1<!DOCTYPE html> 2<!-- 3Copyright 2014 The Chromium Authors. All rights reserved. 4Use of this source code is governed by a BSD-style license that can be 5found in the LICENSE file. 6--> 7<html> 8<head> 9<meta charset="utf-8"> 10<link rel="stylesheet" href="c++11.css"> 11<style> 12table tbody tr td:first-child { 13 font-weight: bold; 14 font-size: 110%; 15} 16</style> 17</head> 18<body> 19<div id="content"> 20<h1>C++11 use in Chromium</h1> 21 22<p><i>This document lives at src/styleguide/c++/c++11.html in a Chromium 23checkout.</i></p> 24 25<p>This document summarizes the features of C++11 (both in the language itself 26and in enhancements to the Standard Library) and describes which features are 27allowed in Chromium and contains pointers to more detailed information. The 28Guide applies to Chromium and its subprojects. Subprojects can choose to be 29more restrictive if they need to compile on more toolchains than Chromium.</p> 30 31<p>You can propose to make a feature available or to ban a 32feature by sending an email to chromium-dev. Ideally include a short blurb 33on what the feature is, and why you think it should or should not be allowed. 34Ideally, the list will arrive at some consensus and the wiki page will be 35updated to mention that consensus. If there's no consensus, 36<code>src/styleguide/C++/OWNERS</code> get to decide -- for divisive features, we expect 37the decision to be to not use the feature yet and possibly discuss it again a 38few months later, when we have more experience with the language.</p> 39 40<p class="warning">Unless otherwise noted, <strong>no</strong> C++11 41<strong>library</strong> features are allowed.</p> 42 43<h2 id="whitelist">C++11 Allowed Features</h2> 44 45<p>The following features are currently allowed.</p> 46 47<table id="whitelist_lang_list" class="unlined striped"> 48<tbody> 49 50<tr> 51<th style='width:220px;'>Feature</th> 52<th style='width:260px;'>Snippet</th> 53<th style='width:240px;'>Description</th> 54<th style='width:240px;'>Documentation Link</th> 55<th style='width:240px;'>Notes and Discussion Thread</th> 56</tr> 57 58<tr> 59<td>Angle Bracket Parsing in Templates</td> 60<td><code>>></code> for <code>> ></code> and <br /> 61<code><::</code> for <code>< ::</code></td> 62<td>More intuitive parsing of template parameters</td> 63<td><a href="http://stackoverflow.com/questions/15785496/c-templates-angle-brackets-pitfall-what-is-the-c11-fix"> 64C++ Templates Angle Brackets Pitfall</a></td> 65<td>Recommended to increase readability. Approved without discussion.</td> 66</tr> 67 68<tr> 69<td>Automatic Types</td> 70<td><code>auto</code></td> 71<td>Automatic type deduction</td> 72<td>TODO: documentation link</td> 73<td>Use according to the <a 74href="https://google-styleguide.googlecode.com/svn/trunk/cppguide.html#auto">Google 75Style Guide on <code>auto</code></a>. <a href="https://groups.google.com/a/chromium.org/forum/#!topic/chromium-dev/OQyYSfH9m2M">Discussion thread</a></td> 76</tr> 77 78<tr> 79<td>Final Specifier</td> 80<td><code>final</code></td> 81<td> Indicates that a class or function is final and cannot be overridden</td> 82<td><a href="http://en.cppreference.com/w/cpp/language/final">final Language Reference</a></td> 83<td>Recommended for new code. Existing uses of the <code>FINAL</code> macro will be <a href="https://crbug.com/417463">replaced throughout the codebase</a>. <a href="https://groups.google.com/a/chromium.org/forum/#!topic/chromium-dev/VTNZzizN0zo">Discussion thread</a></td> 84</tr> 85 86<tr> 87<td>Local Types as Template Arguments</td> 88<td></td> 89<td>Allows local and unnamed types as template arguments</td> 90<td><a href="http://stackoverflow.com/questions/742607/using-local-classes-with-stl-algorithms"> 91Local types, types without linkage and unnamed types as template arguments</a></td> 92<td>Usage should be rare. Approved without discussion.