libstdc++-v3/doc/xml/manual/evolution.xml

   1 <section xmlns="http://docbook.org/ns/docbook" version="5.0"
   2          xml:id="appendix.porting.api" xreflabel="api">
   3 <?dbhtml filename="api.html"?>
   4
   5 <info><title>API Evolution and Deprecation History</title>
   6   <keywordset>
   7     <keyword>ISO C++</keyword>
   8     <keyword>api</keyword>
   9     <keyword>evolution</keyword>
  10     <keyword>deprecation</keyword>
  11     <keyword>history</keyword>
  12   </keywordset>
  13 </info>
  14
  15
  16 <para>
  17 A list of user-visible changes, in chronological order
  18 </para>
  19
  20 <section xml:id="api.rel_300"><info><title><constant>3.0</constant></title></info>
  21
  22
  23   <para>
  24 Extensions moved to <filename class="directory">include/ext</filename>.
  25   </para>
  26
  27 <para>
  28 Include files from the SGI/HP sources that pre-date the ISO standard
  29 are added. These files are placed into
  30 the <filename class="directory">include/backward</filename> directory and a deprecated warning
  31 is added that notifies on inclusion (<literal>-Wno-deprecated</literal>
  32 deactivates the warning.)
  33 </para>
  34
  35 <para>Deprecated include <filename class="headerfile">&lt;backward/strstream&gt;</filename> added.</para>
  36
  37 <para>Removal of include <filename class="headerfile">&lt;builtinbuf.h&gt;</filename>, <filename class="headerfile">&lt;indstream.h&gt;</filename>, <filename class="headerfile">&lt;parsestream.h&gt;</filename>, <filename class="headerfile">&lt;PlotFile.h&gt;</filename>, <filename class="headerfile">&lt;SFile.h&gt;</filename>, <filename class="headerfile">&lt;stdiostream.h&gt;</filename>, and <filename class="headerfile">&lt;stream.h&gt;</filename>.
  38 </para>
  39
  40
  41
  42 </section>
  43
  44 <section xml:id="api.rel_310"><info><title><constant>3.1</constant></title></info>
  45
  46   <para>
  47   </para>
  48
  49 <para>
  50 Extensions from SGI/HP moved from <code>namespace std</code>
  51 to <code>namespace __gnu_cxx</code>. As part of this, the following
  52 new includes are
  53 added: <filename class="headerfile">&lt;ext/algorithm&gt;</filename>, <filename class="headerfile">&lt;ext/functional&gt;</filename>, <filename class="headerfile">&lt;ext/iterator&gt;</filename>, <filename class="headerfile">&lt;ext/memory&gt;</filename>, and <filename class="headerfile">&lt;ext/numeric&gt;</filename>.
  54 </para>
  55
  56 <para>
  57 Extensions to <code>basic_filebuf</code> introduced: <code>__gnu_cxx::enc_filebuf</code>, and <code>__gnu_cxx::stdio_filebuf</code>.
  58 </para>
  59
  60 <para>
  61 Extensions to tree data structures added in <filename class="headerfile">&lt;ext/rb_tree&gt;</filename>.
  62 </para>
  63
  64 <para>
  65 Removal of <filename class="headerfile">&lt;ext/tree&gt;</filename>, moved to <filename class="headerfile">&lt;backward/tree.h&gt;</filename>.
  66 </para>
  67
  68 </section>
  69
  70 <section xml:id="api.rel_320"><info><title><constant>3.2</constant></title></info>
  71
  72   <para>
  73   </para>
  74 <para>Symbol versioning introduced for shared library.</para>
  75
  76 <para>Removal of include <filename class="headerfile">&lt;backward/strstream.h&gt;</filename>.</para>
  77
  78 <para>Allocator changes. Change <code>__malloc_alloc</code> to <code>malloc_allocator</code> and <code>__new_alloc</code> to <code>new_allocator</code>. </para>
  79
  80    <para> For GCC releases from 2.95 through the 3.1 series, defining
  81    <literal>__USE_MALLOC</literal> on the gcc command line would change the
  82    default allocation strategy to instead use <code>malloc</code> and
  83    <code>free</code>. For the 3.2 and 3.3 release series the same
  84    functionality was spelled <literal>_GLIBCXX_FORCE_NEW</literal>. From
  85    GCC 3.4 onwards the default allocator uses <code>new</code> anyway,
  86    but for the optional pooling allocators the functionality is enabled by
  87    setting <literal>GLIBCXX_FORCE_NEW</literal> in the environment, see
  88    <link linkend="manual.ext.allocator.mt">the mt allocator chapter</link>
  89    for details.
  90    </para>
  91
  92
  93 <para>Error handling in iostreams cleaned up, made consistent. </para>
  94
  95
  96 </section>
  97
  98 <section xml:id="api.rel_330"><info><title><constant>3.3</constant></title></info>
  99
 100   <para>
 101   </para>
 102 </section>
 103
 104 <section xml:id="api.rel_340"><info><title><constant>3.4</constant></title></info>
 105
 106   <para>
 107   </para>
 108 <para>
 109 Large file support.
 110 </para>
 111
 112 <para> Extensions for generic characters and <code>char_traits</code> added in <filename class="headerfile">&lt;ext/pod_char_traits.h&gt;</filename>.
 113 </para>
 114
 115 <para>
 116 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.
 117 </para>
 118
 119 <para>
 120 Support for <code>char_traits</code> beyond builtin types.
 121 </para>
 122
 123 <para>
 124 Conformant <code>allocator</code> class and usage in containers. As
 125 part of this, the following extensions are
 126 added: <filename class="headerfile">&lt;ext/bitmap_allocator.h&gt;</filename>, <filename class="headerfile">&lt;ext/debug_allocator.h&gt;</filename>, <filename class="headerfile">&lt;ext/mt_allocator.h&gt;</filename>, <filename class="headerfile">&lt;ext/malloc_allocator.h&gt;</filename>,<filename class="headerfile">&lt;ext/new_allocator.h&gt;</filename>, <filename class="headerfile">&lt;ext/pool_allocator.h&gt;</filename>.
