<section xmlns="http://docbook.org/ns/docbook" version="5.0"
xml:id="appendix.porting.api" xreflabel="api">
<?dbhtml filename="api.html"?>
<info><title>API Evolution and Deprecation History</title>
<keywordset>
<keyword>ISO C++</keyword>
<keyword>api</keyword>
<keyword>evolution</keyword>
<keyword>deprecation</keyword>
<keyword>history</keyword>
</keywordset>
</info>
<para>
A list of user-visible changes, in chronological order
</para>
<section xml:id="api.rel_300"><info><title><constant>3.0</constant></title></info>
<para>
Extensions moved to <filename class="directory">include/ext</filename>.
</para>
<para>
Include files from the SGI/HP sources that pre-date the ISO standard
are added. These files are placed into
the <filename class="directory">include/backward</filename> directory and a deprecated warning
is added that notifies on inclusion (<literal>-Wno-deprecated</literal>
deactivates the warning.)
</para>
<para>Deprecated include <filename class="headerfile"><backward/strstream></filename> added.</para>
<para>Removal of include <filename class="headerfile"><builtinbuf.h></filename>, <filename class="headerfile"><indstream.h></filename>, <filename class="headerfile"><parsestream.h></filename>, <filename class="headerfile"><PlotFile.h></filename>, <filename class="headerfile"><SFile.h></filename>, <filename class="headerfile"><stdiostream.h></filename>, and <filename class="headerfile"><stream.h></filename>.
</para>
</section>
<section xml:id="api.rel_310"><info><title><constant>3.1</constant></title></info>
<para>
</para>
<para>
Extensions from SGI/HP moved from <code>namespace std</code>
to <code>namespace __gnu_cxx</code>. As part of this, the following
new includes are
added: <filename class="headerfile"><ext/algorithm></filename>, <filename class="headerfile"><ext/functional></filename>, <filename class="headerfile"><ext/iterator></filename>, <filename class="headerfile"><ext/memory></filename>, and <filename class="headerfile"><ext/numeric></filename>.
</para>
<para>
Extensions to <code>basic_filebuf</code> introduced: <code>__gnu_cxx::enc_filebuf</code>, and <code>__gnu_cxx::stdio_filebuf</code>.
</para>
<para>
Extensions to tree data structures added in <filename class="headerfile"><ext/rb_tree></filename>.
</para>
<para>
Removal of <filename class="headerfile"><ext/tree></filename>, moved to <filename class="headerfile"><backward/tree.h></filename>.
</para>
</section>
<section xml:id="api.rel_320"><info><title><constant>3.2</constant></title></info>
<para>
</para>
<para>Symbol versioning introduced for shared library.</para>
<para>Removal of include <filename class="headerfile"><backward/strstream.h></filename>.</para>
<para>Allocator changes. Change <code>__malloc_alloc</code> to <code>malloc_allocator</code> and <code>__new_alloc</code> to <code>new_allocator</code>. </para>
<para> For GCC releases from 2.95 through the 3.1 series, defining
<literal>__USE_MALLOC</literal> on the gcc command line would change the
default allocation strategy to instead use <code>malloc</code> and
<code>free</code>. For the 3.2 and 3.3 release series the same
functionality was spelled <literal>_GLIBCXX_FORCE_NEW</literal>. From
GCC 3.4 onwards the default allocator uses <code>new</code> anyway,
but for the optional pooling allocators the functionality is enabled by
setting <literal>GLIBCXX_FORCE_NEW</literal> in the environment, see
<link linkend="manual.ext.allocator.mt">the mt allocator chapter</link>
for details.
</para>
<para>Error handling in iostreams cleaned up, made consistent. </para>
</section>
<section xml:id="api.rel_330"><info><title><constant>3.3</constant></title></info>
<para>
</para>
</section>
<section xml:id="api.rel_340"><info><title><constant>3.4</constant></title></info>
<para>
</para>
<para>
Large file support.
</para>
<para> Extensions for generic characters and <code>char_traits</code> added in <filename class="headerfile"><ext/pod_char_traits.h></filename>.
</para>
<para>
Support for <code>wchar_t</code> specializations of <code>basic_filebuf</code> enhanced to support <code>UTF-8</code> and <code>Unicode</code>, depending on host. More hosts support basic <code>wchar_t</code> functionality.