</td> 93</tr> 94 95<tr> 96<td>Null Pointer Constant</td> 97<td><code>nullptr</code></td> 98<td>Declares a type-safe null pointer</td> 99<td>TODO: documentation link</td> 100<td>Recommended for new code. 101<a href="https://groups.google.com/a/chromium.org/forum/#!topic/chromium-dev/4mijeJHzxLg">Discussion thread</a>. 102<a href="https://google-styleguide.googlecode.com/svn/trunk/cppguide.html#0_and_nullptr/NULL">Google Style Guide</a>. 103Note: <code>std::nullptr_t</code> is a library feature and not available. 104</td> 105</tr> 106 107<tr> 108<td>Override Specifier</td> 109<td><code>override</code></td> 110<td>Indicates that a class or function overrides a base implementation</td> 111<td><a href="http://en.cppreference.com/w/cpp/language/override">override Language Reference</a></td> 112<td>Recommended for new code. Existing uses of the <code>OVERRIDE</code> macro will be <a href="https://crbug.com/417463">replaced throughout the codebase</a>. <a href="https://groups.google.com/a/chromium.org/forum/#!topic/chromium-dev/VTNZzizN0zo">Discussion</a></td> 113</tr> 114 115<tr> 116<td>Range-Based For Loops</td> 117<td><code>for (<i>type</i> <i>var</i> : <i>range</i>)</code></td> 118<td>Facilitates a more concise syntax for iterating over the elements 119of a container (or a range of iterators) in a <code>for</code> loop</td> 120<td>TODO: documentation link</td> 121<td>As a rule of thumb, use <code>for (const auto& ...)</code>, <code>for (auto& ...)</code>, or <code>for (<i>concrete type</i> ...)</code>. For pointers, use <code>for (auto* ...)</code> to make clear that the copy of the loop variable is intended, and only a pointer is copied. <a href="https://groups.google.com/a/chromium.org/forum/#!topic/chromium-dev/hpzz4EqbVmc">Discussion thread</a></td> 122</tr> 123 124<tr> 125<td>Standard Integers</td> 126<td>Typedefs within <code><stdint.h></code> 127and <code><inttypes></code></td> 128<td>Provides fixed-size integers independent of platforms</td> 129<td><a href="http://www.cplusplus.com/reference/cstdint/"> 130<stdint.h> (cstdint)</a></td> 131<td>Already in common use in the codebase. Approved without discussion.</td> 132</tr> 133 134<tr> 135<td>Static Assertions</td> 136<td><code>static_assert(<i>bool</i>, <i>string</i>)</code></td> 137<td>Tests compile-time conditions</td> 138<td><a href="http://en.cppreference.com/w/cpp/language/static_assert">Static Assertion</a></td> 139<td><a href="https://groups.google.com/a/chromium.org/forum/#!topic/chromium-dev/POISBQEhGzU">Discussion thread</a></td> 140</tr> 141 142<tr> 143<td>Variadic Macros</td> 144<td><code>#define <i>MACRO</i>(...) <i>Impl</i>(<i>args</i>, __VA_ARGS__)</code></td> 145<td>Allows macros that accept a variable number of arguments</td> 146<td><a href="http://stackoverflow.com/questions/4786649/are-variadic-macros-nonstandard"> 147Are Variadic macros nonstandard?