libstdc++-v3/doc/xml/manual/status_cxx2017.xml

   1 <section xmlns="http://docbook.org/ns/docbook" version="5.0"
   2          xml:id="status.iso.2017" xreflabel="Status C++ 2017">
   3 <?dbhtml filename="status_iso_cxx2017.html"?>
   4
   5 <info><title>C++ 2017</title>
   6   <keywordset>
   7     <keyword>ISO C++</keyword>
   8     <keyword>2017</keyword>
   9   </keywordset>
  10 </info>
  11
  12 <para>
  13 In this implementation the <literal>-std=gnu++17</literal> or
  14 <literal>-std=c++17</literal> flag must be used to enable language
  15 and library
  16 features. See <link linkend="manual.intro.using.flags">dialect</link>
  17 options. The pre-defined symbol
  18 <constant>__cplusplus</constant> is used to check for the
  19 presence of the required flag.
  20 </para>
  21
  22 <para>
  23 This section describes the C++17 and library TS support in mainline GCC SVN,
  24 not in any particular release.
  25 </para>
  26
  27 <para>
  28 The following table lists new library features that have been accepted into
  29 the C++17 working draft. The "Proposal" column provides a link to the
  30 ISO C++ committee proposal that describes the feature, while the "Status"
  31 column indicates the first version of GCC that contains an implementation of
  32 this feature (if it has been implemented).
  33 The "SD-6 Feature Test" column shows the corresponding macro or header from
  34 <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="https://isocpp.org/std/standing-documents/sd-6-sg10-feature-test-recommendations">SD-6:
  35 Feature-testing recommendations for C++</link>.
  36 </para>
  37
  38 <table frame="all" xml:id="table.cxx17_status">
  39 <title>C++ 2017 Implementation Status</title>
  40
  41 <tgroup cols="4" align="left" colsep="0" rowsep="1">
  42 <colspec colname="c1"/>
  43 <colspec colname="c2"/>
  44 <colspec colname="c3"/>
  45 <colspec colname="c4"/>
  46   <thead>
  47     <row>
  48       <entry>Library Feature</entry>
  49       <entry>Proposal</entry>
  50       <entry>Status</entry>
  51       <entry>SD-6 Feature Test</entry>
  52     </row>
  53   </thead>
  54
  55   <tbody>
  56
  57     <row>
  58       <?dbhtml bgcolor="#C8B0B0" ?>
  59       <entry>
  60         <code>constexpr std::hardware_{constructive,destructive}_interference_size</code>
  61       </entry>
  62       <entry>
  63         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0154r1.html">
  64         P0154R1
  65         </link>
  66       </entry>
  67       <entry align="center"> No </entry>
  68       <entry> <code>__cpp_lib_hardware_interference_size >= 201603</code> </entry>
  69     </row>
  70
  71     <row>
  72       <entry> Core Issue 1776: Replacement of class objects containing reference members</entry>
  73       <entry>
  74         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0137r1.html">
  75         P0137R1
  76         </link>
  77       </entry>
  78       <entry align="center"> 7.1 </entry>
  79       <entry> <code>__cpp_lib_launder >= 201606</code> </entry>
  80     </row>
  81
  82     <row>
  83       <entry>Wording for <code>std::uncaught_exceptions</code></entry>
  84       <entry>
  85         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/JTC1/sc22/WG21/docs/papers/2014/n4259.pdf">
  86           N4259
  87         </link>
  88       </entry>
  89       <entry align="center">6.1</entry>
  90       <entry><code>__cpp_lib_uncaught_exceptions >= 201411</code></entry>
  91     </row>
  92
  93     <row>
  94       <entry> Variant: a type-safe union for C++17 </entry>
  95       <entry>
  96         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0088r3.html">
  97         P0088R3
  98         </link>
  99       </entry>
 100       <entry align="center"> 7.1 </entry>
 101       <entry> <code>__has_include(&lt;variant&gt;)</code>,
 102               <code>__cpp_lib_variant >= 201603</code>
 103               (since 7.3, see Note 1)
 104       </entry>
 105     </row>
 106
 107     <row>
 108       <entry> Library Fundamentals V1 TS Components: <code>optional</code> </entry>
 109       <entry>
 110         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0220r1.html">
 111         P0220R1
 112         </link>
 113       </entry>
 114       <entry align="center"> 7.1 </entry>
 115       <entry> <code>__has_include(&lt;optional&gt;)</code>,
 116               <code>__cpp_lib_optional >= 201603</code>
 117               (since 7.3, see Note 1)
 118       </entry>
 119     </row>
 120
 121     <row>
 122       <entry> Library Fundamentals V1 TS Components: <code>any</code> </entry>
 123       <entry>
 124         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0220r1.html">
 125         P0220R1
 126         </link>
 127       </entry>
 128       <entry align="center"> 7.1 </entry>
 129       <entry> <code>__has_include(&lt;any&gt;)</code>,
 130               <code>__cpp_lib_any >= 201603</code>
 131               (since 7.3, see Note 1)
 132       </entry>
 133     </row>
 134