 127 </para>
 128
 129 <para>
 130 This is a change from all previous versions, and may require
 131 source-level changes due to allocator-related changes to structures
 132 names and template parameters, filenames, and file locations. Some,
 133 like <code>__simple_alloc, __allocator, __alloc, </code> and <code>
 134 _Alloc_traits</code> have been removed.
 135 </para>
 136
 137 <para>Default behavior of <code>std::allocator</code> has changed.</para>
 138
 139 <para>
 140    Previous versions prior to 3.4 cache allocations in a memory
 141    pool, instead of passing through to call the global allocation
 142    operators (i.e., <classname>__gnu_cxx::pool_allocator</classname>).  More
 143    recent versions default to the
 144    simpler <classname>__gnu_cxx::new_allocator</classname>.
 145 </para>
 146
 147 <para> Previously, all allocators were written to the SGI
 148    style, and all STL containers expected this interface. This
 149    interface had a traits class called <code>_Alloc_traits</code> that
 150    attempted to provide more information for compile-time allocation
 151    selection and optimization. This traits class had another allocator
 152    wrapper, <code>__simple_alloc&lt;T,A&gt;</code>, which was a
 153    wrapper around another allocator, A, which itself is an allocator
 154    for instances of T. But wait, there's more:
 155    <code>__allocator&lt;T,A&gt;</code> is another adapter.  Many of
 156    the provided allocator classes were SGI style: such classes can be
 157    changed to a conforming interface with this wrapper:
 158    <code>__allocator&lt;T, __alloc&gt;</code> is thus the same as
 159    <code>allocator&lt;T&gt;</code>.
 160    </para>
 161
 162    <para> The class <classname>allocator</classname> used the typedef
 163    <type>__alloc</type> to select an underlying allocator that
 164    satisfied memory allocation requests. The selection of this
 165    underlying allocator was not user-configurable.
 166    </para>
 167
 168 <table frame="all" xml:id="table.extension_allocators">
 169 <title>Extension Allocators</title>
 170
 171 <tgroup cols="4" align="left" colsep="1" rowsep="1">
 172 <colspec colname="c1"/>
 173 <colspec colname="c2"/>
 174 <colspec colname="c3"/>
 175 <colspec colname="c4"/>
 176
 177   <thead>
 178     <row>
 179       <entry>Allocator (3.4)</entry>
 180       <entry>Header (3.4)</entry>
 181       <entry>Allocator (3.[0-3])</entry>
 182       <entry>Header (3.[0-3])</entry>
 183     </row>
 184   </thead>
 185
 186   <tbody>
 187   <row>
 188     <entry><classname>__gnu_cxx::new_allocator&lt;T&gt;</classname></entry>
 189     <entry><filename class="headerfile">&lt;ext/new_allocator.h&gt;</filename></entry>
 190     <entry><classname>std::__new_alloc</classname></entry>
 191     <entry><filename class="headerfile">&lt;memory&gt;</filename></entry>
 192   </row>
 193   <row>
 194     <entry><classname>__gnu_cxx::malloc_allocator&lt;T&gt;</classname></entry>
 195     <entry><filename class="headerfile">&lt;ext/malloc_allocator.h&gt;</filename></entry>
 196     <entry><classname>std::__malloc_alloc_template&lt;int&gt;</classname></entry>
 197     <entry><filename class="headerfile">&lt;memory&gt;</filename></entry>
 198   </row>
 199   <row>
 200     <entry><classname>__gnu_cxx::debug_allocator&lt;T&gt;</classname></entry>
 201     <entry><filename class="headerfile">&lt;ext/debug_allocator.h&gt;</filename></entry>
 202     <entry><classname>std::debug_alloc&lt;T&gt;</classname></entry>
 203     <entry><filename class="headerfile">&lt;memory&gt;</filename></entry>
 204   </row>
 205   <row>
 206     <entry><classname>__gnu_cxx::__pool_alloc&lt;T&gt;</classname></entry>
 207     <entry><filename class="headerfile">&lt;ext/pool_allocator.h&gt;</filename></entry>
 208     <entry><classname>std::__default_alloc_template&lt;bool,int&gt;</classname></entry>
 209     <entry><filename class="headerfile">&lt;memory&gt;</filename></entry>
 210   </row>
 211   <row>
 212     <entry><classname>__gnu_cxx::__mt_alloc&lt;T&gt;</classname></entry>
 213     <entry><filename class="headerfile">&lt;ext/mt_allocator.h&gt;</filename></entry>
 214     <entry> </entry>
 215     <entry> </entry>
 216   </row>
 217   <row>
 218     <entry><classname>__gnu_cxx::bitmap_allocator&lt;T&gt;</classname></entry>
 219     <entry><filename class="headerfile">&lt;ext/bitmap_allocator.h&gt;</filename></entry>
 220     <entry> </entry>
 221     <entry> </entry>
 222   </row>
 223   </tbody>
 224 </tgroup>
 225 </table>
 226
 227    <para> Releases after gcc-3.4 have continued to add to the collection
 228    of available allocators. All of these new allocators are
 229    standard-style. The following table includes details, along with
 230    the first released version of GCC that included the extension allocator.
 231    </para>
 232
 233 <table frame="all" xml:id="table.extension_allocators2">
 234 <title>Extension Allocators Continued</title>
 235
 236 <tgroup cols="3" align="left" colsep="1" rowsep="1">
 237 <colspec colname="c1"/>
 238 <colspec colname="c2"/>
 239 <colspec colname="c3"/>
 240
 241 <thead>
 242   <row>
 243     <entry>Allocator</entry>
 244     <entry>Include</entry>
 245     <entry>Version</entry>
 246   </row>
 247 </thead>
 248
 249 <tbody>
 250   <row>
 251     <entry><classname>__gnu_cxx::array_allocator&lt;T&gt;</classname></entry>
 252     <entry><filename class="headerfile">&lt;ext/array_allocator.h&gt;</filename></entry>
 253     <entry>4.0.0</entry>
 254   </row>
 255   <row>
 256     <entry><classname>__gnu_cxx::throw_allocator&lt;T&gt;</classname></entry>
 257     <entry><filename class="headerfile">&lt;ext/throw_allocator.h&gt;</filename></entry>