</para>
<para>
Support for <code>char_traits</code> beyond builtin types.
</para>
<para>
Conformant <code>allocator</code> class and usage in containers. As
part of this, the following extensions are
added: <filename class="headerfile"><ext/bitmap_allocator.h></filename>, <filename class="headerfile"><ext/debug_allocator.h></filename>, <filename class="headerfile"><ext/mt_allocator.h></filename>, <filename class="headerfile"><ext/malloc_allocator.h></filename>,<filename class="headerfile"><ext/new_allocator.h></filename>, <filename class="headerfile"><ext/pool_allocator.h></filename>.
</para>
<para>
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>__simple_alloc, __allocator, __alloc, </code> and <code>
_Alloc_traits</code> have been removed.
</para>
<para>Default behavior of <code>std::allocator</code> has changed.</para>
<para>
Previous versions prior to 3.4 cache allocations in a memory
pool, instead of passing through to call the global allocation
operators (i.e., <classname>__gnu_cxx::pool_allocator</classname>). More
recent versions default to the
simpler <classname>__gnu_cxx::new_allocator</classname>.
</para>
<para> Previously, all allocators were written to the SGI
style, and all STL containers expected this interface. This
interface had a traits class called <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>__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>__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>__allocator<T, __alloc></code> is thus the same as
<code>allocator<T></code>.
</para>
<para> The class <classname>allocator</classname> used the typedef
<type>__alloc</type> to select an underlying allocator that
satisfied memory allocation requests. The selection of this
underlying allocator was not user-configurable.
</para>
<table frame="all" xml:id="table.extension_allocators">
<title>Extension Allocators</title>
<tgroup cols="4" align="left" colsep="1" rowsep="1">
<colspec colname="c1"/>
<colspec colname="c2"/>
<colspec colname="c3"/>
<colspec colname="c4"/>
<thead>
<row>
<entry>Allocator (3.4)</entry>
<entry>Header (3.4)</entry>
<entry>Allocator (3.[0-3])</entry>
<entry>Header (3.[0-3])</entry>
</row>
</thead>
<tbody>
<row>
<entry><classname>__gnu_cxx::new_allocator<T></classname></entry>
<entry><filename class="headerfile"><ext/new_allocator.h></filename></entry>
<entry><classname>std::__new_alloc</classname></entry>
<entry><filename class="headerfile"><memory></filename></entry>
</row>
<row>
<entry><classname>__gnu_cxx::malloc_allocator<T></classname></entry>
<entry><filename class="headerfile"><ext/malloc_allocator.h></filename></entry>
<entry><classname>std::__malloc_alloc_template<int></classname></entry>
<entry><filename class="headerfile"><memory></filename></entry>
</row>
<row>
<entry><classname>__gnu_cxx::debug_allocator<T></classname></entry>
<entry><filename class="headerfile"><ext/debug_allocator.h></filename></entry>
<entry><classname>std::debug_alloc<T></classname></entry>
<entry><filename class="headerfile"><memory></filename></entry>
</row>
<row>
<entry><classname>__gnu_cxx::__pool_alloc<T></classname></entry>
<entry><filename class="headerfile"><ext/pool_allocator.h></filename></entry>
<entry><classname>std::__default_alloc_template<bool,int></classname></entry>
<entry><filename class="headerfile"><memory></filename></entry>
</row>
<row>
<entry><classname>__gnu_cxx::__mt_alloc<T></classname></entry>
<entry><filename class="headerfile"><ext/mt_allocator.h></filename></entry>
<entry> </entry>
<entry> </entry>
</row>
<row>
<entry><classname>__gnu_cxx::bitmap_allocator<T></classname></entry>
<entry><filename class="headerfile"><ext/bitmap_allocator.h></filename></entry>
<entry> </entry>
<entry> </entry>
</row>
</tbody>
</tgroup>
</table>
<para> 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.
