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
  17 <para>
  18 A list of user-visible changes, in chronological order
  19 </para>
  20
  21 <section xml:id="api.rel_300"><info><title><constant>3.0</constant></title></info>
  22
  23
  24   <para>
  25 Extensions moved to <filename class="directory">include/ext</filename>.
  26   </para>
  27
  28 <para>
  29 Include files from the SGI/HP sources that pre-date the ISO standard
  30 are added. These files are placed into
  31 the <filename class="directory">include/backward</filename> directory and a deprecated warning
  32 is added that notifies on inclusion (<literal>-Wno-deprecated</literal>
  33 deactivates the warning.)
  34 </para>
  35
  36 <para>Deprecated include <filename class="headerfile">backward/strstream</filename> added.</para>
  37
  38 <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>.
  39 </para>
  40
  41
  42
  43 </section>
  44
  45 <section xml:id="api.rel_310"><info><title><constant>3.1</constant></title></info>
  46
  47   <para>
  48   </para>
  49
  50 <para>
  51 Extensions from SGI/HP moved from <code>namespace std</code>
  52 to <code>namespace __gnu_cxx</code>. As part of this, the following
  53 new includes are
  54 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>.
  55 </para>
  56
  57 <para>
  58 Extensions to <code>basic_filebuf</code> introduced: <code>__gnu_cxx::enc_filebuf</code>, and <code>__gnu_cxx::stdio_filebuf</code>.
  59 </para>
  60
  61 <para>
  62 Extensions to tree data structures added in <filename class="headerfile">ext/rb_tree</filename>.
  63 </para>
  64
  65 <para>
  66 Removal of <filename class="headerfile">ext/tree</filename>, moved to <filename class="headerfile">backward/tree.h</filename>.
  67 </para>
  68
  69 </section>
  70
  71 <section xml:id="api.rel_320"><info><title><constant>3.2</constant></title></info>
  72
  73   <para>
  74   </para>
  75 <para>Symbol versioning introduced for shared library.</para>
  76
  77 <para>Removal of include <filename class="headerfile">backward/strstream.h</filename>.</para>
  78
  79 <para>Allocator changes. Change <code>__malloc_alloc</code> to <code>malloc_allocator</code> and <code>__new_alloc</code> to <code>new_allocator</code>. </para>
  80
  81    <para> For GCC releases from 2.95 through the 3.1 series, defining
  82    <literal>__USE_MALLOC</literal> on the gcc command line would change the
  83    default allocation strategy to instead use <code> malloc</code> and
  84    <function>free</function>. (This same functionality is now spelled <literal>_GLIBCXX_FORCE_NEW</literal>, see
  85    <link linkend="manual.intro.using.macros">this page</link>
  86    for details.
  87    </para>
  88
  89
  90 <para>Error handling in iostreams cleaned up, made consistent. </para>
  91
  92
  93 </section>
  94
  95 <section xml:id="api.rel_330"><info><title><constant>3.3</constant></title></info>
  96
  97   <para>
  98   </para>
  99 </section>
 100
 101 <section xml:id="api.rel_340"><info><title><constant>3.4</constant></title></info>
 102
 103   <para>
 104   </para>
 105 <para>
 106 Large file support.
 107 </para>
 108
 109 <para> Extensions for generic characters and <code>char_traits</code> added in <filename class="headerfile">ext/pod_char_traits.h</filename>.
 110 </para>
 111
 112 <para>
 113 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.
 114 </para>
 115
 116 <para>
 117 Support for <code>char_traits</code> beyond builtin types.
 118 </para>
 119
 120 <para>
 121 Conformant <code>allocator</code> class and usage in containers. As
 122 part of this, the following extensions are
 123 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>.
 124 </para>
 125
 126 <para>
 127 This is a change from all previous versions, and may require
 128 source-level changes due to allocator-related changes to structures
 129 names and template parameters, filenames, and file locations. Some,
 130 like <code>__simple_alloc, __allocator, __alloc, </code> and <code>
 131 _Alloc_traits</code> have been removed.
 132 </para>
 133
 134 <para>Default behavior of <code>std::allocator</code> has changed.</para>
 135
 136 <para>
 137    Previous versions prior to 3.4 cache allocations in a memory
 138    pool, instead of passing through to call the global allocation
 139    operators (i.e., <classname>__gnu_cxx::pool_allocator</classname>).  More
 140    recent versions default to the
 141    simpler <classname>__gnu_cxx::new_allocator</classname>.