 258     <entry>4.2.0</entry>
 259   </row>
 260 </tbody>
 261 </tgroup>
 262 </table>
 263
 264
 265 <para>
 266 Debug mode first appears.
 267 </para>
 268
 269 <para>
 270 Precompiled header support <acronym>PCH</acronym> support.
 271 </para>
 272
 273 <para>
 274 Macro guard for changed, from <literal>_GLIBCPP_</literal> to <literal>_GLIBCXX_</literal>.
 275 </para>
 276
 277 <para>
 278 Extension <filename class="headerfile">&lt;ext/stdio_sync_filebuf.h&gt;</filename> added.
 279 </para>
 280
 281 <para>
 282 Extension <filename class="headerfile">&lt;ext/demangle.h&gt;</filename> added.
 283 </para>
 284
 285
 286 </section>
 287
 288 <section xml:id="api.rel_400"><info><title><constant>4.0</constant></title></info>
 289
 290   <para>
 291   </para>
 292 <para>
 293 TR1 features first appear.
 294 </para>
 295
 296 <para>
 297 Extension allocator <filename class="headerfile">&lt;ext/array_allocator.h&gt;</filename> added.
 298 </para>
 299
 300 <para>
 301 Extension <code>codecvt</code> specializations moved to <filename class="headerfile">&lt;ext/codecvt_specializations.h&gt;</filename>.
 302 </para>
 303
 304 <para>
 305 Removal of <filename class="headerfile">&lt;ext/demangle.h&gt;</filename>.
 306 </para>
 307
 308
 309 </section>
 310
 311 <section xml:id="api.rel_410"><info><title><constant>4.1</constant></title></info>
 312
 313   <para>
 314   </para>
 315
 316
 317 <para>
 318 Removal of <filename class="headerfile">&lt;cassert&gt;</filename> from all standard headers: now has to be explicitly included for <code>std::assert</code> calls.
 319 </para>
 320
 321 <para> Extensions for policy-based data structures first added. New includes,
 322 types, namespace <code>pb_assoc</code>.
 323 </para>
 324
 325
 326
 327 <para> Extensions for typelists added in <filename class="headerfile">&lt;ext/typelist.h&gt;</filename>.
 328 </para>
 329
 330 <para> Extension for policy-based <code>basic_string</code> first added: <code>__gnu_cxx::__versa_string</code> in <filename class="headerfile">&lt;ext/vstring.h&gt;</filename>.
 331 </para>
 332
 333 </section>
 334
 335 <section xml:id="api.rel_420"><info><title><constant>4.2</constant></title></info>
 336
 337   <para>
 338   </para>
 339
 340
 341 <para> Default visibility attributes applied to <code>namespace std</code>. Support for <code>-fvisibility</code>.
 342 </para>
 343
 344 <para>TR1 <filename class="headerfile">&lt;random&gt;</filename>, <filename class="headerfile">&lt;complex&gt;</filename>, and C compatibility headers added.</para>
 345
 346 <para> Extensions for concurrent programming consolidated
 347 into <filename class="headerfile">&lt;ext/concurrence.h&gt;</filename> and <filename class="headerfile">&lt;ext/atomicity.h&gt;</filename>,
 348 including change of namespace to <code>__gnu_cxx</code> in some
 349 cases. Added types
 350 include <code>_Lock_policy</code>, <code>__concurrence_lock_error</code>, <code>__concurrence_unlock_error</code>, <code>__mutex</code>, <code>__scoped_lock</code>.</para>
 351
 352 <para> Extensions for type traits consolidated
 353 into <filename class="headerfile">&lt;ext/type_traits.h&gt;</filename>. Additional traits are added
 354 (<code>__conditional_type</code>, <code>__enable_if</code>, others.)
 355 </para>
 356
 357 <para> Extensions for policy-based data structures revised. New includes,
 358 types, namespace moved to <code>__pb_ds</code>.
 359 </para>
 360
 361 <para> Extensions for debug mode modified: now nested in <code>namespace
 362 std::__debug</code> and extensions in <code>namespace
 363 __gnu_cxx::__debug</code>.</para>
 364
 365 <para> Extensions added: <filename class="headerfile">&lt;ext/typelist.h&gt;</filename>
 366 and <filename class="headerfile">&lt;ext/throw_allocator.h&gt;</filename>.
 367 </para>
 368
 369 </section>
 370
 371 <section xml:id="api.rel_430"><info><title><constant>4.3</constant></title></info>
 372
 373   <para>
 374   </para>
 375
 376
 377 <para>
 378 C++0X features first appear.
 379 </para>
 380
 381 <para>TR1 <filename class="headerfile">&lt;regex&gt;</filename> and <filename class="headerfile">&lt;cmath&gt;</filename>'s mathematical special function added.