 135     <row>
 136       <entry> Library Fundamentals V1 TS Components: <code>string_view</code> </entry>
 137       <entry>
 138         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0220r1.html">
 139         P0220R1
 140         </link>
 141       </entry>
 142       <entry align="center"> 7.1 </entry>
 143       <entry> <code>__has_include(&lt;string_view&gt;)</code>,
 144               <code>__cpp_lib_string_view >= 201603</code>
 145               (since 7.3, see Note 1)
 146       </entry>
 147     </row>
 148
 149     <row>
 150       <entry> Library Fundamentals V1 TS Components: <code>memory_resource</code> </entry>
 151       <entry>
 152         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0220r1.html">
 153         P0220R1
 154         </link>
 155       </entry>
 156       <entry align="center"> 9.1 </entry>
 157       <entry> <code>__has_include(&lt;memory_resource&gt;)</code>,
 158               <code>__cpp_lib_memory_resource >= 201603</code>
 159       </entry>
 160     </row>
 161
 162     <row>
 163       <entry> Library Fundamentals V1 TS Components: <code>apply</code> </entry>
 164       <entry>
 165         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0220r1.html">
 166         P0220R1
 167         </link>
 168       </entry>
 169       <entry align="center"> 7.1 </entry>
 170       <entry> <code>__cpp_lib_apply >= 201603</code> </entry>
 171     </row>
 172
 173     <row>
 174       <entry> Library Fundamentals V1 TS Components: <code>shared_ptr&lt;T[]&gt;</code> </entry>
 175       <entry>
 176         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0220r1.html">
 177         P0220R1
 178         </link>
 179       </entry>
 180       <entry align="center"> 7.1 </entry>
 181       <entry> <code>__cpp_lib_shared_ptr_arrays >= 201603</code> </entry>
 182     </row>
 183
 184     <row>
 185       <entry> Library Fundamentals V1 TS Components: Searchers </entry>
 186       <entry>
 187         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0220r1.html">
 188         P0220R1
 189         </link>
 190       </entry>
 191       <entry align="center"> 7.1 </entry>
 192       <entry> <code>__cpp_lib_boyer_moore_searcher >= 201603</code> </entry>
 193     </row>
 194
 195     <row>
 196       <entry> Library Fundamentals V1 TS Components: Sampling </entry>
 197       <entry>
 198         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0220r1.html">
 199         P0220R1
 200         </link>
 201       </entry>
 202       <entry align="center"> 7.1 </entry>
 203       <entry> <code>__cpp_lib_sample >= 201603</code> </entry>
 204     </row>
 205
 206     <row>
 207       <entry> Constant View: A proposal for a <code>std::as_const</code> helper function template       </entry>
 208       <entry>
 209         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="">
 210         P0007R1
 211         </link>
 212       </entry>
 213       <entry align="center"> 7.1 </entry>
 214       <entry><code> __cpp_lib_as_const >= 201510 </code></entry>
 215     </row>
 216
 217     <row>
 218       <entry> Improving pair and tuple </entry>
 219       <entry>
 220         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/n4387">
 221         N4387
 222         </link>
 223       </entry>
 224       <entry align="center"> 6.1 </entry>
 225       <entry> N/A </entry>
 226     </row>
 227
 228     <row>
 229       <entry> <code>make_from_tuple</code>: apply for construction </entry>
 230       <entry>
 231         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0209r2.pdf">
 232         P0209R2
 233         </link>
 234       </entry>
 235       <entry align="center"> 7.1 </entry>
 236       <entry><code> __cpp_lib_make_from_tuple >= 201606 </code></entry>
 237     </row>
 238
 239     <row>
 240       <?dbhtml bgcolor="#C8B0B0" ?>
 241       <entry>
 242         Removing <code>auto_ptr</code>, <code>random_shuffle()</code>,
 243         And Old <code>&lt;functional&gt;</code> Stuff
 244       </entry>
 245       <entry>
 246         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2014/n4190.htm">
 247           N4190
 248         </link>
 249       </entry>
 250       <entry align="center">No (kept for backwards compatibility)</entry>
 251       <entry/>
 252     </row>
 253
 254     <row>
 255       <?dbhtml bgcolor="#C8B0B0" ?>
 256       <entry> Deprecating Vestigial Library Parts in C++17 </entry>
 257       <entry>
 258         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0174r2.html">
 259         P0174R2
 260         </link>
 261       </entry>
 262       <entry align="center"> No  (kept for backwards compatibility)</entry>
 263       <entry/>
 264     </row>
 265
 266     <row>
 267       <entry> Making <code>std::owner_less</code> more flexible </entry>
 268       <entry>
 269         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/p0074r0.html">
 270         P0074R0
 271         </link>
 272       </entry>
 273       <entry align="center"> 7.1 </entry>