</para>
<table frame="all" xml:id="table.extension_allocators2">
<title>Extension Allocators Continued</title>
<tgroup cols="3" align="left" colsep="1" rowsep="1">
<colspec colname="c1"/>
<colspec colname="c2"/>
<colspec colname="c3"/>
<thead>
<row>
<entry>Allocator</entry>
<entry>Include</entry>
<entry>Version</entry>
</row>
</thead>
<tbody>
<row>
<entry><classname>__gnu_cxx::array_allocator<T></classname></entry>
<entry><filename class="headerfile"><ext/array_allocator.h></filename></entry>
<entry>4.0.0</entry>
</row>
<row>
<entry><classname>__gnu_cxx::throw_allocator<T></classname></entry>
<entry><filename class="headerfile"><ext/throw_allocator.h></filename></entry>
<entry>4.2.0</entry>
</row>
</tbody>
</tgroup>
</table>
<para>
Debug mode first appears.
</para>
<para>
Precompiled header support <acronym>PCH</acronym> support.
</para>
<para>
Macro guard for changed, from <literal>_GLIBCPP_</literal> to <literal>_GLIBCXX_</literal>.
</para>
<para>
Extension <filename class="headerfile"><ext/stdio_sync_filebuf.h></filename> added.
</para>
<para>
Extension <filename class="headerfile"><ext/demangle.h></filename> added.
</para>
</section>
<section xml:id="api.rel_400"><info><title><constant>4.0</constant></title></info>
<para>
</para>
<para>
TR1 features first appear.
</para>
<para>
Extension allocator <filename class="headerfile"><ext/array_allocator.h></filename> added.
</para>
<para>
Extension <code>codecvt</code> specializations moved to <filename class="headerfile"><ext/codecvt_specializations.h></filename>.
</para>
<para>
Removal of <filename class="headerfile"><ext/demangle.h></filename>.
</para>
</section>
<section xml:id="api.rel_410"><info><title><constant>4.1</constant></title></info>
<para>
</para>
<para>
Removal of <filename class="headerfile"><cassert></filename> from all standard headers: now has to be explicitly included for <code>std::assert</code> calls.
</para>
<para> Extensions for policy-based data structures first added. New includes,
types, namespace <code>pb_assoc</code>.
</para>
<para> Extensions for typelists added in <filename class="headerfile"><ext/typelist.h></filename>.
</para>
<para> Extension for policy-based <code>basic_string</code> first added: <code>__gnu_cxx::__versa_string</code> in <filename class="headerfile"><ext/vstring.h></filename>.
</para>
</section>
<section xml:id="api.rel_420"><info><title><constant>4.2</constant></title></info>
<para>
</para>
<para> Default visibility attributes applied to <code>namespace std</code>. Support for <code>-fvisibility</code>.
</para>
<para>TR1 <filename class="headerfile"><random></filename>, <filename class="headerfile"><complex></filename>, and C compatibility headers added.</para>
<para> Extensions for concurrent programming consolidated
into <filename class="headerfile"><ext/concurrence.h></filename> and <filename class="headerfile"><ext/atomicity.h></filename>,
including change of namespace to <code>__gnu_cxx</code> in some
cases. Added types
include <code>_Lock_policy</code>, <code>__concurrence_lock_error</code>, <code>__concurrence_unlock_error</code>, <code>__mutex</code>, <code>__scoped_lock</code>.</para>
<para> Extensions for type traits consolidated
into <filename class="headerfile"><ext/type_traits.h></filename>. Additional traits are added
(<code>__conditional_type</code>, <code>__enable_if</code>, others.)
</para>
<para> Extensions for policy-based data structures revised. New includes,
types, namespace moved to <code>__pb_ds</code>.
</para>
<para> Extensions for debug mode modified: now nested in <code>namespace
std::__debug</code> and extensions in <code>namespace
__gnu_cxx::__debug</code>.</para>
<para> Extensions added: <filename class="headerfile"><ext/typelist.h></filename>
and <filename class="headerfile"><ext/throw_allocator.h></filename>.
</para>
</section>
<section xml:id="api.rel_430"><info><title><constant>4.3</constant></title></info>
<para>
</para>
<para>
C++0X features first appear.
</para>
<para>TR1 <filename class="headerfile"><regex></filename> and <filename class="headerfile"><cmath></filename>'s mathematical special function added.
</para>
<para>
Backward include edit.