 382 </para>
 383
 384 <para>
 385 Backward include edit.
 386 </para>
 387 <itemizedlist>
 388   <listitem>
 389     <para>Removed</para>
 390   <para>
 391 <filename class="headerfile">&lt;algobase.h&gt;</filename> <filename class="headerfile">&lt;algo.h&gt;</filename> <filename class="headerfile">&lt;alloc.h&gt;</filename> <filename class="headerfile">&lt;bvector.h&gt;</filename> <filename class="headerfile">&lt;complex.h&gt;</filename>
 392 <filename class="headerfile">&lt;defalloc.h&gt;</filename> <filename class="headerfile">&lt;deque.h&gt;</filename> <filename class="headerfile">&lt;fstream.h&gt;</filename> <filename class="headerfile">&lt;function.h&gt;</filename> <filename class="headerfile">&lt;hash_map.h&gt;</filename> <filename class="headerfile">&lt;hash_set.h&gt;</filename>
 393 <filename class="headerfile">&lt;hashtable.h&gt;</filename> <filename class="headerfile">&lt;heap.h&gt;</filename> <filename class="headerfile">&lt;iomanip.h&gt;</filename> <filename class="headerfile">&lt;iostream.h&gt;</filename> <filename class="headerfile">&lt;istream.h&gt;</filename> <filename class="headerfile">&lt;iterator.h&gt;</filename>
 394 <filename class="headerfile">&lt;list.h&gt;</filename> <filename class="headerfile">&lt;map.h&gt;</filename> <filename class="headerfile">&lt;multimap.h&gt;</filename> <filename class="headerfile">&lt;multiset.h&gt;</filename> <filename class="headerfile">&lt;new.h&gt;</filename> <filename class="headerfile">&lt;ostream.h&gt;</filename> <filename class="headerfile">&lt;pair.h&gt;</filename> <filename class="headerfile">&lt;queue.h&gt;</filename> <filename class="headerfile">&lt;rope.h&gt;</filename> <filename class="headerfile">&lt;set.h&gt;</filename> <filename class="headerfile">&lt;slist.h&gt;</filename> <filename class="headerfile">&lt;stack.h&gt;</filename> <filename class="headerfile">&lt;streambuf.h&gt;</filename> <filename class="headerfile">&lt;stream.h&gt;</filename> <filename class="headerfile">&lt;tempbuf.h&gt;</filename>
 395 <filename class="headerfile">&lt;tree.h&gt;</filename> <filename class="headerfile">&lt;vector.h&gt;</filename>
 396   </para>
 397   </listitem>
 398   <listitem>
 399     <para>Added</para>
 400   <para>
 401   <filename class="headerfile">&lt;hash_map&gt;</filename> and <filename class="headerfile">&lt;hash_set&gt;</filename>
 402   </para>
 403   </listitem>
 404   <listitem>
 405     <para>Added in C++11</para>
 406   <para>
 407     <filename class="headerfile">&lt;auto_ptr.h&gt;</filename> and <filename class="headerfile">&lt;binders.h&gt;</filename>
 408   </para>
 409   </listitem>
 410
 411 </itemizedlist>
 412
 413 <para>
 414 Header dependency streamlining.
 415 </para>
 416
 417 <itemizedlist>
 418   <listitem><para><filename class="headerfile">&lt;algorithm&gt;</filename> no longer includes <filename class="headerfile">&lt;climits&gt;</filename>, <filename class="headerfile">&lt;cstring&gt;</filename>, or <filename class="headerfile">&lt;iosfwd&gt;</filename> </para></listitem>
 419   <listitem><para><filename class="headerfile">&lt;bitset&gt;</filename> no longer includes <filename class="headerfile">&lt;istream&gt;</filename> or <filename class="headerfile">&lt;ostream&gt;</filename>, adds <filename class="headerfile">&lt;iosfwd&gt;</filename> </para></listitem>
 420   <listitem><para><filename class="headerfile">&lt;functional&gt;</filename> no longer includes <filename class="headerfile">&lt;cstddef&gt;</filename></para></listitem>
 421   <listitem><para><filename class="headerfile">&lt;iomanip&gt;</filename> no longer includes <filename class="headerfile">&lt;istream&gt;</filename>, <filename class="headerfile">&lt;istream&gt;</filename>, or <filename class="headerfile">&lt;functional&gt;</filename>, adds <filename class="headerfile">&lt;ioswd&gt;</filename> </para></listitem>
 422   <listitem><para><filename class="headerfile">&lt;numeric&gt;</filename> no longer includes <filename class="headerfile">&lt;iterator&gt;</filename></para></listitem>
 423   <listitem><para><filename class="headerfile">&lt;string&gt;</filename> no longer includes <filename class="headerfile">&lt;algorithm&gt;</filename> or <filename class="headerfile">&lt;memory&gt;</filename></para></listitem>
 424
 425   <listitem><para><filename class="headerfile">&lt;valarray&gt;</filename> no longer includes <filename class="headerfile">&lt;numeric&gt;</filename> or <filename class="headerfile">&lt;cstdlib&gt;</filename></para></listitem>
 426   <listitem><para><filename class="headerfile">&lt;tr1/hashtable&gt;</filename> no longer includes <filename class="headerfile">&lt;memory&gt;</filename> or <filename class="headerfile">&lt;functional&gt;</filename></para></listitem>
 427   <listitem><para><filename class="headerfile">&lt;tr1/memory&gt;</filename> no longer includes <filename class="headerfile">&lt;algorithm&gt;</filename></para></listitem>
 428   <listitem><para><filename class="headerfile">&lt;tr1/random&gt;</filename> no longer includes <filename class="headerfile">&lt;algorithm&gt;</filename> or <filename class="headerfile">&lt;fstream&gt;</filename></para></listitem>
 429 </itemizedlist>
 430
 431 <para>
 432 Debug mode for <filename class="headerfile">&lt;unordered_map&gt;</filename> and <filename class="headerfile">&lt;unordered_set&gt;</filename>.
 433 </para>
 434
 435 <para>
 436 Parallel mode first appears.
 437 </para>
 438
 439 <para>Variadic template implementations of items in <filename class="headerfile">&lt;tuple&gt;</filename> and
 440     <filename class="headerfile">&lt;functional&gt;</filename>.
 441 </para>
 442
 443 <para>Default <code>what</code> implementations give more elaborate
 444     exception strings for <code>bad_cast</code>,
 445     <code>bad_typeid</code>, <code>bad_exception</code>, and
 446     <code>bad_alloc</code>.
 447 </para>
 448
 449 <para>
 450 PCH binary files no longer installed. Instead, the source files are installed.
 451 </para>
 452
 453 <para>
 454 Namespace pb_ds moved to __gnu_pb_ds.
 455 </para>
 456
 457 </section>
 458
 459
 460 <section xml:id="api.rel_440"><info><title><constant>4.4</constant></title></info>