 142 </para>
 143
 144 <para> Previously, all allocators were written to the SGI
 145    style, and all STL containers expected this interface. This
 146    interface had a traits class called <code>_Alloc_traits</code> that
 147    attempted to provide more information for compile-time allocation
 148    selection and optimization. This traits class had another allocator
 149    wrapper, <code>__simple_alloc&lt;T,A&gt;</code>, which was a
 150    wrapper around another allocator, A, which itself is an allocator
 151    for instances of T. But wait, there's more:
 152    <code>__allocator&lt;T,A&gt;</code> is another adapter.  Many of
 153    the provided allocator classes were SGI style: such classes can be
 154    changed to a conforming interface with this wrapper:
 155    <code>__allocator&lt;T, __alloc&gt;</code> is thus the same as
 156    <code>allocator&lt;T&gt;</code>.
 157    </para>
 158
 159    <para> The class <classname>allocator</classname> used the typedef
 160    <type>__alloc</type> to select an underlying allocator that
 161    satisfied memory allocation requests. The selection of this
 162    underlying allocator was not user-configurable.
 163    </para>
 164
 165 <table frame="all">
 166 <title>Extension Allocators</title>
 167
 168 <tgroup cols="4" align="left" colsep="1" rowsep="1">
 169 <colspec colname="c1"/>
 170 <colspec colname="c2"/>
 171 <colspec colname="c3"/>
 172 <colspec colname="c4"/>
 173
 174   <thead>
 175     <row>
 176       <entry>Allocator (3.4)</entry>
 177       <entry>Header (3.4)</entry>
 178       <entry>Allocator (3.[0-3])</entry>
 179       <entry>Header (3.[0-3])</entry>
 180     </row>
 181   </thead>
 182
 183   <tbody>
 184   <row>
 185     <entry><classname>__gnu_cxx::new_allocator&lt;T&gt;</classname></entry>
 186     <entry><filename class="headerfile">ext/new_allocator.h</filename></entry>
 187     <entry><classname>std::__new_alloc</classname></entry>
 188     <entry><filename class="headerfile">memory</filename></entry>
 189   </row>
 190   <row>
 191     <entry><classname>__gnu_cxx::malloc_allocator&lt;T&gt;</classname></entry>
 192     <entry><filename class="headerfile">ext/malloc_allocator.h</filename></entry>
 193     <entry><classname>std::__malloc_alloc_template&lt;int&gt;</classname></entry>
 194     <entry><filename class="headerfile">memory</filename></entry>
 195   </row>
 196   <row>
 197     <entry><classname>__gnu_cxx::debug_allocator&lt;T&gt;</classname></entry>
 198     <entry><filename class="headerfile">ext/debug_allocator.h</filename></entry>
 199     <entry><classname>std::debug_alloc&lt;T&gt;</classname></entry>
 200     <entry><filename class="headerfile">memory</filename></entry>
 201   </row>
 202   <row>
 203     <entry><classname>__gnu_cxx::__pool_alloc&lt;T&gt;</classname></entry>
 204     <entry><filename class="headerfile">ext/pool_allocator.h</filename></entry>
 205     <entry><classname>std::__default_alloc_template&lt;bool,int&gt;</classname></entry>
 206     <entry><filename class="headerfile">memory</filename></entry>
 207   </row>
 208   <row>
 209     <entry><classname>__gnu_cxx::__mt_alloc&lt;T&gt;</classname></entry>
 210     <entry><filename class="headerfile">ext/mt_allocator.h</filename></entry>
 211     <entry> </entry>
 212     <entry> </entry>
 213   </row>
 214   <row>
 215     <entry><classname>__gnu_cxx::bitmap_allocator&lt;T&gt;</classname></entry>
 216     <entry><filename class="headerfile">ext/bitmap_allocator.h</filename></entry>
 217     <entry> </entry>
 218     <entry> </entry>
 219   </row>
 220   </tbody>
 221 </tgroup>
 222 </table>
 223
 224    <para> Releases after gcc-3.4 have continued to add to the collection
 225    of available allocators. All of these new allocators are
 226    standard-style. The following table includes details, along with
 227    the first released version of GCC that included the extension allocator.