</a></td> 148<td>Usage should be rare. <a href="https://groups.google.com/a/chromium.org/forum/#!topic/chromium-dev/sRx9j3CQqyA">Discussion thread</a></td> 149</tr> 150 151<tr> 152<td>Variadic Templates</td> 153<td><code>template <<i>typename</i> ... <i>arg</i>></code></td> 154<td>Allows templates that accept a variable number of arguments</td> 155<td>TODO: documentation link</td> 156<td>Usage should be rare. Use instead of .pump files. <a href="https://groups.google.com/a/chromium.org/forum/#!topic/chromium-dev/6ItymeMXpMc">Discussion thread</a></td> 157</tr> 158 159</tbody> 160</table> 161 162<h2 id="blacklist">C++11 Blacklist (Disallowed and Banned Features)</h2> 163 164<p>This section lists features that are not allowed to be used yet. 165 166<h3 id="blacklist_banned">C++11 Banned Features</h3> 167 168<p>This section will list C++11 features that are not allowed in the Chromium 169codebase. 170</p> 171 172<table id="banned_list" class="unlined striped"> 173<tbody> 174 175<tr> 176<th style='width:240px;'>Feature or Library</th> 177<th style='width:240px;'>Snippet</th> 178<th style='width:240px;'>Description</th> 179<th style='width:240px;'>Documentation Link</th> 180<th style='width:240px;'>Notes</th> 181</tr> 182 183<tr> 184<td>Constant Expressions</td> 185<td><code>constexpr</code></td> 186<td>Compile-time constant expressions</td> 187<td>TODO: documentation link</td> 188<td>Doesn't work in MSVS2013. Reevalute once it does.<a 189href="https://google-styleguide.googlecode.com/svn/trunk/cppguide.html#constexpr">Google 190Style Guide on <code>constexpr</code></a></td> 191</tr> 192 193<tr> 194<td>Function Local Variable</td> 195<td><code>__func__</code></td> 196<td>Provides a local variable of the name of the enclosing 197function for logging purposes</td> 198<td><a href="http://www.informit.com/guides/content.aspx?g=cplusplus&seqNum=338"> 199The __func__ Predeclared Identifier is Coming to C++</a></td> 200<td>Doesn't work in MSVS2013. Reevaluate once it does. <a href="https://groups.google.com/a/chromium.org/forum/#!topic/chromium-dev/ojGfcgSDzHM">Discussion thread</a></td> 201</tr> 202 203<tr> 204<td>Rvalue References (and Move Semantics)</td> 205<td><code>T(T&& t)</code> and <code>T& operator=(T&& t)</code></td> 206<td>Reference that only binds to a temporary object</td> 207<td>TODO: documentation link</td> 208<td>To be revisited in the future. Allowed in exceptional cases where approved by the OWNERS of src/styleguide/c++/.</td> 209</tr> 210 211<tr> 212<td>UTF-16 and UTF-32 Support (16-Bit and 32-Bit Character Types)</td> 213<td><code>char16_t</code> and <code>char32_t</code></td> 214<td>Provides character types for handling 16-bit 215and 32-bit code units (useful for encoding 216UTF-16 and UTF-32 string data)</td> 217<td><a href="http://en.cppreference.com/w/cpp/language/types"> 218Fundamental types</a></td> 219<td>Doesn't work in MSVS2013. Reevaluate once it does. Non-UTF-8 text is 220banned by the 221<a href="https://google-styleguide.googlecode.com/svn/trunk/cppguide.html#Non-ASCII_Characters"> 222C++ Style Guide</a>. However, may be useful for 223consuming non-ASCII data. <a href="https://groups.google.com/a/chromium.org/forum/#!topic/chromium-dev/ME2kL7_Kvyk">Discussion thread</a></td> 224</tr> 225 226<tr> 227<td>UTF-8, UTF-16, UTF-32 String Literals</td> 228<td><code>u8"<i>string</i>", u"<i>string</i>", U"<i>string</i>"</code></td> 229<td>Enforces UTF-8, UTF-16, UTF-32 encoding on all string literals</td> 230<td><a href="http://en.cppreference.com/w/cpp/language/string_literal"> 231string literal</a></td> 232<td>Does not yet work in MSVS2013. Reevaluate once it does. <a href="https://groups.google.com/a/chromium.org/forum/#!topic/chromium-dev/gcoUbcjfsII">Discussion thread</a></td> 233</tr> 234 235</tbody> 236</table> 237 238<h3 id="blacklist_review">C++11 Features To Be Discussed</h3> 239 240<p>The following C++ language features are currently disallowed. 