 461
 462   <para>
 463   </para>
 464
 465 <para>
 466 C++0X features.
 467 </para>
 468
 469 <itemizedlist>
 470 <listitem>
 471   <para>
 472     Added.
 473   </para>
 474   <para>
 475     <filename class="headerfile">&lt;atomic&gt;</filename>,
 476     <filename class="headerfile">&lt;chrono&gt;</filename>,
 477     <filename class="headerfile">&lt;condition_variable&gt;</filename>,
 478     <filename class="headerfile">&lt;forward_list&gt;</filename>,
 479     <filename class="headerfile">&lt;initializer_list&gt;</filename>,
 480     <filename class="headerfile">&lt;mutex&gt;</filename>,
 481     <filename class="headerfile">&lt;ratio&gt;</filename>,
 482     <filename class="headerfile">&lt;thread&gt;</filename>
 483   </para>
 484 </listitem>
 485
 486 <listitem>
 487   <para>
 488     Updated and improved.
 489   </para>
 490   <para>
 491     <filename class="headerfile">&lt;algorithm&gt;</filename>,
 492     <filename class="headerfile">&lt;system_error&gt;</filename>,
 493     <filename class="headerfile">&lt;type_traits&gt;</filename>
 494   </para>
 495 </listitem>
 496
 497 <listitem>
 498   <para>
 499     Use of the GNU extension namespace association converted to inline namespaces.
 500   </para>
 501 </listitem>
 502
 503 <listitem>
 504   <para>
 505     Preliminary support for <classname>initializer_list</classname>
 506     and defaulted and deleted constructors in container classes.
 507   </para>
 508 </listitem>
 509
 510 <listitem>
 511   <para>
 512     <classname>unique_ptr</classname>.
 513   </para>
 514 </listitem>
 515
 516 <listitem>
 517   <para>
 518     Support for new character types <type>char16_t</type>
 519     and <type>char32_t</type> added
 520     to <classname>char_traits</classname>, <classname>basic_string</classname>, <classname>numeric_limits</classname>,
 521     and assorted compile-time type traits.
 522   </para>
 523 </listitem>
 524
 525 <listitem>
 526   <para>
 527     Support for string conversions <function>to_string</function>
 528     and <function>to_wstring</function>.
 529   </para>
 530 </listitem>
 531
 532 <listitem>
 533   <para>
 534     Member functions taking string arguments were added to iostreams
 535     including <classname>basic_filebuf</classname>, <classname>basic_ofstream</classname>,
 536     and <classname>basic_ifstream</classname>.
 537   </para>
 538 </listitem>
 539
 540 <listitem>
 541   <para>
 542     Exception propagation support,
 543     including <classname>exception_ptr</classname>, <function>current_exception</function>, <function>copy_exception</function>,
 544     and <function>rethrow_exception</function>.
 545   </para>
 546 </listitem>
 547 </itemizedlist>
 548
 549
 550   <para>
 551 Uglification of <literal>try</literal> to <literal>__try</literal>
 552 and <literal>catch</literal> to <literal>__catch</literal>.
 553   </para>
 554
 555   <para>
 556 Audit of internal mutex usage, conversion to functions returning static
 557 local mutex.
 558   </para>
 559
 560 <para> Extensions
 561 added: <filename class="headerfile">&lt;ext/pointer.h&gt;</filename>
 562 and <filename class="headerfile">&lt;ext/extptr_allocator.h&gt;</filename>. Support
 563 for non-standard pointer types has been added
 564 to <classname>vector</classname>
 565 and <classname>forward_list</classname>.
 566 </para>
 567 </section>
 568
 569 <section xml:id="api.rel_450"><info><title><constant>4.5</constant></title></info>
 570
 571   <para>
 572   </para>
 573
 574 <para>
 575 C++0X features.
 576 </para>
 577
 578 <itemizedlist>
 579 <listitem>
 580   <para>
 581     Added.
 582   </para>
 583   <para>
 584     <filename class="headerfile">&lt;functional&gt;</filename>,
 585     <filename class="headerfile">&lt;future&gt;</filename>,
 586     <filename class="headerfile">&lt;random&gt;</filename>
 587   </para>
 588 </listitem>
 589
 590 <listitem>
 591   <para>
 592     Updated and improved.
 593   </para>
 594   <para>
 595     <filename class="headerfile">&lt;atomic&gt;</filename>,
 596     <filename class="headerfile">&lt;system_error&gt;</filename>,
 597     <filename class="headerfile">&lt;type_traits&gt;</filename>
 598   </para>
 599 </listitem>
 600
 601 <listitem>
 602   <para>
 603     Add support for explicit operators and standard layout types.
 604   </para>
 605 </listitem>
 606 </itemizedlist>
 607
 608 <para>
 609 Profile mode first appears.
 610 </para>
 611
 612 <para>
 613 Support for decimal floating-point arithmetic, including <classname>decimal32</classname>, <classname>decimal64</classname>, and <classname>decimal128</classname>.
 614 </para>
 615
 616 <para>
 617 Python pretty-printers are added for use with appropriately-advanced versions of <command>gdb</command>.
 618 </para>
 619
 620 <para>
 621 Audit for application of function attributes nothrow, const, pure, and noreturn.
 622 </para>
 623
 624 <para>
 625 The default behavior for comparing typeinfo names changed, so
 626 in <filename class="headerfile">&lt;typeinfo&gt;</filename>, <literal>__GXX_MERGED_TYPEINFO_NAMES</literal>
 627 now defaults to zero.
 628 </para>
 629
 630 <para> Extensions modified: <filename class="headerfile">&lt;ext/throw_allocator.h&gt;</filename>.
 631 </para>
 632 </section>
 633
 634 <section xml:id="api.rel_460"><info><title><constant>4.6</constant></title></info>
 635
 636 <para>
 637   Use constexpr and nullptr where appropriate throughout the library.
 638 </para>
 639
 640 <para>
 641   The library was updated to avoid including
 642   <filename class="headerfile">&lt;stddef.h&gt;</filename> in order
 643   to reduce namespace pollution.
 644 </para>
 645
 646 <para>Reference-count annotations to assist data race detectors.
 647 </para>
 648
 649 <para>
 650   Added <function>make_exception_ptr</function> as an alias of
 651   <function>copy_exception</function>.
 652 </para>
 653
 654 </section>
 655
 656 <section xml:id="api.rel_470"><info><title><constant>4.7</constant></title></info>
 657
 658 <para>Use of noexcept throughout library.</para>
 659
 660 <para>Partial support for C++11 allocators first appears.</para>
 661
 662 <para>
 663   <classname>monotonic_clock</classname> renamed to
 664   <classname>steady_clock</classname> as required by the final C++11
 665   standard.