 274       <entry><code> __cpp_lib_transparent_operators >= 201510 </code></entry>
 275     </row>
 276
 277     <row>
 278       <entry> <code>std::addressof</code> should be constexpr </entry>
 279       <entry>
 280         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0304r0.html#2296">
 281         LWG2296
 282         </link>
 283       </entry>
 284       <entry align="center"> 7.1 </entry>
 285       <entry><code> __cpp_lib_addressof_constexpr >= 201603 </code></entry>
 286     </row>
 287
 288     <row>
 289       <entry> Safe conversions in <code>unique_ptr&lt;T[]&gt;</code> </entry>
 290       <entry>
 291         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2014/n4089.pdf">
 292         N4089
 293         </link>
 294       </entry>
 295       <entry align="center"> 6 </entry>
 296       <entry/>
 297     </row>
 298
 299     <row>
 300       <entry> LWG 2228: Missing SFINAE rule in unique_ptr templated assignment </entry>
 301       <entry>
 302         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/n4366.html">
 303           N4366
 304         </link>
 305       </entry>
 306       <entry align="center"> 6 </entry>
 307       <entry/>
 308     </row>
 309
 310     <row>
 311       <entry> Re-enabling <code>shared_from_this</code></entry>
 312       <entry>
 313         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0033r1.html">
 314         P0033R1
 315         </link>
 316       </entry>
 317       <entry align="center"> 7.1 </entry>
 318       <entry><code>__cpp_lib_enable_shared_from_this >= 201603</code></entry>
 319     </row>
 320
 321     <row>
 322       <entry> A proposal to add <code>invoke</code> function template </entry>
 323       <entry>
 324         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2014/n4169.html">
 325         N4169
 326         </link>
 327       </entry>
 328       <entry align="center"> 6.1 </entry>
 329       <entry><code> __cpp_lib_invoke >= 201411 </code></entry>
 330     </row>
 331
 332     <row>
 333       <entry>TriviallyCopyable <code>reference_wrapper</code> </entry>
 334       <entry>
 335         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2014/n4277.html">
 336           N4277
 337         </link>
 338       </entry>
 339       <entry align="center"> 5.1 </entry>
 340       <entry/>
 341     </row>
 342
 343     <row>
 344       <entry> Adopt <code>not_fn</code> from Library Fundamentals 2 for C++17 </entry>
 345       <entry>
 346         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0005r4.html">
 347         P0005R4
 348         </link>
 349       </entry>
 350       <entry align="center"> 7.1 </entry>
 351       <entry><code>__cpp_lib_not_fn >= 201603</code></entry>
 352     </row>
 353
 354     <row>
 355       <entry> Fixes for <code>not_fn</code> </entry>
 356       <entry>
 357         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0358r1.html">
 358         P0358R1
 359         </link>
 360       </entry>
 361       <entry align="center"> 7.1 </entry>
 362       <entry/>
 363     </row>
 364
 365     <row>
 366       <entry> Fixing a design mistake in the searchers interface in Library Fundamentals </entry>
 367       <entry>
 368         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0253r1.pdf">
 369         P0253R1
 370         </link>
 371       </entry>
 372       <entry align="center"> 7.1 </entry>
 373       <entry/>
 374     </row>
 375
 376     <row>
 377       <entry> Extending memory management tools </entry>
 378       <entry>
 379         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0040r3.html">
 380         P0040R3
 381         </link>
 382       </entry>
 383       <entry align="center"> 7.1 </entry>
 384       <entry><code> </code></entry>
 385     </row>
 386
 387     <row>
 388       <entry> <code>shared_ptr::weak_type</code></entry>
 389       <entry>
 390         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/p0163r0.html">
 391         P0163R0
 392         </link>
 393       </entry>
 394       <entry align="center"> 7.1 </entry>
 395       <entry><code> __cpp_lib_shared_ptr_weak_type >= 201606</code></entry>
 396     </row>
 397
 398     <row>
 399       <entry>Transformation Trait Alias <code>void_t</code></entry>
 400       <entry>
 401         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/JTC1/sc22/WG21/docs/papers/2014/n3911.pdf">
 402           N3911
 403         </link>
 404       </entry>
 405       <entry align="center">6.1</entry>
 406       <entry><code> __cpp_lib_void_t >= 201411</code></entry>
 407     </row>
 408
 409     <row>
 410       <entry> Wording for <code>bool_constant</code>, revision 1 </entry>
 411       <entry>
 412         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/n4389.html">
 413           N4389
 414         </link>
 415       </entry>
 416       <entry align="center">6.1</entry>
 417       <entry><code> __cpp_lib_bool_constant >= 201505</code></entry>
 418     </row>
 419
 420     <row>