241See the top of this page on how to propose moving a feature from this list 242into the allowed or banned sections. Note that not all of these features 243work in all our compilers yet.</p> 244 245<table id="blacklist_review_list" class="unlined striped"> 246<tbody> 247 248<tr> 249<th style='width:240px;'>Feature</th> 250<th style='width:240px;'>Snippet</th> 251<th style='width:240px;'>Description</th> 252<th style='width:240px;'>Documentation Link</th> 253<th style='width:240px;'>Notes</th> 254</tr> 255 256<tr> 257<td>Aliases</td> 258<td><code>using <i>new_alias</i> = <i>typename</i></code></td> 259<td>Allow parameterized typedefs</td> 260<td><a href="http://en.cppreference.com/w/cpp/language/type_alias">Type alias (using syntax)</a></td> 261<td><a href="https://groups.google.com/a/chromium.org/forum/#!topic/chromium-dev/8dOAMzgR4ao">Discussion thread</a></td> 262</tr> 263 264<tr> 265<td>Alignment Features</td> 266<td> 267<code>alignas</code> specifier, 268<code>std::alignment_of<T></code>, 269<code>std::aligned_union<Size, ...Types></code> and 270<code>std::max_align_t</code></td> 271<td>Object alignment</td> 272<td><a href="http://en.cppreference.com/w/cpp/types/alignment_of">std::alignment_of</a></td> 273<td></td> 274</tr> 275 276<tr> 277<td>Attributes</td> 278<td><code>[[<i>attribute_name</i>]]</code></td> 279<td>Attaches properties to declarations that 280specific compiler implementations may use.</td> 281<td><a href="http://www.codesynthesis.com/~boris/blog/2012/04/18/cxx11-generalized-attributes/"> 282C++11 generalized attributes</a></td> 283<td></td> 284</tr> 285 286<tr> 287<td>Declared Type Accessor</td> 288<td><code>decltype(<i>expression</i>)</code></td> 289<td>Provides a means to determine the type of an expression at compile-time, 290useful most often in templates.</td> 291<td><a href="http://en.cppreference.com/w/cpp/language/decltype"> 292decltype specifier</a></td> 293<td><a href="https://groups.google.com/a/chromium.org/forum/#!topic/chromium-dev/_zoNvZd_dSo">Discussion thread</a></td> 294</tr> 295 296<tr> 297<td>Default Function Creation</td> 298<td><code><i>Function</i>(<i>arguments</i>) = default;</code></td> 299<td>Instructs the compiler to generate a default version 300of the indicated function</td> 301<td><a href="http://stackoverflow.com/questions/823935/whats-the-point-in-defaulting-functions-in-c11"> 302What's the point in defaulting functions in C++11?</a></td> 303<td><a href="https://groups.google.com/a/chromium.org/forum/#!topic/chromium-dev/qgU4mh_MpGA">Discussion thread</a></td> 304</tr> 305 306<tr> 307<td>Default Function Template Arguments</td> 308<td><code>template <typename T = <i>type</i>> <br /> 309 <i>type</i> <i>Function</i>(T <i>var</i>) {}</code></td> 310<td>Allow function templates, like classes, to have default arguments</td> 311<td><a href="http://stackoverflow.com/questions/2447458/default-template-arguments-for-function-templates"> 312Default Template Arguments for Function Templates</a></td> 313<td></td> 314</tr> 315 316<tr> 317<td>Delegated Constructors</td> 318<td><code>Class() : Class(0) {}</code><br /> 319<code>Class(<i>type</i> <i>var</i>) : Class(<i>var</i>, 0)</code></td> 320<td>Allow overloaded constructors to use common initialization code</td> 321<td><a href="https://www.ibm.com/developerworks/community/blogs/5894415f-be62-4bc0-81c5-3956e82276f3/entry/introduction_to_the_c_11_feature_delegating_constructors?lang=en"> 322Introduction to the C++11 feature: delegating constructors</a></td> 323<td><a href="https://groups.google.com/a/chromium.org/forum/#!topic/chromium-dev/0zVA8Ctx3Xo">Discussion thread</a></td> 324</tr> 325 