce namespace pollution.
</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>
New random number engines and distributions.
Optimisations for random.
</p><p>New --enable-libstdcxx-verbose configure option</p><p>
The --enable-libstdcxx-time configure option becomes unnecessary given a
sufficiently recent glibc.
</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>
ABI transition adds new implementations of several components, using the
<code class="code">abi_tag</code> attribute and the <code class="code">__cxx11</code> inline
namespace to distinguish the new entities from the old ones.
</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>
Use of the new or old ABI can be selected per-translation unit with the
<a class="xref" href="using_macros.html" title="Macros">Macros</a>.
</p></li><li class="listitem"><p>
New non-reference-counted <code class="classname">string</code> implementation.
</p></li><li class="listitem"><p>
New <code class="classname">list</code> implementation containing a new
data member in order to provide O(1) <code class="function">size()</code>.
</p></li><li class="listitem"><p>
New <code class="classname">ios_base::failure</code> implementation inheriting
from <code class="classname">system_error</code>.
</p></li></ul></div><p>
C++11 support completed (movable iostreams, new I/O manipulators,
Unicode conversion utilities, atomic operations for
<code class="classname">shared_ptr</code>, functions for notifying condition
variables and making futures ready at thread exit).
</p><p>
Changed formatting of floating point types when
<code class="code">ios_base::fixed|ios_base::scientific</code> is set in a stream's
format flags.
</p><p> Improved C++14 support and TS implementations. </p><p> New random number engines and distributions. </p><p>
GDB Xmethods for containers and <code class="classname">unique_ptr</code> added.
</p><p>
<code class="classname">has_trivial_default_constructor</code>,
<code class="classname">has_trivial_copy_constructor</code> and
<code class="classname">has_trivial_copy_assign</code> deprecated.
</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>
Support for mathematical special functions (ISO/IEC 29124:2010) added.
</p><p>
Assertions to check function preconditions can be enabled by defining the
<a class="link" href="using_macros.html" title="Macros"><span class="symbol">_GLIBCXX_ASSERTIONS</span>
macro</a>.
The initial set of assertions are a subset of the checks enabled by
the Debug Mode, but without the ABI changes and changes to algorithmic
complexity that are caused by enabling the full Debug Mode.
</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>
The type of exception thrown by iostreams changed to the <code class="code">cxx11</code>
ABI version of <code class="classname">std::ios_base::failure</code>.
</p><p>
Experimental C++17 support added, including most new library features.
The meaning of <code class="classname">shared_ptr<T[]></code> changed to
match the C++17 semantics.
</p><p>
<a class="xref" href="using_macros.html" title="Macros">Macros</a> added.
</p><p>
<code class="classname">has_trivial_default_constructor</code>,
<code class="classname">has_trivial_copy_constructor</code> and
<code class="classname">has_trivial_copy_assign</code> removed.
</p><p>
Calling a <code class="code">std::bind</code> result as volatile was deprecated for C++17.
</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>
Library Fundamentals TS header
<code class="filename"><experimental/source_location></code>
added.
</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>
Including new C++14 or C++17 headers without a suitable <code class="option">-std</code>
no longer causes compilation to fail via <code class="literal">#error</code>.
Instead the header is simply empty and doesn't define anything.
</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>
The exceptions thrown by iostreams can now be caught by handlers for either
version of <code class="classname">std::ios_base::failure</code>.
</p><p>
Improved experimental C++17 support. Headers
<code class="filename"><charconv></code> and
<code class="filename"><filesystem></code>.
Experimental implementation of the C++17 Filesystem library added.
</p><p>
Experimental C++2a support
(<code class="function">to_address</code> and <code class="classname">endian</code>).
</p><p>
AddressSanitizer annotations added to <code class="classname">std::vector</code>
to detect out-of-range accesses to the unused capacity of a vector.
</p><p>
<code class="function">std::char_traits<char16_t>::to_int_type(u'\uFFFF')</code>
now returns <code class="literal">0xFFFD</code>, as <code class="literal">0xFFFF</code> is
used for <code class="function">std::char_traits<char16_t>::eof()</code>.
</p><p>
The extension allowing arithmetic on
<code class="classname">std::atomic<void*></code> and types like
<code class="classname">std::atomic<R(*)()></code> was deprecated.
</p><p>
The <code class="function">std::uncaught_exception</code> function was deprecated
for C++17 mode.
</p><p>
The nested typedefs <span class="type">std::hash::result_type</span> and
<span class="type">std::hash::argument_type</span> were deprecated for C++17 mode.
</p><p>
The deprecated iostream members <span class="type">ios_base::io_state</span>,
<span class="type">ios_base::open_mode</span>, <span class="type">ios_base::seek_dir</span>, and
<code class="function">basic_streambuf::stossc</code> were removed for C++17 mode.
</p><p>
The non-standard C++0x <code class="function">std::copy_exception</code> function
was removed.
</p><p>
For <code class="option">-std=c++11</code>, <code class="option">-std=c++14</code>, and
<code class="option">-std=c++17</code> modes the <code class="filename"><complex.h></code>
header no longer includes the C99 <code class="filename"><complex.h></code>
header.
</p><p>
For the non-default <code class="option">--enable-symvers=gnu-versioned-namespace</code>
configuration, the shared library SONAME has been changed to
<code class="filename">libstdc++.so.8</code>.