</para>
<itemizedlist>
<listitem>
<para>Removed</para>
<para>
<filename class="headerfile"><algobase.h></filename> <filename class="headerfile"><algo.h></filename> <filename class="headerfile"><alloc.h></filename> <filename class="headerfile"><bvector.h></filename> <filename class="headerfile"><complex.h></filename>
<filename class="headerfile"><defalloc.h></filename> <filename class="headerfile"><deque.h></filename> <filename class="headerfile"><fstream.h></filename> <filename class="headerfile"><function.h></filename> <filename class="headerfile"><hash_map.h></filename> <filename class="headerfile"><hash_set.h></filename>
<filename class="headerfile"><hashtable.h></filename> <filename class="headerfile"><heap.h></filename> <filename class="headerfile"><iomanip.h></filename> <filename class="headerfile"><iostream.h></filename> <filename class="headerfile"><istream.h></filename> <filename class="headerfile"><iterator.h></filename>
<filename class="headerfile"><list.h></filename> <filename class="headerfile"><map.h></filename> <filename class="headerfile"><multimap.h></filename> <filename class="headerfile"><multiset.h></filename> <filename class="headerfile"><new.h></filename> <filename class="headerfile"><ostream.h></filename> <filename class="headerfile"><pair.h></filename> <filename class="headerfile"><queue.h></filename> <filename class="headerfile"><rope.h></filename> <filename class="headerfile"><set.h></filename> <filename class="headerfile"><slist.h></filename> <filename class="headerfile"><stack.h></filename> <filename class="headerfile"><streambuf.h></filename> <filename class="headerfile"><stream.h></filename> <filename class="headerfile"><tempbuf.h></filename>
<filename class="headerfile"><tree.h></filename> <filename class="headerfile"><vector.h></filename>
</para>
</listitem>
<listitem>
<para>Added</para>
<para>
<filename class="headerfile"><hash_map></filename> and <filename class="headerfile"><hash_set></filename>
</para>
</listitem>
<listitem>
<para>Added in C++11</para>
<para>
<filename class="headerfile"><auto_ptr.h></filename> and <filename class="headerfile"><binders.h></filename>
</para>
</listitem>
</itemizedlist>
<para>
Header dependency streamlining.
</para>
<itemizedlist>
<listitem><para><filename class="headerfile"><algorithm></filename> no longer includes <filename class="headerfile"><climits></filename>, <filename class="headerfile"><cstring></filename>, or <filename class="headerfile"><iosfwd></filename> </para></listitem>
<listitem><para><filename class="headerfile"><bitset></filename> no longer includes <filename class="headerfile"><istream></filename> or <filename class="headerfile"><ostream></filename>, adds <filename class="headerfile"><iosfwd></filename> </para></listitem>
<listitem><para><filename class="headerfile"><functional></filename> no longer includes <filename class="headerfile"><cstddef></filename></para></listitem>
<listitem><para><filename class="headerfile"><iomanip></filename> no longer includes <filename class="headerfile"><istream></filename>, <filename class="headerfile"><istream></filename>, or <filename class="headerfile"><functional></filename>, adds <filename class="headerfile"><ioswd></filename> </para></listitem>
<listitem><para><filename class="headerfile"><numeric></filename> no longer includes <filename class="headerfile"><iterator></filename></para></listitem>
<listitem><para><filename class="headerfile"><string></filename> no longer includes <filename class="headerfile"><algorithm></filename> or <filename class="headerfile"><memory></filename></para></listitem>
<listitem><para><filename class="headerfile"><valarray></filename> no longer includes <filename class="headerfile"><numeric></filename> or <filename class="headerfile"><cstdlib></filename></para></listitem>
<listitem><para><filename class="headerfile"><tr1/hashtable></filename> no longer includes <filename class="headerfile"><memory></filename> or <filename class="headerfile"><functional></filename></para></listitem>
<listitem><para><filename class="headerfile"><tr1/memory></filename> no longer includes <filename class="headerfile"><algorithm></filename></para></listitem>
<listitem><para><filename class="headerfile"><tr1/random></filename> no longer includes <filename class="headerfile"><algorithm></filename> or <filename class="headerfile"><fstream></filename></para></listitem>
</itemizedlist>
<para>
Debug mode for <filename class="headerfile"><unordered_map></filename> and <filename class="headerfile"><unordered_set></filename>.
</para>
<para>
Parallel mode first appears.
</para>
<para>Variadic template implementations of items in <filename class="headerfile"><tuple></filename> and
<filename class="headerfile"><functional></filename>.
</para>
<para>Default <code>what</code> implementations give more elaborate
exception strings for <code>bad_cast</code>,
<code>bad_typeid</code>, <code>bad_exception</code>, and
<code>bad_alloc</code>.