326<tr> 327<td>Enumerated Type Classes</td> 328<td><code>enum class <i>classname</i></code></td> 329<td>Provide enums as full classes, with no implicit 330conversion to booleans or integers</td> 331<td><a href="http://stackoverflow.com/questions/6936030/do-we-really-need-enum-class-in-c11"> 332enum-class</a></td> 333<td><a href="https://groups.google.com/a/chromium.org/forum/#!topic/chromium-dev/Q5WmkAImanc">Discussion thread</a></td> 334</tr> 335 336<tr> 337<td>Exception Features</td> 338<td><code>noexcept</code>, <code>exception_ptr</code>, 339<code>current_exception()</code>, <code>rethrow_exception</code>, 340and <code>nested_exception</code></td> 341<td>Enhancements to exception throwing and handling</td> 342<td><a href="http://en.cppreference.com/w/cpp/error/exception"> 343std::exception</a></td> 344<td>Exceptions are banned by the 345<a href="https://google-styleguide.googlecode.com/svn/trunk/cppguide.html#Exceptions"> C++ Style Guide</a>. <a href="https://groups.google.com/a/chromium.org/forum/#!topic/chromium-dev/8i4tMqNpHhg">Discussion thread</a></td> 346</tr> 347 348<tr> 349<td>Explicit Conversion Operators</td> 350<td><code>explicit operator <i>type</i>() { 351<br /> // code<br /> }</code></td> 352<td>Allows conversion operators that cannot be implicitly invoked</td> 353<td><a href="http://en.cppreference.com/w/cpp/language/explicit"> 354explicit specifier</a></td> 355<td></td> 356</tr> 357 358<tr> 359<td>Function Suppression</td> 360<td><code><i>Function</i>(<i>arguments</i>) = delete;</code></td> 361<td>Suppresses the implementation of a function, especially a 362synthetic function such as a copy constructor</td> 363<td>TODO: documentation link</td> 364<td><a href="https://groups.google.com/a/chromium.org/forum/#!topic/chromium-dev/i1o7-RNRnMs">Discussion thread</a></td> 365</tr> 366 367<tr> 368<td>(Uniform) Initialization Syntax</td> 369<td><code><i>type</i> <i>name</i> { [<i>value</i> ..., <i>value</i>]};</code></td> 370<td>Allows any object of primitive, aggregate or class 371type to be initialized using brace syntax</td> 372<td>TODO: documentation link</td> 373<td><a href="https://groups.google.com/a/chromium.org/forum/#!topic/chromium-dev/GF96FshwHLw">Discussion thread</a></td> 374</tr> 375 376<tr> 377<td>Inline Namespaces</td> 378<td><code>inline</code></td> 379<td>Allows better versioning of namespaces</td> 380<td><a href="http://en.cppreference.com/w/cpp/language/namespace">Namespaces</a></td> 381<td>Unclear how it will work with components</td> 382</tr> 383 384<tr> 385<td>Lambda Expressions</td> 386<td><code>[<i>captures</i>](<i>params</i>) -> <i>ret</i> { <i>body</i> }</code></td> 387<td>Anonymous functions</td> 388<td><a href="http://en.cppreference.com/w/cpp/language/lambda">Lambda functions</a></td> 389<td>No default captures (<a href="https://google-styleguide.googlecode.com/svn/trunk/cppguide.html#Lambda_expressions">Google Style Guide</a>). <a href="https://groups.google.com/a/chromium.org/forum/#!topic/chromium-dev/D9UnnxBnciQ">Discussion thread</a></td> 390</tr> 391 392<tr> 393<td><code>long long</code> Type</td> 394<td><code>long long <i>var</i>= <i>value</i>;</code></td> 395<td>An integer of at least 64 bits</td> 396<td><a href="http://en.cppreference.com/w/cpp/language/types"> 397Fundamental types</a></td> 398<td><a href="https://groups.google.com/a/chromium.org/forum/#!topic/chromium-dev/RxugZ-pIDxk">Discussion thread</a></td> 399</tr> 400 401<tr> 402<td>Non-Static Class Member Initializers</td> 403<td> 404<code> 405class C {<br /> 406 <i>type</i> <i>var</i> = <i>value</i>;<br/> 407 