 666 </para>
 667
 668 <para>A new clocale model for newlib is available.</para>
 669
 670 <para>
 671   The library was updated to avoid including
 672   <filename class="headerfile">&lt;unistd.h&gt;</filename> in order
 673   to reduce namespace pollution.
 674 </para>
 675
 676 <para>Debug Mode was improved for unordered containers. </para>
 677
 678 </section>
 679
 680 <section xml:id="api.rel_480"><info><title><constant>4.8</constant></title></info>
 681
 682 <para>
 683   New random number engines and distributions.
 684   Optimisations for random.
 685 </para>
 686
 687 <para>New --enable-libstdcxx-verbose configure option</para>
 688
 689 <para>
 690   The --enable-libstdcxx-time configure option becomes unnecessary given a
 691   sufficiently recent glibc.
 692 </para>
 693
 694 </section>
 695
 696 <section xml:id="api.rel_490"><info><title><constant>4.9</constant></title></info>
 697
 698 <para> Implementation of <classname>regex</classname> completed. </para>
 699
 700 <para> C++14 library and TS implementations are added. </para>
 701
 702 <para> <function>copy_exception</function> deprecated. </para>
 703
 704 <para> <classname>__gnu_cxx::array_allocator</classname> deprecated. </para>
 705
 706 </section>
 707
 708 <section xml:id="api.rel_51"><info><title><constant>5</constant></title></info>
 709
 710 <para>
 711   ABI transition adds new implementations of several components, using the
 712   <code>abi_tag</code> attribute and the <code>__cxx11</code> inline
 713   namespace to distinguish the new entities from the old ones.
 714 </para>
 715
 716 <itemizedlist>
 717 <listitem>
 718   <para>
 719     Use of the new or old ABI can be selected per-translation unit with the
 720     <xref linkend="manual.intro.using.macros"><symbol>_GLIBCXX_USE_CXX11_ABI</symbol>
 721     macro</xref>.
 722   </para>
 723 </listitem>
 724 <listitem>
 725   <para>
 726     New non-reference-counted <classname>string</classname> implementation.
 727   </para>
 728 </listitem>
 729 <listitem>
 730   <para>
 731     New <classname>list</classname> implementation containing a new
 732     data member in order to provide O(1) <function>size()</function>.
 733   </para>
 734 </listitem>
 735 <listitem>
 736   <para>
 737     New <classname>ios_base::failure</classname> implementation inheriting
 738     from <classname>system_error</classname>.
 739   </para>
 740 </listitem>
 741 </itemizedlist>
 742
 743 <para>
 744   C++11 support completed (movable iostreams, new I/O manipulators,
 745   Unicode conversion utilities, atomic operations for
 746   <classname>shared_ptr</classname>, functions for notifying condition
 747   variables and making futures ready at thread exit).
 748 </para>
 749
 750 <para>
 751    Changed formatting of floating point types when
 752    <code>ios_base::fixed|ios_base::scientific</code> is set in a stream's
 753    format flags.
 754 </para>
 755
 756 <para> Improved C++14 support and TS implementations. </para>
 757
 758 <para> New random number engines and distributions. </para>
 759
 760 <para>
 761   GDB Xmethods for containers and <classname>unique_ptr</classname> added.
 762 </para>
 763
 764 <para>
 765   <classname>has_trivial_default_constructor</classname>,
 766   <classname>has_trivial_copy_constructor</classname> and
 767   <classname>has_trivial_copy_assign</classname> deprecated.
 768 </para>
 769
 770 <section xml:id="api.rel_53"><info><title><constant>5.3</constant></title></info>
 771 <para> Experimental implementation of the C++ Filesystem TS added. </para>
 772
 773 </section>
 774
 775 </section>
 776
 777 <section xml:id="api.rel_61"><info><title><constant>6</constant></title></info>
 778
 779 <para> C++14 support completed. </para>
 780
 781 <para>
 782   Support for mathematical special functions (ISO/IEC 29124:2010) added.
 783 </para>
 784
 785 <para>
 786   Assertions to check function preconditions can be enabled by defining the
 787   <link linkend="manual.intro.using.macros"><symbol>_GLIBCXX_ASSERTIONS</symbol>
 788   macro</link>.
 789   The initial set of assertions are a subset of the checks enabled by
 790   the Debug Mode, but without the ABI changes and changes to algorithmic
 791   complexity that are caused by enabling the full Debug Mode.
 792 </para>
 793
 794 </section>
 795
 796 <section xml:id="api.rel_71"><info><title><constant>7</constant></title></info>
 797
 798 <para>
 799   The type of exception thrown by iostreams changed to the <code>cxx11</code>
 800   ABI version of <classname>std::ios_base::failure</classname>.
 801 </para>
 802
 803 <para>
 804   Experimental C++17 support added, including most new library features.
 805   The meaning of <classname>shared_ptr&lt;T[]&gt;</classname> changed to
 806   match the C++17 semantics.
 807 </para>
 808
 809 <para>
 810   <xref linkend="manual.intro.using.macros"><symbol>_GLIBCXX_RELEASE</symbol>
 811   macro</xref> added.
 812 </para>
 813
 814 <para>
 815   <classname>has_trivial_default_constructor</classname>,
 816   <classname>has_trivial_copy_constructor</classname> and
 817   <classname>has_trivial_copy_assign</classname> removed.
 818 </para>
 819
 820 <para>
 821 Calling a <code>std::bind</code> result as volatile was deprecated for C++17.
 822 </para>
 823
 824 <para> Profile Mode was deprecated. </para>
 825
 826 <section xml:id="api.rel_72"><info><title><constant>7.2</constant></title></info>
 827
 828 <para>
 829   Library Fundamentals TS header
 830   <filename class="headerfile">&lt;experimental/source_location&gt;</filename>
 831   added.
 832 </para>
 833
 834 </section>
 835
 836 <section xml:id="api.rel_73"><info><title><constant>7.3</constant></title></info>
 837
 838 <para>
 839   Including new C++14 or C++17 headers without a suitable <option>-std</option>
 840   no longer causes compilation to fail via <literal>#error</literal>.
