<sect1 id="appendix.porting.api" xreflabel="api">
<?dbhtml filename="api.html"?>

<sect1info>
  <keywordset>
    <keyword>ISO C++</keyword>
    <keyword>api</keyword>
    <keyword>evolution</keyword>
    <keyword>deprecation</keyword>
    <keyword>history</keyword>
  </keywordset>
</sect1info>

<title>API Evolution and Deprecation History</title>

<para>
A list of user-visible changes, in chronological order
</para>

<sect2 id="api.rel_300">
<title><constant>3.0</constant></title>

  <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>



</sect2>

<sect2 id="api.rel_310">
<title><constant>3.1</constant></title>
  <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>

</sect2>

<sect2 id="api.rel_320">
<title><constant>3.2</constant></title>
  <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
   <function>free</function>. (This same functionality is now spelled <literal>_GLIBCXX_FORCE_NEW</literal>, see
   <link linkend="manual.intro.using.macros">this page</link>
   for details.
   </para>


<para>Error handling in iostreams cleaned up, made consistent. </para>


</sect2>

<sect2 id="api.rel_330">
<title><constant>3.3</constant></title>
  <para>
  </para>
</sect2>

<sect2 id="api.rel_340">
<title><constant>3.4</constant></title>
  <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&lt;T,A&gt;</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&lt;T,A&gt;</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&lt;T, __alloc&gt;</code> is thus the same as
   <code>allocator&lt;T&gt;</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'>
<title>Extension Allocators</title>
<tgroup cols='4' align='left' colsep='1' rowsep='1'>
<colspec colname='c1'></colspec>
<colspec colname='c2'></colspec>
<colspec colname='c3'></colspec>
<colspec colname='c4'></colspec>

  <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&lt;T&gt;</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&lt;T&gt;</classname></entry>
    <entry><filename class="headerfile">ext/malloc_allocator.h</filename></entry>
    <entry><classname>std::__malloc_alloc_template&lt;int&gt;</classname></entry>
    <entry><filename class="headerfile">memory</filename></entry>
  </row>
  <row>
    <entry><classname>__gnu_cxx::debug_allocator&lt;T&gt;</classname></entry>
    <entry><filename class="headerfile">ext/debug_allocator.h</filename></entry>
    <entry><classname>std::debug_alloc&lt;T&gt;</classname></entry>
    <entry><filename class="headerfile">memory</filename></entry>
  </row>
  <row>
    <entry><classname>__gnu_cxx::__pool_alloc&lt;T&gt;</classname></entry>
    <entry><filename class="headerfile">ext/pool_allocator.h</filename></entry>
    <entry><classname>std::__default_alloc_template&lt;bool,int&gt;</classname></entry>
    <entry><filename class="headerfile">memory</filename></entry>
  </row>
  <row>
    <entry><classname>__gnu_cxx::__mt_alloc&lt;T&gt;</classname></entry>
    <entry><filename class="headerfile">ext/mt_allocator.h</filename></entry>
    <entry> </entry>
    <entry> </entry>
  </row>
  <row>
    <entry><classname>__gnu_cxx::bitmap_allocator&lt;T&gt;</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'>
<title>Extension Allocators Continued</title>
<tgroup cols='3' align='left' colsep='1' rowsep='1'>
<colspec colname='c1'></colspec>
<colspec colname='c2'></colspec>
<colspec colname='c3'></colspec>

<thead>
  <row>
    <entry>Allocator</entry>
    <entry>Include</entry>
    <entry>Version</entry>
  </row>
</thead>

<tbody>
  <row>
    <entry><classname>__gnu_cxx::array_allocator&lt;T&gt;</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&lt;T&gt;</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>


</sect2>

<sect2 id="api.rel_400">
<title><constant>4.0</constant></title>
  <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>


</sect2>

<sect2 id="api.rel_410">
<title><constant>4.1</constant></title>
  <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>

</sect2>

<sect2 id="api.rel_420">
<title><constant>4.2</constant></title>
  <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>

</sect2>

<sect2 id="api.rel_430">
<title><constant>4.3</constant></title>
  <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++0x</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>

</sect2>


<sect2 id="api.rel_440">
<title><constant>4.4</constant></title>
  <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>
</sect2>

<sect2 id="api.rel_450">
<title><constant>4.5</constant></title>
  <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 notrow, 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>
</sect2>

</sect1>