</p><p>
The extension allowing containers to be instantiated with an allocator
that doesn't match the container's value type is no longer allowed in
strict (<code class="option">-std=c++NN</code>) modes, only in
<code class="option">-std=gnu++NN</code> modes.
</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>
C++17 header
<code class="filename"><memory_resource></code>
added.
</p><p>
Experimental C++2a support improved, with new headers
<code class="filename"><bit></code> and
<code class="filename"><version></code> added.
Support for new character type <span class="type">char8_t</span> added
to <code class="classname">char_traits</code>, <code class="classname">basic_string</code>,
<code class="classname">numeric_limits</code>,
and relevant locale facets and type traits.
</p><p>
Experimental implementation of the Networking TS library added,
with new headers
<code class="filename"><experimental/buffer></code>,
<code class="filename"><experimental/executor></code>,
<code class="filename"><experimental/internet></code>,
<code class="filename"><experimental/io_context></code>,
<code class="filename"><experimental/net></code>,
<code class="filename"><experimental/netfwd></code>,
<code class="filename"><experimental/socket></code>,
and
<code class="filename"><experimental/timer></code>.
</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:
</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>
</p><p>
The non-standard <code class="function">std::__is_nullptr_t</code> type trait
was deprecated.
</p><p>
The <code class="classname">std::packaged_task</code> constructors taking
an allocator argument are only defined for C++11 and C++14.
</p><p>
Several members of <code class="classname">std::allocator</code> were removed
for C++20 mode. The removed functionality has been provided by
<code class="classname">std::allocator_traits</code> since C++11 and that should
be used instead.
</p><p>
The type of the <code class="classname">std::iterator</code> base class of
<code class="classname">std::istreambuf_iterator</code> was changed to be
consistent for all <code class="option">-std</code> modes.
Before GCC 10.1 the base class had one type in C++98 mode and a
different type in C++11 and later modes. The type in C++98 mode
was changed to be the same as for C++11 and later.
</p><p>
Experimental C++2a support improved, with new headers
<code class="filename"><concepts></code>,
<code class="filename"><ranges></code>,
<code class="filename"><compare></code>,
<code class="filename"><coroutine></code>,
<code class="filename"><numbers></code>,
<code class="filename"><span></code>,
and
<code class="filename"><stop_token></code>
added.
</p><p>
The extension allowing containers to be instantiated with an allocator
that doesn't match the container's value type is no longer allowed in
C++20 mode, even in non-strict <code class="option">-std=gnu++20</code> mode.
</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>
The <code class="option">--enable-cheaders=c_std</code> configuration
was deprecated.
</p><p>
When compiling as C++20, the <code class="function">operator>></code> overloads
for extracting strings into character buffers only work with arrays,
not raw pointers.
</p><p>
<code class="code">std::string::reserve(n)</code> will no longer reduce
the string's capacity.
Calling <code class="function">reserve()</code> with no arguments is equivalent
to <code class="function">shrink_to_fit()</code>, but is deprecated.
<code class="function">shrink_to_fit()</code> should be used instead.
</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>
The <code class="function">std::random_shuffle</code> algorithms are deprecated
for C++14 and later. The C++11 <code class="function">std::shuffle</code> algorithm
can be used instead.
</p><p>
The <code class="function">std::unexpected</code> function and related typedef and
accessors for the unexpected handler are deprecated for C++11 and later.
Dynamic exception specifications should be replaced with <code class="code">noexcept</code>.
</p><p>
C++98 adaptable function utilities
(<code class="code">std::bind1st</code>, <code class="code">std::unary_function</code>,
<code class="code">std::ptr_fun</code>, <code class="code">std::mem_fun_ref</code> etc.)
were deprecated for C++11.
<code class="code">std::iterator</code>, <code class="code">std::raw_storage_iterator</code>,
<code class="code">get_temporary_buffer</code>, and <code class="code">std::not_fun</code>
were deprecated for C++17.
</p><p>
Non-standard <code class="code">std::pair</code> constructors were deprecated.
A non-standard default argument for
<code class="code">vector<bool>::insert(const_iterator, const bool&)</code>
was deprecated.
</p><p>
The <code class="literal">bitmap</code>, <code class="literal">mt</code>, and <code class="literal">pool</code>
options for <code class="option">--enable-libstdcxx-allocator</code> were removed.
For the <code class="literal">new</code> option, <code class="classname">std::allocator</code>
no longer derives from <code class="classname">__gnu_cxx::new_allocator</code>;
they both derive from <code class="classname">std::__new_allocator</code> instead.
</p><p>
<code class="function">std::condition_variable::wait</code> changed to be
<code class="code">noexcept(false)</code> to allow thread cancellation exceptions to
be thrown from <code class="function">pthread_cond_wait</code> without aborting
the process.
</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>
Calling a <code class="code">std::bind</code> result as volatile is ill-formed for C++20
and later.
</p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="api.rel_131"></a><code class="constant">13</code></h3></div></div></div><p>
Tunables <span style="color: red"><variable>glibcxx.eh_pool.obj_count</variable></span> and
<span style="color: red"><variable>glibcxx.eh_pool.obj_size</variable></span> were added.
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