 421       <entry> Adopt Type Traits Variable Templates from Library Fundamentals TS for C++17</entry>
 422       <entry>
 423         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/p0006r0.html">
 424         P0006R0
 425         </link>
 426       </entry>
 427       <entry align="center"> 7.1 </entry>
 428       <entry><code> __cpp_lib_type_trait_variable_templates >= 201510 </code></entry>
 429     </row>
 430
 431     <row>
 432       <entry> Logical Operator Type Traits</entry>
 433       <entry>
 434         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/p0013r1.html">
 435         P0013R1
 436         </link>
 437       </entry>
 438       <entry align="center"> 6.1 </entry>
 439       <entry><code> __cpp_lib_logical_traits >= 201510 </code></entry>
 440     </row>
 441
 442     <row>
 443       <entry> Adding [nothrow-]swappable traits </entry>
 444       <entry>
 445         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0185r1.html">
 446         P0185R1
 447         </link>
 448       </entry>
 449       <entry align="center"> 7 (<code>__is_swappable</code> available since 6.1)</entry>
 450       <entry><code> __cpp_lib_is_swappable >= 201603 </code></entry>
 451     </row>
 452
 453     <row>
 454       <entry> <code>is_callable</code>, the missing INVOKE related trait</entry>
 455       <entry>
 456         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0077r2.html">
 457         P0077R2
 458         </link>
 459       </entry>
 460       <entry align="center"> 7.1 </entry>
 461       <entry><code> __cpp_lib_is_callable >= 201603 </code></entry>
 462     </row>
 463
 464     <row>
 465       <entry> has_unique_object_representations </entry>
 466       <entry>
 467         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0258r2.html">
 468         P0258R2
 469         </link>
 470       </entry>
 471       <entry align="center"> 7.1 </entry>
 472       <entry><code> __cpp_lib_has_unique_object_representations >= 201606 </code></entry>
 473     </row>
 474
 475     <row>
 476       <entry> Polishing <code>&lt;chrono&gt;</code> </entry>
 477       <entry>
 478         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/p0092r1.html">
 479         P0092R1
 480         </link>
 481       </entry>
 482       <entry align="center"> 7.1 </entry>
 483       <entry><code> __cpp_lib_chrono >= 201510 </code></entry>
 484     </row>
 485
 486     <row>
 487       <entry> Adding more constexpr to <code>&lt;chrono&gt;</code> </entry>
 488       <entry>
 489         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0505r0.html">
 490         P0505R0
 491         </link>
 492       </entry>
 493       <entry align="center"> 7.1 </entry>
 494       <entry><code> __cpp_lib_chrono >= 201611 </code>
 495              (since 7.3, see Note 2)
 496       </entry>
 497     </row>
 498
 499     <row>
 500       <entry> Constexpr for <code>std::char_traits</code> </entry>
 501       <entry>
 502         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0426r1.html">
 503         P0426R1
 504         </link>
 505       </entry>
 506       <entry align="center"> 8.1 </entry>
 507       <entry><code> __cpp_lib_constexpr_char_traits >= 201611 </code></entry>
 508     </row>
 509
 510     <row>
 511       <entry> Integrating <code>std::string_view</code> and <code>std::string</code> </entry>
 512       <entry>
 513         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0254r2.pdf">
 514         P0254R2
 515         </link>
 516       </entry>
 517       <entry align="center"> 7.1 </entry>
 518       <entry><code> </code></entry>
 519     </row>
 520
 521     <row>
 522       <entry> Give 'std::string' a non-const '.data()' member function </entry>
 523       <entry>
 524         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0272r1.html">
 525         P0272R1
 526         </link>
 527       </entry>
 528       <entry align="center"> 7.1 </entry>
 529       <entry><code> </code></entry>
 530     </row>
 531
 532     <row>
 533       <entry>Cleaning-up noexcept in the Library</entry>
 534       <entry>
 535         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2014/n4258.pdf">
 536           N4258
 537         </link>
 538       </entry>
 539       <entry align="center">6.1</entry>
 540       <entry><code> __cpp_lib_allocator_traits_is_always_equal >= 201411 </code></entry>
 541     </row>
 542
 543     <row>
 544       <entry>Contiguous Iterators </entry>
 545       <entry>
 546         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2014/n4284.html">
 547           N4284
 548         </link>
 549       </entry>
 550       <entry align="center">N/A</entry>
 551       <entry/>
 552     </row>
 553
 554     <row>
 555       <entry> Minimal incomplete type support for standard containers </entry>
 556       <entry>
 557         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/n4510.html">
 558         N4510
 559         </link>
 560       </entry>
 561       <entry align="center"> 3.0 </entry>