</para>
<para>
PCH binary files no longer installed. Instead, the source files are installed.
</para>
<para>
Namespace pb_ds moved to __gnu_pb_ds.
</para>
</section>
<section xml:id="api.rel_440"><info><title><constant>4.4</constant></title></info>
<para>
</para>
<para>
C++0X features.
</para>
<itemizedlist>
<listitem>
<para>
Added.
</para>
<para>
<filename class="headerfile"><atomic></filename>,
<filename class="headerfile"><chrono></filename>,
<filename class="headerfile"><condition_variable></filename>,
<filename class="headerfile"><forward_list></filename>,
<filename class="headerfile"><initializer_list></filename>,
<filename class="headerfile"><mutex></filename>,
<filename class="headerfile"><ratio></filename>,
<filename class="headerfile"><thread></filename>
</para>
</listitem>
<listitem>
<para>
Updated and improved.
</para>
<para>
<filename class="headerfile"><algorithm></filename>,
<filename class="headerfile"><system_error></filename>,
<filename class="headerfile"><type_traits></filename>
</para>
</listitem>
<listitem>
<para>
Use of the GNU extension namespace association converted to inline namespaces.
</para>
</listitem>
<listitem>
<para>
Preliminary support for <classname>initializer_list</classname>
and defaulted and deleted constructors in container classes.
</para>
</listitem>
<listitem>
<para>
<classname>unique_ptr</classname>.
</para>
</listitem>
<listitem>
<para>
Support for new character types <type>char16_t</type>
and <type>char32_t</type> added
to <classname>char_traits</classname>, <classname>basic_string</classname>, <classname>numeric_limits</classname>,
and assorted compile-time type traits.
</para>
</listitem>
<listitem>
<para>
Support for string conversions <function>to_string</function>
and <function>to_wstring</function>.
</para>
</listitem>
<listitem>
<para>
Member functions taking string arguments were added to iostreams
including <classname>basic_filebuf</classname>, <classname>basic_ofstream</classname>,
and <classname>basic_ifstream</classname>.
</para>
</listitem>
<listitem>
<para>
Exception propagation support,
including <classname>exception_ptr</classname>, <function>current_exception</function>, <function>copy_exception</function>,
and <function>rethrow_exception</function>.
</para>
</listitem>
</itemizedlist>
<para>
Uglification of <literal>try</literal> to <literal>__try</literal>
and <literal>catch</literal> to <literal>__catch</literal>.
</para>
<para>
Audit of internal mutex usage, conversion to functions returning static
local mutex.
</para>
<para> Extensions
added: <filename class="headerfile"><ext/pointer.h></filename>
and <filename class="headerfile"><ext/extptr_allocator.h></filename>. Support
for non-standard pointer types has been added
to <classname>vector</classname>
and <classname>forward_list</classname>.
</para>
</section>
<section xml:id="api.rel_450"><info><title><constant>4.5</constant></title></info>
<para>
</para>
<para>
C++0X features.
</para>
<itemizedlist>
<listitem>
<para>
Added.
</para>
<para>
<filename class="headerfile"><functional></filename>,
<filename class="headerfile"><future></filename>,
<filename class="headerfile"><random></filename>
</para>
</listitem>
<listitem>
<para>
Updated and improved.
</para>
<para>
<filename class="headerfile"><atomic></filename>,
<filename class="headerfile"><system_error></filename>,
<filename class="headerfile"><type_traits></filename>
</para>
</listitem>
<listitem>
<para>
Add support for explicit operators and standard layout types.
</para>
</listitem>
</itemizedlist>
<para>
Profile mode first appears.
</para>
<para>
Support for decimal floating-point arithmetic, including <classname>decimal32</classname>, <classname>decimal64</classname>, and <classname>decimal128</classname>.
</para>
<para>
Python pretty-printers are added for use with appropriately-advanced versions of <command>gdb</command>.
</para>
<para>
Audit for application of function attributes nothrow, const, pure, and noreturn.
</para>
<para>
The default behavior for comparing typeinfo names changed, so
in <filename class="headerfile"><typeinfo></filename>, <literal>__GXX_MERGED_TYPEINFO_NAMES</literal>
now defaults to zero.
</para>
<para> Extensions modified: <filename class="headerfile"><ext/throw_allocator.h></filename>.