 228    </para>
 229
 230 <table frame="all">
 231 <title>Extension Allocators Continued</title>
 232
 233 <tgroup cols="3" align="left" colsep="1" rowsep="1">
 234 <colspec colname="c1"/>
 235 <colspec colname="c2"/>
 236 <colspec colname="c3"/>
 237
 238 <thead>
 239   <row>
 240     <entry>Allocator</entry>
 241     <entry>Include</entry>
 242     <entry>Version</entry>
 243   </row>
 244 </thead>
 245
 246 <tbody>
 247   <row>
 248     <entry><classname>__gnu_cxx::array_allocator&lt;T&gt;</classname></entry>
 249     <entry><filename class="headerfile">ext/array_allocator.h</filename></entry>
 250     <entry>4.0.0</entry>
 251   </row>
 252   <row>
 253     <entry><classname>__gnu_cxx::throw_allocator&lt;T&gt;</classname></entry>
 254     <entry><filename class="headerfile">ext/throw_allocator.h</filename></entry>
 255     <entry>4.2.0</entry>
 256   </row>
 257 </tbody>
 258 </tgroup>
 259 </table>
 260
 261
 262 <para>
 263 Debug mode first appears.
 264 </para>
 265
 266 <para>
 267 Precompiled header support <acronym>PCH</acronym> support.
 268 </para>
 269
 270 <para>
 271 Macro guard for changed, from <literal>_GLIBCPP_</literal> to <literal>_GLIBCXX_</literal>.
 272 </para>
 273
 274 <para>
 275 Extension <filename class="headerfile">ext/stdio_sync_filebuf.h</filename> added.
 276 </para>
 277
 278 <para>
 279 Extension <filename class="headerfile">ext/demangle.h</filename> added.
 280 </para>
 281
 282
 283 </section>
 284
 285 <section xml:id="api.rel_400"><info><title><constant>4.0</constant></title></info>
 286
 287   <para>
 288   </para>
 289 <para>
 290 TR1 features first appear.
 291 </para>
 292
 293 <para>
 294 Extension allocator <filename class="headerfile">ext/array_allocator.h</filename> added.
 295 </para>
 296
 297 <para>
 298 Extension <code>codecvt</code> specializations moved to <filename class="headerfile">ext/codecvt_specializations.h</filename>.
 299 </para>
 300
 301 <para>
 302 Removal of <filename class="headerfile">ext/demangle.h</filename>.
 303 </para>
 304
 305
 306 </section>
 307
 308 <section xml:id="api.rel_410"><info><title><constant>4.1</constant></title></info>
 309
 310   <para>
 311   </para>
 312
 313
 314 <para>
 315 Removal of <filename class="headerfile">cassert</filename> from all standard headers: now has to be explicitly included for <code>std::assert</code> calls.
 316 </para>
 317
 318 <para> Extensions for policy-based data structures first added. New includes,
 319 types, namespace <code>pb_assoc</code>.
 320 </para>
 321
 322
 323
 324 <para> Extensions for typelists added in <filename class="headerfile">ext/typelist.h</filename>.
 325 </para>
 326
 327 <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>.
 328 </para>
 329
 330 </section>
 331
 332 <section xml:id="api.rel_420"><info><title><constant>4.2</constant></title></info>
 333
 334   <para>
 335   </para>
 336
 337
 338 <para> Default visibility attributes applied to <code>namespace std</code>. Support for <code>-fvisibility</code>.
 339 </para>
 340
 341 <para>TR1 <filename class="headerfile">random</filename>, <filename class="headerfile">complex</filename>, and C compatibility headers added.</para>
 342
 343 <para> Extensions for concurrent programming consolidated
 344 into <filename class="headerfile">ext/concurrence.h</filename> and <filename class="headerfile">ext/atomicity.h</filename>,
 345 including change of namespace to <code>__gnu_cxx</code> in some
 346 cases. Added types
 347 include <code>_Lock_policy</code>, <code>__concurrence_lock_error</code>, <code>__concurrence_unlock_error</code>, <code>__mutex</code>, <code>__scoped_lock</code>.</para>
 348
 349 <para> Extensions for type traits consolidated
 350 into <filename class="headerfile">ext/type_traits.h</filename>. Additional traits are added
 351 (<code>__conditional_type</code>, <code>__enable_if</code>, others.)
 352 </para>
 353
 354 <para> Extensions for policy-based data structures revised. New includes,
 355 types, namespace moved to <code>__pb_ds</code>.
 356 </para>
 357
 358 <para> Extensions for debug mode modified: now nested in <code>namespace
 359 std::__debug</code> and extensions in <code>namespace
 360 __gnu_cxx::__debug</code>.</para>
 361
 362 <para> Extensions added: <filename class="headerfile">ext/typelist.h</filename>
 363 and <filename class="headerfile">ext/throw_allocator.h</filename>.