 562       <entry><code> __cpp_lib_incomplete_container_elements >= 201505 </code>
 563              (since 6.2, see Note 2)
 564       </entry>
 565     </row>
 566
 567     <row>
 568       <entry> Emplace return type </entry>
 569       <entry>
 570         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0084r2.pdf">
 571         P0084R2
 572         </link>
 573       </entry>
 574       <entry align="center"> 7.1 </entry>
 575       <entry/>
 576     </row>
 577
 578     <row>
 579       <entry>Improved insertion interface for unique-key maps</entry>
 580       <entry>
 581         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2014/n4279.html">
 582           N4279
 583         </link>
 584       </entry>
 585       <entry align="center"> 6.1 </entry>
 586       <entry><code> __cpp_lib_map_try_emplace >= 201411</code>,
 587              <code> __cpp_lib_unordered_map_try_emplace >= 201411</code>
 588       </entry>
 589     </row>
 590
 591     <row>
 592       <entry> Splicing Maps and Sets </entry>
 593       <entry>
 594         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0083r3.pdf">
 595         P0083R3
 596         </link>
 597       </entry>
 598       <entry align="center"> 7.1 </entry>
 599       <entry><code> __cpp_lib_node_extract >= 201606 </code></entry>
 600     </row>
 601
 602     <row>
 603       <entry>Non-member <code>size()</code> and more</entry>
 604       <entry>
 605         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2014/n4280.pdf">
 606           N4280
 607         </link>
 608       </entry>
 609       <entry align="center"> 6.1 </entry>
 610       <entry><code> __cpp_lib_nonmember_container_access >= 201411 </code></entry>
 611     </row>
 612
 613     <row>
 614       <entry> A Proposal to Add Constexpr Modifiers to <code>reverse_iterator</code>, <code>move_iterator</code>, <code>array</code> and Range Access </entry>
 615       <entry>
 616         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/p0031r0.html">
 617         P0031R0
 618         </link>
 619       </entry>
 620       <entry align="center"> 7.1 </entry>
 621       <entry><code> __cpp_lib_array_constexpr >= 201603 </code></entry>
 622     </row>
 623
 624     <row>
 625       <?dbhtml bgcolor="#C8B0B0" ?>
 626       <entry> The Parallelism TS Should be Standardized  </entry>
 627       <entry>
 628         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0024r2.html">
 629         P0024R2
 630         </link>
 631       </entry>
 632       <entry align="center"> No </entry>
 633       <entry><code> __has_include(&lt;execution&gt;) </code>,
 634              <code> __cpp_lib_execution >= 201603 </code>,
 635              <code> __cpp_lib_parallel_algorithm >= 201603 </code>
 636       </entry>
 637     </row>
 638
 639     <row>
 640       <entry> An algorithm to "clamp" a value between a pair of boundary values </entry>
 641       <entry>
 642         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/p0025r0.html">
 643         P0025R0
 644         </link>
 645       </entry>
 646       <entry align="center"> 7.1 </entry>
 647       <entry><code> __cpp_lib_clamp >= 201603 </code></entry>
 648     </row>
 649
 650     <row>
 651       <entry> Adopt Selected Library Fundamentals V2 Components for C++17 </entry>
 652       <entry>
 653         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0295r0.pdf">
 654         P0295R0
 655         </link>
 656       </entry>
 657       <entry align="center"> 7.1 </entry>
 658       <entry><code> __cpp_lib_gcd_lcm >= 201606 </code></entry>
 659     </row>
 660
 661     <row>
 662       <entry> Proposal to Introduce a 3-Argument Overload to <code>std::hypot</code> </entry>
 663       <entry>
 664         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/p0030r1.pdf">
 665         P0030R1
 666         </link>
 667       </entry>
 668       <entry align="center"> 7.1 </entry>
 669       <entry><code> __cpp_lib_hypot >= 201603 </code></entry>
 670     </row>
 671
 672     <row>
 673       <entry> Mathematical Special Functions for C++17 </entry>
 674       <entry>
 675         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0226r1.pdf">
 676         P0226R1
 677         </link>
 678       </entry>
 679       <entry align="center"> 7.1 </entry>
 680       <entry><code> __cpp_lib_math_special_functions >= 201603 </code>
 681              (see Note 3)
 682       </entry>
 683     </row>
 684
 685     <row>
 686       <entry>Adopt the File System TS for C++17  </entry>
 687       <entry>
 688         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0218r1.html">
 689         P0218R1
 690         </link>
 691       </entry>
 692       <entry align="center"> 8.1 </entry>
 693       <entry><code> __has_include(&lt;filesystem&gt;) </code>,
 694              <code> __cpp_lib_filesystem >= 201603 </code>
 695              (GCC 8.x requires linking with <code>-lstdc++fs</code>)
 696       </entry>
 697     </row>
 698
 699     <row>