 841   Instead the header is simply empty and doesn't define anything.
 842 </para>
 843
 844 </section>
 845
 846 </section>
 847
 848 <section xml:id="api.rel_81"><info><title><constant>8</constant></title></info>
 849
 850 <para>
 851   The exceptions thrown by iostreams can now be caught by handlers for either
 852   version of <classname>std::ios_base::failure</classname>.
 853 </para>
 854
 855 <para>
 856   Improved experimental C++17 support. Headers
 857   <filename class="headerfile">&lt;charconv&gt;</filename> and
 858   <filename class="headerfile">&lt;filesystem&gt;</filename>.
 859   Experimental implementation of the C++17 Filesystem library added.
 860 </para>
 861
 862 <para>
 863   Experimental C++2a support
 864   (<function>to_address</function> and <classname>endian</classname>).
 865 </para>
 866
 867 <para>
 868   AddressSanitizer annotations added to <classname>std::vector</classname>
 869   to detect out-of-range accesses to the unused capacity of a vector.
 870 </para>
 871
 872 <para>
 873   <function>std::char_traits&lt;char16_t&gt;::to_int_type(u'\uFFFF')</function>
 874   now returns <literal>0xFFFD</literal>, as <literal>0xFFFF</literal> is
 875   used for <function>std::char_traits&lt;char16_t&gt;::eof()</function>.
 876 </para>
 877
 878 <para>
 879   The extension allowing arithmetic on
 880   <classname>std::atomic&lt;void*&gt;</classname> and types like
 881   <classname>std::atomic&lt;R(*)()&gt;</classname> was deprecated.
 882 </para>
 883
 884 <para>
 885   The <function>std::uncaught_exception</function> function was deprecated
 886   for C++17 mode.
 887 </para>
 888
 889 <para>
 890   The nested typedefs <type>std::hash::result_type</type> and
 891   <type>std::hash::argument_type</type> were deprecated for C++17 mode.
 892 </para>
 893
 894 <para>
 895   The deprecated iostream members <type>ios_base::io_state</type>,
 896   <type>ios_base::open_mode</type>, <type>ios_base::seek_dir</type>, and
 897   <function>basic_streambuf::stossc</function> were removed for C++17 mode.
 898 </para>
 899
 900 <para>
 901   The non-standard C++0x <function>std::copy_exception</function> function
 902   was removed.
 903 </para>
 904
 905 <para>
 906   For <option>-std=c++11</option>, <option>-std=c++14</option>, and
 907   <option>-std=c++17</option> modes the <filename>&lt;complex.h&gt;</filename>
 908   header no longer includes the C99 <filename>&lt;complex.h&gt;</filename>
 909   header.
 910 </para>
 911
 912 <para>
 913   For the non-default <option>--enable-symvers=gnu-versioned-namespace</option>
 914   configuration, the shared library SONAME has been changed to
 915   <filename>libstdc++.so.8</filename>.
 916 </para>
 917
 918 <para>
 919   The extension allowing containers to be instantiated with an allocator
 920   that doesn't match the container's value type is no longer allowed in
 921   strict (<option>-std=c++NN</option>) modes, only in
 922   <option>-std=gnu++NN</option> modes.
 923 </para>
 924
 925 </section>
 926
 927 <section xml:id="api.rel_91"><info><title><constant>9</constant></title></info>
 928
 929 <para>
 930   C++17 header
 931   <filename class="headerfile">&lt;memory_resource&gt;</filename>
 932   added.
 933 </para>
 934
 935 <para>
 936   Experimental C++2a support improved, with new headers
 937   <filename class="headerfile">&lt;bit&gt;</filename> and
 938   <filename class="headerfile">&lt;version&gt;</filename> added.
 939   Support for new character type <type>char8_t</type> added
 940   to <classname>char_traits</classname>, <classname>basic_string</classname>,
 941   <classname>numeric_limits</classname>,
 942   and relevant locale facets and type traits.
 943 </para>
 944
 945 <para>
 946   Experimental implementation of the Networking TS library added,
 947   with new headers
 948   <filename class="headerfile">&lt;experimental/buffer&gt;</filename>,
 949   <filename class="headerfile">&lt;experimental/executor&gt;</filename>,
 950   <filename class="headerfile">&lt;experimental/internet&gt;</filename>,
 951   <filename class="headerfile">&lt;experimental/io_context&gt;</filename>,
 952   <filename class="headerfile">&lt;experimental/net&gt;</filename>,
 953   <filename class="headerfile">&lt;experimental/netfwd&gt;</filename>,
 954   <filename class="headerfile">&lt;experimental/socket&gt;</filename>,
 955   and
 956   <filename class="headerfile">&lt;experimental/timer&gt;</filename>.
 957 </para>
 958
 959 </section>
 960
 961 <section xml:id="api.rel_101"><info><title><constant>10</constant></title></info>
 962 <para> Deprecated features removed:
 963 <itemizedlist>
 964 <listitem> Profile Mode </listitem>
 965 <listitem> <classname>__gnu_cxx::array_allocator</classname> </listitem>
 966 </itemizedlist>
 967 </para>
 968
 969 <para>
 970   The non-standard <function>std::__is_nullptr_t</function> type trait
 971   was deprecated.
 972 </para>
 973
 974 <para>
 975   The <classname>std::packaged_task</classname> constructors taking
 976   an allocator argument are only defined for C++11 and C++14.
 977 </para>
 978
 979 <para>
 980   Several members of <classname>std::allocator</classname> were removed
 981   for C++20 mode. The removed functionality has been provided by
 982   <classname>std::allocator_traits</classname> since C++11 and that should
 983   be used instead.
 984 </para>
 985
 986 <para>
 987   The type of the <classname>std::iterator</classname> base class of
 988   <classname>std::istreambuf_iterator</classname> was changed to be
 989   consistent for all <option>-std</option> modes.
 990   Before GCC 10.1 the base class had one type in C++98 mode and a
 991   different type in C++11 and later modes. The type in C++98 mode
 992   was changed to be the same as for C++11 and later.