</para>
</section>
<section xml:id="api.rel_460"><info><title><constant>4.6</constant></title></info>
<para>
Use constexpr and nullptr where appropriate throughout the library.
</para>
<para>
The library was updated to avoid including
<filename class="headerfile"><stddef.h></filename> in order
to reduce namespace pollution.
</para>
<para>Reference-count annotations to assist data race detectors.
</para>
<para>
Added <function>make_exception_ptr</function> as an alias of
<function>copy_exception</function>.
</para>
</section>
<section xml:id="api.rel_470"><info><title><constant>4.7</constant></title></info>
<para>Use of noexcept throughout library.</para>
<para>Partial support for C++11 allocators first appears.</para>
<para>
<classname>monotonic_clock</classname> renamed to
<classname>steady_clock</classname> as required by the final C++11
standard.
</para>
<para>A new clocale model for newlib is available.</para>
<para>
The library was updated to avoid including
<filename class="headerfile"><unistd.h></filename> in order
to reduce namespace pollution.
</para>
<para>Debug Mode was improved for unordered containers. </para>
</section>
<section xml:id="api.rel_480"><info><title><constant>4.8</constant></title></info>
<para>
New random number engines and distributions.
Optimisations for random.
</para>
<para>New --enable-libstdcxx-verbose configure option</para>
<para>
The --enable-libstdcxx-time configure option becomes unnecessary given a
sufficiently recent glibc.
</para>
</section>
<section xml:id="api.rel_490"><info><title><constant>4.9</constant></title></info>
<para> Implementation of <classname>regex</classname> completed. </para>
<para> C++14 library and TS implementations are added. </para>
<para> <function>copy_exception</function> deprecated. </para>
<para> <classname>__gnu_cxx::array_allocator</classname> deprecated. </para>
</section>
<section xml:id="api.rel_51"><info><title><constant>5</constant></title></info>
<para>
ABI transition adds new implementations of several components, using the
<code>abi_tag</code> attribute and the <code>__cxx11</code> inline
namespace to distinguish the new entities from the old ones.
</para>
<itemizedlist>
<listitem>
<para>
Use of the new or old ABI can be selected per-translation unit with the
<xref linkend="manual.intro.using.macros"><symbol>_GLIBCXX_USE_CXX11_ABI</symbol>
macro</xref>.
</para>
</listitem>
<listitem>
<para>
New non-reference-counted <classname>string</classname> implementation.
</para>
</listitem>
<listitem>
<para>
New <classname>list</classname> implementation containing a new
data member in order to provide O(1) <function>size()</function>.
</para>
</listitem>
<listitem>
<para>
New <classname>ios_base::failure</classname> implementation inheriting
from <classname>system_error</classname>.
</para>
</listitem>
</itemizedlist>
<para>
C++11 support completed (movable iostreams, new I/O manipulators,
Unicode conversion utilities, atomic operations for
<classname>shared_ptr</classname>, functions for notifying condition
variables and making futures ready at thread exit).
</para>
<para>
Changed formatting of floating point types when
<code>ios_base::fixed|ios_base::scientific</code> is set in a stream's
format flags.
</para>
<para> Improved C++14 support and TS implementations. </para>
<para> New random number engines and distributions. </para>
<para>
GDB Xmethods for containers and <classname>unique_ptr</classname> added.
</para>
<para>
<classname>has_trivial_default_constructor</classname>,
<classname>has_trivial_copy_constructor</classname> and
<classname>has_trivial_copy_assign</classname> deprecated.
</para>
<section xml:id="api.rel_53"><info><title><constant>5.3</constant></title></info>
<para> Experimental implementation of the C++ Filesystem TS added. </para>
</section>
</section>
<section xml:id="api.rel_61"><info><title><constant>6</constant></title></info>
<para> C++14 support completed. </para>
<para>
Support for mathematical special functions (ISO/IEC 29124:2010) added.
</para>
<para>
Assertions to check function preconditions can be enabled by defining the
<link linkend="manual.intro.using.macros"><symbol>_GLIBCXX_ASSERTIONS</symbol>
macro</link>.
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.
</para>
</section>
<section xml:id="api.rel_71"><info><title><constant>7</constant></title></info>
<para>
The type of exception thrown by iostreams changed to the <code>cxx11</code>
ABI version of <classname>std::ios_base::failure</classname>.