 364 </para>
 365
 366 </section>
 367
 368 <section xml:id="api.rel_430"><info><title><constant>4.3</constant></title></info>
 369
 370   <para>
 371   </para>
 372
 373
 374 <para>
 375 C++0X features first appear.
 376 </para>
 377
 378 <para>TR1 <filename class="headerfile">regex</filename> and <filename class="headerfile">cmath</filename>'s mathematical special function added.
 379 </para>
 380
 381 <para>
 382 Backward include edit.
 383 </para>
 384 <itemizedlist>
 385   <listitem>
 386     <para>Removed</para>
 387   <para>
 388 <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>
 389 <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>
 390 <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>
 391 <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>
 392 <filename class="headerfile">tree.h</filename> <filename class="headerfile">vector.h</filename>
 393   </para>
 394   </listitem>
 395   <listitem>
 396     <para>Added</para>
 397   <para>
 398   <filename class="headerfile">hash_map</filename> and <filename class="headerfile">hash_set</filename>
 399   </para>
 400   </listitem>
 401   <listitem>
 402     <para>Added in C++11</para>
 403   <para>
 404     <filename class="headerfile">auto_ptr.h</filename> and <filename class="headerfile">binders.h</filename>
 405   </para>
 406   </listitem>
 407
 408 </itemizedlist>
 409
 410 <para>
 411 Header dependency streamlining.
 412 </para>
 413
 414 <itemizedlist>
 415   <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>
 416   <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>
 417   <listitem><para><filename class="headerfile">functional</filename> no longer includes <filename class="headerfile">cstddef</filename></para></listitem>
 418   <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>
 419   <listitem><para><filename class="headerfile">numeric</filename> no longer includes <filename class="headerfile">iterator</filename></para></listitem>
 420   <listitem><para><filename class="headerfile">string</filename> no longer includes <filename class="headerfile">algorithm</filename> or <filename class="headerfile">memory</filename></para></listitem>
 421
 422   <listitem><para><filename class="headerfile">valarray</filename> no longer includes <filename class="headerfile">numeric</filename> or <filename class="headerfile">cstdlib</filename></para></listitem>
 423   <listitem><para><filename class="headerfile">tr1/hashtable</filename> no longer includes <filename class="headerfile">memory</filename> or <filename class="headerfile">functional</filename></para></listitem>
 424   <listitem><para><filename class="headerfile">tr1/memory</filename> no longer includes <filename class="headerfile">algorithm</filename></para></listitem>
 425   <listitem><para><filename class="headerfile">tr1/random</filename> no longer includes <filename class="headerfile">algorithm</filename> or <filename class="headerfile">fstream</filename></para></listitem>
 426 </itemizedlist>
 427
 428 <para>
 429 Debug mode for <filename class="headerfile">unordered_map</filename> and <filename class="headerfile">unordered_set</filename>.
 430 </para>
 431
 432 <para>
 433 Parallel mode first appears.
 434 </para>
 435
 436 <para>Variadic template implementations of items in <filename class="headerfile">tuple</filename> and
 437     <filename class="headerfile">functional</filename>.
 438 </para>
 439
 440 <para>Default <code>what</code> implementations give more elaborate
 441     exception strings for <code>bad_cast</code>,
 442     <code>bad_typeid</code>, <code>bad_exception</code>, and
 443     <code>bad_alloc</code>.
 444 </para>
 445
 446 <para>
 447 PCH binary files no longer installed. Instead, the source files are installed.
 448 </para>
 449
 450 <para>
 451 Namespace pb_ds moved to __gnu_pb_ds.
 452 </para>
 453
 454 </section>
 455
 456
 457 <section xml:id="api.rel_440"><info><title><constant>4.4</constant></title></info>
 458
 459   <para>
 460   </para>
 461
 462 <para>
 463 C++0X features.
 464 </para>
 465
 466 <itemizedlist>
 467 <listitem>
 468   <para>
 469     Added.
 470   </para>
 471   <para>
 472     <filename class="headerfile">atomic</filename>,
 473     <filename class="headerfile">chrono</filename>,
 474     <filename class="headerfile">condition_variable</filename>,
 475     <filename class="headerfile">forward_list</filename>,
 476     <filename class="headerfile">initializer_list</filename>,
 477     <filename class="headerfile">mutex</filename>,
 478     <filename class="headerfile">ratio</filename>,
 479     <filename class="headerfile">thread</filename>
 480   </para>
 481 </listitem>
 482
 483 <listitem>
 484   <para>
 485     Updated and improved.
 486   </para>
 487   <para>
 488     <filename class="headerfile">algorithm</filename>,
 489     <filename class="headerfile">system_error</filename>,
 490     <filename class="headerfile">type_traits</filename>
 491   </para>
 492 </listitem>
 493
 494 <listitem>
 495   <para>
 496     Use of the GNU extension namespace association converted to inline namespaces.
 497   </para>
 498 </listitem>
 499
 500 <listitem>
 501   <para>
 502     Preliminary support for <classname>initializer_list</classname>
 503     and defaulted and deleted constructors in container classes.