 700       <entry> Relative Paths for Filesystem</entry>
 701       <entry>
 702         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0219r1.html">
 703         P0219R1
 704         </link>
 705       </entry>
 706       <entry align="center"> 8.1 </entry>
 707       <entry><code> __cpp_lib_filesystem >= 201606 </code></entry>
 708     </row>
 709
 710     <row>
 711       <entry> Adapting string_view by filesystem paths </entry>
 712       <entry>
 713         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0392r0.pdf">
 714         P0392R0
 715         </link>
 716       </entry>
 717       <entry align="center"> 8.1 </entry>
 718       <entry><code> __cpp_lib_filesystem >= 201606 </code></entry>
 719     </row>
 720
 721     <row>
 722       <entry> Directory Entry Caching for Filesystem </entry>
 723       <entry>
 724        <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0317r1.html">
 725        P0317R1
 726        </link>
 727       </entry>
 728       <entry align="center"> 8.1 </entry>
 729       <entry><code> __cpp_lib_filesystem >= 201703 </code></entry>
 730      </row>
 731
 732     <row>
 733       <entry> constexpr <code>atomic&lt;T&gt;::is_always_lock_free</code>        </entry>
 734       <entry>
 735         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0152r1.html">
 736         P0152R1
 737         </link>
 738       </entry>
 739       <entry align="center"> 7.1 </entry>
 740       <entry><code> __cpp_lib_atomic_is_always_lock_free >= 201603 </code></entry>
 741     </row>
 742
 743     <row>
 744       <entry>A proposal to add <code>shared_mutex</code> (untimed) (Revision 4)</entry>
 745       <entry>
 746         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/n4508.html">
 747           N4508
 748         </link>
 749       </entry>
 750       <entry align="center"> 6.1 </entry>
 751       <entry><code> __cpp_lib_shared_mutex >= 201505 </code></entry>
 752     </row>
 753
 754     <row>
 755       <entry> Variadic <code>lock_guard</code> (Rev. 5) </entry>
 756       <entry>
 757         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2017/p0156r2.html">
 758         P0156R2
 759         </link>
 760       </entry>
 761       <entry align="center"> 7.1 </entry>
 762       <entry><code> __cpp_lib_scoped_lock >= 201703 </code></entry>
 763     </row>
 764
 765     <row>
 766       <entry> A byte type definition </entry>
 767       <entry>
 768         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2017/p0298r3.pdf">
 769         P0298R3
 770         </link>
 771       </entry>
 772       <entry align="center"> 7.1 </entry>
 773       <entry><code> __cpp_lib_byte >= 201603 </code> (since 7.3, see Note 2)
 774       </entry>
 775     </row>
 776
 777     <row>
 778       <?dbhtml bgcolor="#B0B0B0" ?>
 779       <entry> Elementary string conversions </entry>
 780       <entry>
 781         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0067r5.html">
 782         P0067R5
 783         </link>
 784       </entry>
 785       <entry align="center"> 8.1 (only integral types supported) </entry>
 786       <entry><code> __has_include(&lt;charconv&gt;) </code>
 787              <code> __cpp_lib_to_chars >= 201611 </code></entry>
 788     </row>
 789
 790     <row>
 791       <entry> Homogeneous interface for variant, any and optional </entry>
 792       <entry>
 793         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0032r3.pdf">
 794         P0032R3
 795         </link>
 796       </entry>
 797       <entry align="center"> 7.1  </entry>
 798       <entry>
 799              <code> __cpp_lib_any >= 201606 </code>,
 800              <code> __cpp_lib_optional >= 201606 </code>,
 801              <code> __cpp_lib_variant >= 201606 </code>
 802       </entry>
 803     </row>
 804
 805     <row>
 806       <entry> Making Optional Greater Equal Again </entry>
 807       <entry>
 808         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0307r2.pdf">
 809         P0307R2
 810         </link>
 811       </entry>
 812       <entry align="center"> 7.1  </entry>
 813       <entry> <code> __cpp_lib_optional >= 201606 </code> </entry>
 814     </row>
 815
 816   </tbody>
 817 </tgroup>
 818 </table>
 819
 820 <para>
 821 Note 1: This feature is supported in GCC 7.1 and 7.2 but before GCC 7.3 the
 822 <code>__cpp_lib</code> macro is not defined, and compilation will fail if the
 823 header is included without using <option>-std</option> to enable C++17 support.
 824 </para>
 825
 826 <para>
 827 Note 2: This feature is supported in older releases but the
 828 <code>__cpp_lib</code> macro is not defined to the right value
 829 (or not defined at all) until the version shown in parentheses.
 830 </para>
 831
 832 <para>
 833 Note 3: The mathematical special functions are enabled in C++17 mode from
 834 GCC 7.1 onwards. For GCC 6.x or for C++11/C++14 define
 835 <code>__STDCPP_WANT_MATH_SPEC_FUNCS__</code> to a non-zero value
 836 and test for <code>__STDCPP_MATH_SPEC_FUNCS__ >= 201003L</code>.