</para>
<para>
Experimental C++17 support added, including most new library features.
The meaning of <classname>shared_ptr<T[]></classname> changed to
match the C++17 semantics.
</para>
<para>
<xref linkend="manual.intro.using.macros"><symbol>_GLIBCXX_RELEASE</symbol>
macro</xref> added.
</para>
<para>
<classname>has_trivial_default_constructor</classname>,
<classname>has_trivial_copy_constructor</classname> and
<classname>has_trivial_copy_assign</classname> removed.
</para>
<para>
Calling a <code>std::bind</code> result as volatile was deprecated for C++17.
</para>
<para> Profile Mode was deprecated. </para>
<section xml:id="api.rel_72"><info><title><constant>7.2</constant></title></info>
<para>
Library Fundamentals TS header
<filename class="headerfile"><experimental/source_location></filename>
added.
</para>
</section>
<section xml:id="api.rel_73"><info><title><constant>7.3</constant></title></info>
<para>
Including new C++14 or C++17 headers without a suitable <option>-std</option>
no longer causes compilation to fail via <literal>#error</literal>.
Instead the header is simply empty and doesn't define anything.
</para>
</section>
</section>
<section xml:id="api.rel_81"><info><title><constant>8</constant></title></info>
<para>
The exceptions thrown by iostreams can now be caught by handlers for either
version of <classname>std::ios_base::failure</classname>.
</para>
<para>
Improved experimental C++17 support. Headers
<filename class="headerfile"><charconv></filename> and
<filename class="headerfile"><filesystem></filename>.
Experimental implementation of the C++17 Filesystem library added.
</para>
<para>
Experimental C++2a support
(<function>to_address</function> and <classname>endian</classname>).
</para>
<para>
AddressSanitizer annotations added to <classname>std::vector</classname>
to detect out-of-range accesses to the unused capacity of a vector.
</para>
<para>
<function>std::char_traits<char16_t>::to_int_type(u'\uFFFF')</function>
now returns <literal>0xFFFD</literal>, as <literal>0xFFFF</literal> is
used for <function>std::char_traits<char16_t>::eof()</function>.
</para>
<para>
The extension allowing arithmetic on
<classname>std::atomic<void*></classname> and types like
<classname>std::atomic<R(*)()></classname> was deprecated.
</para>
<para>
The <function>std::uncaught_exception</function> function was deprecated
for C++17 mode.
</para>
<para>
The nested typedefs <type>std::hash::result_type</type> and
<type>std::hash::argument_type</type> were deprecated for C++17 mode.
</para>
<para>
The deprecated iostream members <type>ios_base::io_state</type>,
<type>ios_base::open_mode</type>, <type>ios_base::seek_dir</type>, and
<function>basic_streambuf::stossc</function> were removed for C++17 mode.
</para>
<para>
The non-standard C++0x <function>std::copy_exception</function> function
was removed.
</para>
<para>
For <option>-std=c++11</option>, <option>-std=c++14</option>, and
<option>-std=c++17</option> modes the <filename><complex.h></filename>
header no longer includes the C99 <filename><complex.h></filename>
header.
</para>
<para>
For the non-default <option>--enable-symvers=gnu-versioned-namespace</option>
configuration, the shared library SONAME has been changed to
<filename>libstdc++.so.8</filename>.
</para>
<para>
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 (<option>-std=c++NN</option>) modes, only in
<option>-std=gnu++NN</option> modes.
</para>
</section>
<section xml:id="api.rel_91"><info><title><constant>9</constant></title></info>
<para>
C++17 header
<filename class="headerfile"><memory_resource></filename>
added.
</para>
<para>
Experimental C++2a support improved, with new headers
<filename class="headerfile"><bit></filename> and
<filename class="headerfile"><version></filename> added.
Support for new character type <type>char8_t</type> added
to <classname>char_traits</classname>, <classname>basic_string</classname>,
<classname>numeric_limits</classname>,
and relevant locale facets and type traits.
</para>
<para>
Experimental implementation of the Networking TS library added,
with new headers
<filename class="headerfile"><experimental/buffer></filename>,
<filename class="headerfile"><experimental/executor></filename>,
<filename class="headerfile"><experimental/internet></filename>,
<filename class="headerfile"><experimental/io_context></filename>,
<filename class="headerfile"><experimental/net></filename>,
<filename class="headerfile"><experimental/netfwd></filename>,
<filename class="headerfile"><experimental/socket></filename>,
and
<filename class="headerfile"><experimental/timer></filename>.