 504   </para>
 505 </listitem>
 506
 507 <listitem>
 508   <para>
 509     <classname>unique_ptr</classname>.
 510   </para>
 511 </listitem>
 512
 513 <listitem>
 514   <para>
 515     Support for new character types <type>char16_t</type>
 516     and <type>char32_t</type> added
 517     to <classname>char_traits</classname>, <classname>basic_string</classname>, <classname>numeric_limits</classname>,
 518     and assorted compile-time type traits.
 519   </para>
 520 </listitem>
 521
 522 <listitem>
 523   <para>
 524     Support for string conversions <function>to_string</function>
 525     and <function>to_wstring</function>.
 526   </para>
 527 </listitem>
 528
 529 <listitem>
 530   <para>
 531     Member functions taking string arguments were added to iostreams
 532     including <classname>basic_filebuf</classname>, <classname>basic_ofstream</classname>,
 533     and <classname>basic_ifstream</classname>.
 534   </para>
 535 </listitem>
 536
 537 <listitem>
 538   <para>
 539     Exception propagation support,
 540     including <classname>exception_ptr</classname>, <function>current_exception</function>, <function>copy_exception</function>,
 541     and <function>rethrow_exception</function>.
 542   </para>
 543 </listitem>
 544 </itemizedlist>
 545
 546
 547   <para>
 548 Uglification of <literal>try</literal> to <literal>__try</literal>
 549 and <literal>catch</literal> to <literal>__catch</literal>.
 550   </para>
 551
 552   <para>
 553 Audit of internal mutex usage, conversion to functions returning static
 554 local mutex.
 555   </para>
 556
 557 <para> Extensions
 558 added: <filename class="headerfile">ext/pointer.h</filename>
 559 and <filename class="headerfile">ext/extptr_allocator.h</filename>. Support
 560 for non-standard pointer types has been added
 561 to <classname>vector</classname>
 562 and <classname>forward_list</classname>.
 563 </para>
 564 </section>
 565
 566 <section xml:id="api.rel_450"><info><title><constant>4.5</constant></title></info>
 567
 568   <para>
 569   </para>
 570
 571 <para>
 572 C++0X features.
 573 </para>
 574
 575 <itemizedlist>
 576 <listitem>
 577   <para>
 578     Added.
 579   </para>
 580   <para>
 581     <filename class="headerfile">functional</filename>,
 582     <filename class="headerfile">future</filename>,
 583     <filename class="headerfile">random</filename>
 584   </para>
 585 </listitem>
 586
 587 <listitem>
 588   <para>
 589     Updated and improved.
 590   </para>
 591   <para>
 592     <filename class="headerfile">atomic</filename>,
 593     <filename class="headerfile">system_error</filename>,
 594     <filename class="headerfile">type_traits</filename>
 595   </para>
 596 </listitem>
 597
 598 <listitem>
 599   <para>
 600     Add support for explicit operators and standard layout types.
 601   </para>
 602 </listitem>
 603 </itemizedlist>
 604
 605 <para>
 606 Profile mode first appears.
 607 </para>
 608
 609 <para>
 610 Support for decimal floating-point arithmetic, including <classname>decimal32</classname>, <classname>decimal64</classname>, and <classname>decimal128</classname>.
 611 </para>
 612
 613 <para>
 614 Python pretty-printers are added for use with appropriately-advanced versions of <command>gdb</command>.
 615 </para>
 616
 617 <para>
 618 Audit for application of function attributes notrow, const, pure, and noreturn.
 619 </para>
 620
 621 <para>
 622 The default behavior for comparing typeinfo names changed, so
 623 in <filename class="headerfile">typeinfo</filename>, <literal>__GXX_MERGED_TYPEINFO_NAMES</literal>
 624 now defaults to zero.
 625 </para>
 626
 627 <para> Extensions modified: <filename class="headerfile">ext/throw_allocator.h</filename>.
 628 </para>
 629 </section>
 630
 631 </section>