 837 </para>
 838
 839 <table frame="all" xml:id="table.cxx17_ts_status">
 840 <title>C++ Technical Specifications Implementation Status</title>
 841
 842 <tgroup cols="4" align="left" colsep="0" rowsep="1">
 843 <colspec colname="c1"/>
 844 <colspec colname="c2"/>
 845 <colspec colname="c3"/>
 846 <colspec colname="c4"/>
 847   <thead>
 848     <row>
 849       <entry>Paper</entry>
 850       <entry>Title</entry>
 851       <entry>Status</entry>
 852       <entry>Comments</entry>
 853     </row>
 854   </thead>
 855
 856   <tbody>
 857
 858     <row>
 859       <entry>
 860         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/JTC1/SC22/WG21/docs/papers/2014/n4076.html">
 861           N4076
 862         </link>
 863       </entry>
 864       <entry>A generalized callable negator</entry>
 865       <entry>Y</entry>
 866       <entry>Library Fundamentals 2 TS</entry>
 867     </row>
 868
 869     <row>
 870       <entry>
 871         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/JTC1/SC22/WG21/docs/papers/2014/n4273.htm">
 872           N4273
 873         </link>
 874       </entry>
 875       <entry>Uniform Container Erasure</entry>
 876       <entry>Y</entry>
 877       <entry>Library Fundamentals 2 TS</entry>
 878     </row>
 879
 880     <row>
 881       <entry>
 882         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2014/n4061.pdf">
 883           N4061
 884         </link>
 885       </entry>
 886       <entry>Greatest Common Divisor and Least Common Multiple</entry>
 887       <entry>Y</entry>
 888       <entry>Library Fundamentals 2 TS</entry>
 889     </row>
 890
 891     <row>
 892       <entry>
 893         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2014/n4066.htm">
 894           N4066
 895         </link>
 896       </entry>
 897       <entry>Delimited iterators</entry>
 898       <entry>Y</entry>
 899       <entry>Library Fundamentals 2 TS</entry>
 900     </row>
 901
 902     <row>
 903       <entry>
 904         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2014/n4282.pdf">
 905           N4282
 906         </link>
 907       </entry>
 908       <entry>The World's Dumbest Smart Pointer</entry>
 909       <entry>Y</entry>
 910       <entry>Library Fundamentals 2 TS</entry>
 911     </row>
 912
 913
 914     <row>
 915       <entry>
 916         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/n4388.html">
 917           N4388
 918         </link>
 919       </entry>
 920       <entry>Const-Propagating Wrapper</entry>
 921       <entry>Y</entry>
 922       <entry>Library Fundamentals 2 TS</entry>
 923     </row>
 924
 925     <row>
 926       <entry>
 927         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/n4391.html">
 928           N4391
 929         </link>
 930       </entry>
 931       <entry> <code>make_array</code>, revision 4 </entry>
 932       <entry>Y</entry>
 933       <entry>Library Fundamentals 2 TS</entry>
 934     </row>
 935
 936     <row>
 937       <entry>
 938         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/n4502.pdf">
 939           N4502
 940         </link>
 941       </entry>
 942       <entry> Support for the C++ Detection Idiom, V2 </entry>
 943       <entry>Y</entry>
 944       <entry>Library Fundamentals 2 TS</entry>
 945     </row>
 946
 947     <row>
 948       <entry>
 949         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/n4519.pdf">
 950           N4519
 951         </link>
 952       </entry>
 953       <entry> Source-Code Information Capture </entry>
 954       <entry>Y</entry>
 955       <entry>Library Fundamentals 2 TS</entry>
 956     </row>
 957
 958     <row>
 959       <?dbhtml bgcolor="#C8B0B0" ?>
 960       <entry>
 961         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/n4521.html">
 962           N4521
 963         </link>
 964       </entry>
 965       <entry> Merge Fundamentals V1 into V2 </entry>
 966       <entry>
 967         N (components from V1 are still in namespace
 968         <code>fundamentals_v1</code>)
 969       </entry>
 970       <entry>Library Fundamentals 2 TS</entry>
 971     </row>
 972
 973     <row>
 974       <entry>
 975         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://open-std.org/JTC1/SC22/WG21/docs/papers/2015/p0013r1.html">
 976           P0013R1
 977         </link>
 978       </entry>
 979       <entry>Logical Operator Type Traits (revision 1)</entry>
 980       <entry>Y</entry>
 981       <entry>Library Fundamentals 2 TS</entry>
 982     </row>
 983
 984     <row>
 985       <entry>
 986         <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/n4531.html">
 987           N4531
 988         </link>
 989       </entry>
 990       <entry>std::rand replacement, revision 3</entry>
 991       <entry>Y</entry>
 992       <entry>Library Fundamentals 2 TS</entry>
 993     </row>
 994
 995   </tbody>
 996 </tgroup>
 997 </table>
 998
 999 <section xml:id="iso.2017.specific" xreflabel="Implementation Specific"><info><title>Implementation Specific Behavior</title></info>
1000
1001    <para>For behaviour which is also specified by previous standards,
1002       see <link linkend="iso.1998.specific">C++ 1998/2003 Implementation
1003       Specific Behavior</link> and <link linkend="iso.2011.specific">C++
1004       2011 Implementation Specific Behavior</link>. This section only
1005       documents behaviour which is new in the 2017 standard.
1006    </para>
1007
1008    <para>
1009       <emphasis>20.5.1.2 [headers]</emphasis>
1010       Whether names from Annex K are declared by C++ headers depends on
1011       whether the underlying C library supports Annex K and declares the
1012       names. For the GNU C library, there is no Annex K support and so
1013       none of its names are declared by C++ headers.
1014    </para>
1015
1016    <para>
1017       <emphasis>23.6.5 [optional.bad_optional_access]</emphasis>
1018       <code>what()</code> returns <literal>"bad optional access"</literal>.
1019    </para>
1020
1021    <para>
1022       <emphasis>23.7.3 [variant.variant]</emphasis>
1023       <classname>variant</classname> supports over-aligned types.