</para>
</section>
<section xml:id="api.rel_101"><info><title><constant>10</constant></title></info>
<para> Deprecated features removed:
<itemizedlist>
<listitem> Profile Mode </listitem>
<listitem> <classname>__gnu_cxx::array_allocator</classname> </listitem>
</itemizedlist>
</para>
<para>
The non-standard <function>std::__is_nullptr_t</function> type trait
was deprecated.
</para>
<para>
The <classname>std::packaged_task</classname> constructors taking
an allocator argument are only defined for C++11 and C++14.
</para>
<para>
Several members of <classname>std::allocator</classname> were removed
for C++20 mode. The removed functionality has been provided by
<classname>std::allocator_traits</classname> since C++11 and that should
be used instead.
</para>
<para>
The type of the <classname>std::iterator</classname> base class of
<classname>std::istreambuf_iterator</classname> was changed to be
consistent for all <option>-std</option> 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.
</para>
<para>
Experimental C++2a support improved, with new headers
<filename class="headerfile"><concepts></filename>,
<filename class="headerfile"><ranges></filename>,
<filename class="headerfile"><compare></filename>,
<filename class="headerfile"><coroutine></filename>,
<filename class="headerfile"><numbers></filename>,
<filename class="headerfile"><span></filename>,
and
<filename class="headerfile"><stop_token></filename>
added.
</para>
<para>
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 <option>-std=gnu++20</option> mode.
</para>
</section>
<section xml:id="api.rel_111"><info><title><constant>11</constant></title></info>
<para>
The <option>--enable-cheaders=c_std</option> configuration
was deprecated.
</para>
<para>
When compiling as C++20, the <function>operator>></function> overloads
for extracting strings into character buffers only work with arrays,
not raw pointers.
</para>
<para>
<code>std::string::reserve(n)</code> will no longer reduce
the string's capacity.
Calling <function>reserve()</function> with no arguments is equivalent
to <function>shrink_to_fit()</function>, but is deprecated.
<function>shrink_to_fit()</function> should be used instead.
</para>
</section>
<section xml:id="api.rel_121"><info><title><constant>12</constant></title></info>
<para>
The <function>std::random_shuffle</function> algorithms are deprecated
for C++14 and later. The C++11 <function>std::shuffle</function> algorithm
can be used instead.
</para>
<para>
The <function>std::unexpected</function> 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>noexcept</code>.
</para>
<para>
C++98 adaptable function utilities
(<code>std::bind1st</code>, <code>std::unary_function</code>,
<code>std::ptr_fun</code>, <code>std::mem_fun_ref</code> etc.)
were deprecated for C++11.
<code>std::iterator</code>, <code>std::raw_storage_iterator</code>,
<code>get_temporary_buffer</code>, and <code>std::not_fun</code>
were deprecated for C++17.
</para>
<para>
Non-standard <code>std::pair</code> constructors were deprecated.
A non-standard default argument for
<code>vector<bool>::insert(const_iterator, const bool&)</code>
was deprecated.
</para>
<para>
The <literal>bitmap</literal>, <literal>mt</literal>, and <literal>pool</literal>
options for <option>--enable-libstdcxx-allocator</option> were removed.
For the <literal>new</literal> option, <classname>std::allocator</classname>
no longer derives from <classname>__gnu_cxx::new_allocator</classname>;
they both derive from <classname>std::__new_allocator</classname> instead.
</para>
<para>
<function>std::condition_variable::wait</function> changed to be
<code>noexcept(false)</code> to allow thread cancellation exceptions to
be thrown from <function>pthread_cond_wait</function> without aborting
the process.
</para>
</section>
<section xml:id="api.rel_123"><info><title><constant>12.3</constant></title></info>
<para>
Calling a <code>std::bind</code> result as volatile is ill-formed for C++20
and later.
</para>
</section>
<section xml:id="api.rel_131"><info><title><constant>13</constant></title></info>
<para>
Tunables <variable>glibcxx.eh_pool.obj_count</variable> and
<variable>glibcxx.eh_pool.obj_size</variable> were added.
</para>
</section>
</section>