 993 </para>
 994
 995 <para>
 996   Experimental C++2a support improved, with new headers
 997   <filename class="headerfile">&lt;concepts&gt;</filename>,
 998   <filename class="headerfile">&lt;ranges&gt;</filename>,
 999   <filename class="headerfile">&lt;compare&gt;</filename>,
1000   <filename class="headerfile">&lt;coroutine&gt;</filename>,
1001   <filename class="headerfile">&lt;numbers&gt;</filename>,
1002   <filename class="headerfile">&lt;span&gt;</filename>,
1003   and
1004   <filename class="headerfile">&lt;stop_token&gt;</filename>
1005   added.
1006 </para>
1007
1008 <para>
1009   The extension allowing containers to be instantiated with an allocator
1010   that doesn't match the container's value type is no longer allowed in
1011   C++20 mode, even in non-strict <option>-std=gnu++20</option> mode.
1012 </para>
1013
1014 </section>
1015
1016 <section xml:id="api.rel_111"><info><title><constant>11</constant></title></info>
1017
1018 <para>
1019   The <option>--enable-cheaders=c_std</option> configuration
1020   was deprecated.
1021 </para>
1022
1023 <para>
1024   When compiling as C++20, the <function>operator&gt;&gt;</function> overloads
1025   for extracting strings into character buffers only work with arrays,
1026   not raw pointers.
1027 </para>
1028
1029 <para>
1030   <code>std::string::reserve(n)</code> will no longer reduce
1031   the string's capacity.
1032   Calling <function>reserve()</function> with no arguments is equivalent
1033   to <function>shrink_to_fit()</function>, but is deprecated.
1034   <function>shrink_to_fit()</function> should be used instead.
1035 </para>
1036
1037 </section>
1038
1039 <section xml:id="api.rel_121"><info><title><constant>12</constant></title></info>
1040
1041 <para>
1042 The <function>std::random_shuffle</function> algorithms are deprecated
1043 for C++14 and later. The C++11 <function>std::shuffle</function> algorithm
1044 can be used instead.
1045 </para>
1046
1047 <para>
1048 The <function>std::unexpected</function> function and related typedef and
1049 accessors for the unexpected handler are deprecated for C++11 and later.
1050 Dynamic exception specifications should be replaced with <code>noexcept</code>.
1051 </para>
1052
1053 <para>
1054 C++98 adaptable function utilities
1055 (<code>std::bind1st</code>, <code>std::unary_function</code>,
1056 <code>std::ptr_fun</code>, <code>std::mem_fun_ref</code> etc.)
1057 were deprecated for C++11.
1058 <code>std::iterator</code>, <code>std::raw_storage_iterator</code>,
1059 <code>get_temporary_buffer</code>, and <code>std::not_fun</code>
1060 were deprecated for C++17.
1061 </para>
1062
1063 <para>
1064 Non-standard <code>std::pair</code> constructors were deprecated.
1065 A non-standard default argument for
1066 <code>vector&lt;bool&gt;::insert(const_iterator, const bool&amp;)</code>
1067 was deprecated.
1068 </para>
1069
1070 <para>
1071 The <literal>bitmap</literal>, <literal>mt</literal>, and <literal>pool</literal>
1072 options for <option>--enable-libstdcxx-allocator</option> were removed.
1073 For the <literal>new</literal> option, <classname>std::allocator</classname>
1074 no longer derives from <classname>__gnu_cxx::new_allocator</classname>;
1075 they both derive from <classname>std::__new_allocator</classname> instead.
1076 </para>
1077
1078 <para>
1079 <function>std::condition_variable::wait</function> changed to be
1080 <code>noexcept(false)</code> to allow thread cancellation exceptions to
1081 be thrown from <function>pthread_cond_wait</function> without aborting
1082 the process.
1083 </para>
1084
1085 </section>
1086
1087
1088 <section xml:id="api.rel_123"><info><title><constant>12.3</constant></title></info>
1089 <para>
1090 Calling a <code>std::bind</code> result as volatile is ill-formed for C++20
1091 and later.
1092 </para>
1093
1094 </section>
1095
1096 <section xml:id="api.rel_131"><info><title><constant>13</constant></title></info>
1097
1098 <para>
1099 Tunables <variable>glibcxx.eh_pool.obj_count</variable> and
1100 <variable>glibcxx.eh_pool.obj_size</variable> were added.
1101 </para>
1102
1103 <para>Static library <filename>libstdc++exp.a</filename> was added
1104 to provide the symbols for the experimental C++ Contracts support.</para>
1105
1106 </section>
1107
1108 <section xml:id="api.rel_133"><info><title><constant>13.3</constant></title></info>
1109
1110 <para>
1111 Symbols for the Filesystem TS and C++23 <filename>&lt;stacktrace&gt;</filename>
1112 header were added to the static library <filename>libstdc++exp.a</filename>.
1113 </para>
1114
1115 </section>
1116
1117 <section xml:id="api.rel_141"><info><title><constant>14</constant></title></info>
1118
1119 <para>
1120 Deprecate the non-standard overload that allows <code>std::setfill</code>
1121 to be used with <code>std::basic_istream</code>.
1122 </para>
1123
1124 <para>
1125   The extension allowing <code>std::basic_string</code> to be instantiated
1126   with an allocator that doesn't match the string's character type is no
1127   longer allowed in C++20 mode.
1128 </para>
1129
1130 </section>
1131
1132 <section xml:id="api.rel_151"><info><title><constant>15</constant></title></info>
1133
1134 <para>
1135 Enabled debug assertions by default for unoptimized builds.
1136 </para>
1137
1138 <para>
1139 Added warnings when including the headers that were deprecated in C++17
1140 and removed in C++20:
1141 <filename class="headerfile">&lt;ccomplex&gt;</filename>,
1142 <filename class="headerfile">&lt;ciso646&gt;</filename>,
1143 <filename class="headerfile">&lt;cstdalign&gt;</filename>,
1144 <filename class="headerfile">&lt;cstdbool&gt;</filename>, and
1145 <filename class="headerfile">&lt;ctgmath&gt;</filename>.
1146 </para>
1147
1148 <para>
1149 Nested <code>result_type</code> and <code>argument_type</code> removed from
1150 <classname>std::hash</classname> specializations for C++20.
1151 </para>
1152
1153 </section>
1154
1155 </section>