1024    </para>
1025
1026    <para>
1027       <emphasis>23.7.10 [variant.bad.access]</emphasis>
1028       <code>what()</code> returns <literal>"Unexpected index"</literal>.
1029    </para>
1030
1031    <para>
1032       <emphasis>23.12.5.2 [memory.resource.pool.options]</emphasis>
1033       Let S equal <code>numeric_limits&lt;size_t&gt;::digits</code>.
1034       The limit for maximum number of blocks in a chunk is given by
1035       <inlineequation><mathphrase>2<superscript>N</superscript>-1</mathphrase></inlineequation>,
1036       where N is <inlineequation><mathphrase>min(19, 3 + S/2)</mathphrase></inlineequation>.
1037       The largest allocation size that will be allocated from a pool is
1038       <inlineequation><mathphrase>2<superscript>22</superscript></mathphrase></inlineequation>
1039       when <inlineequation><mathphrase>S > 20</mathphrase></inlineequation>,
1040       otherwise 3072 when <inlineequation><mathphrase>S > 16</mathphrase></inlineequation>,
1041       otherwise 768.
1042    </para>
1043
1044    <para>
1045       <emphasis>23.12.6.1 [memory.resource.monotonic.buffer.ctor]</emphasis>
1046       The default <code>next_buffer_size</code> is <code>128 * sizeof(void*)</code>.
1047       The default growth factor is <code>1.5</code>.
1048    </para>
1049
1050    <para>
1051       <emphasis>23.15.4.3 [meta.unary.prop]</emphasis>
1052       The predicate condition for
1053       <code>has_unique_object_representations</code> is true for all scalar
1054       types except floating point types.
1055    </para>
1056
1057    <para>
1058       <emphasis>23.19.3 [execpol.type],
1059       28.4.3 [algorithms.parallel.exec]</emphasis>
1060       There are no implementation-defined execution policies.
1061    </para>
1062
1063    <para>
1064       <emphasis>24.4.2 [string.view.template]</emphasis>
1065       <classname>basic_string_view&lt;C, T&gt;::iterator</classname> is
1066       <code>C*</code> and
1067       <classname>basic_string_view&lt;C, T&gt;::const_iterator</classname> is
1068       <code>const C*</code>.
1069    </para>
1070
1071
1072    <para>
1073       <emphasis>28.4.3 [algorithms.parallel.exec]</emphasis>
1074       Threads of execution created by <classname>std::thread</classname>
1075       provide concurrent forward progress guarantees, so threads of execution
1076       implicitly created by the library will provide parallel forward
1077       progress guarantees.
1078    </para>
1079
1080    <para>
1081       <emphasis>29.4.1 [cfenv.syn]</emphasis>
1082       The effects of the <filename>&lt;cfenv&gt;</filename> functions
1083       depends on whether the <code>FENV_ACCESS</code> pragma is supported,
1084       and on the C library that provides the header.
1085    </para>
1086
1087    <para>
1088       <emphasis>29.6.9 [c.math.rand]</emphasis>
1089       Whether the <function>rand</function> function may introduce data
1090       races depends on the target C library that provides the function.
1091    </para>
1092
1093    <para>
1094       <emphasis>29.9.5 [sf.cmath]</emphasis>
1095       The effect of calling the mathematical special functions with large
1096       inputs should be documented here.
1097    </para>
1098
1099    <para>
1100       <emphasis>30.10.2.1 [fs.conform.9945]</emphasis>
1101       The behavior of the filesystem library implementation will depend on
1102       the target operating system. Some features will not be not supported
1103       on some targets.
1104    </para>
1105
1106    <para>
1107       <emphasis>30.10.5 [fs.filesystem.syn]</emphasis>
1108       The clock used for file times is an unspecified type
1109       with a signed 64-bit representation, capable of representing
1110       timestamps with nanosecond resolution. The clock's epoch is
1111       unspecified, but is not the same as the system clock's epoch.
1112    </para>
1113
1114    <para>
1115       <emphasis>30.10.7.1 [fs.path.generic]</emphasis>
1116       dot-dot in the root-directory refers to the root-directory itself.
1117       On Windows, a drive specifier such as <code>"C:"</code> or
1118       <code>"z:"</code> is treated as a root-name. On Cygwin, a path
1119       that begins with two successive directory separators is a
1120       root-name. Otherwise (for POSIX-like systems other than Cygwin),
1121       the implementation-defined root-name is an unspecified string
1122       which does not appear in any pathnames.
1123    </para>
1124
1125    <para>
1126       <emphasis>30.10.10.1 [fs.enum.path.format]</emphasis>
1127       The character sequence is always interpreted in the native pathname
1128       format.
1129    </para>
1130
1131    <para>
1132       <emphasis>30.10.15.4 [fs.op.file_size]</emphasis>
1133       If <code>!is_regular_file(p)</code>, an error is reported.
1134    </para>
1135
1136
1137 </section>
1138
1139 </section>