C() // copy-initializes <i>var</i><br/> 408</code> 409<td>Allows non-static class members to be initialized at their definitions (outside constructors)</td> 410<td><a href="http://en.cppreference.com/w/cpp/language/data_members"> 411Non-static data members</a></td> 412<td><a href="https://groups.google.com/a/chromium.org/forum/#!topic/chromium-dev/zqB-DySA4V0">Discussion thread</a></td> 413</tr> 414 415<tr> 416<td>Raw String Literals</td> 417<td><code>string <i>var</i>=R"(<i>raw_string</i>)";</code></td> 418<td>Allows a string to be encoded without any escape 419sequences, easing parsing in regex expressions, for example</td> 420<td>TODO: documentation link</td> 421<td><a href="https://groups.google.com/a/chromium.org/forum/#!topic/chromium-dev/2kWQHbbuMHI">Discussion thread</a></td> 422</tr> 423 424<tr> 425<td>Union Class Members</td> 426<td><code>union <i>name</i> { <i>class</i> <i>var</i>}</code></td> 427<td>Allows class type members</td> 428<td><a href="http://en.cppreference.com/w/cpp/language/union"> 429Union declarations</a></td> 430<td></td> 431</tr> 432 433<tr> 434<td>User-Defined Literals</td> 435<td><code><i>type</i> <i>var</i> = <i>literal_value</i>_<i>type</i></code></td> 436<td>Allows user-defined literal expressions</td> 437<td>TODO: documentation link</td> 438<td></td> 439</tr> 440 441</tbody> 442</table> 443 444<h3 id="blacklist_stdlib">C++11 Standard Library features</h3> 445 446<details> 447 448<p><summary class="note">All C++11 <strong>Standard Library features are currently 449banned</strong>, because they are not supported on all of our toolchains yet. 450In particular, chromium/android is currently using STLport, and chromium/mac is 451currently using libstdc++4.2, which predate C++11. 452</summary></p> 453 454<table id="banned_stdlib" class="unlined striped"> 455 456<tbody> 457<tr> 458<th style='width:240px;'>Feature</th> 459<th style='width:240px;'>Snippet</th> 460<th style='width:240px;'>Description</th> 461<th style='width:240px;'>Documentation Link</th> 462<th style='width:240px;'>Style Guide Usage</th> 463</tr> 464 465<tr> 466<td>Address Retrieval</td> 467<td><code>std::addressof()</code></td> 468<td>Obtains the address of an object even with overloaded <code>operator&</code></td> 469<td><a href="http://en.cppreference.com/w/cpp/memory/addressof">std::addressof</a></td> 470<td>Usage should be rare as 471<a href="https://google-styleguide.googlecode.com/svn/trunk/cppguide.html#Operator_Overloading"> 472Operator Overloading</a> is rare and <code>&s;</code> 473should suffice in most cases. May be preferable 474over <code>&s;</code> for performing object 475identity checks.</td> 476</tr> 477 478<tr> 479<td>Aligned Storage</td> 480<td><code>std::aligned_storage<Size, Align>::type</code></td> 481<td>Declare uninitialized storage having a specified alignment.</td> 482<td><a href="http://en.cppreference.com/w/cpp/types/aligned_storage">std::aligned_storage</a></td> 483<td>Note: <code>std::aligned_storage</code> is allowed, but some other C++11 484alignment features are still disallowed.</td> 485</tr> 486 487<tr> 488<td>Allocator Traits</td> 489<td><code>std::allocator_traits</code></td> 490<td>Provides an interface for accessing custom allocators</td> 491<td><a href="http://en.cppreference.com/w/cpp/memory/allocator_traits"> 492std::allocator_traits</a></td> 493<td>Usage should be rare.</td> 494</tr> 495 496<tr> 497<td>Atomics</td> 498<td><code>std::atomic</code> and others in <code><atomic></code></td> 499<td>Fine-grained atomic types and operations</td> 500<td><a href="http://en.cppreference.com/w/cpp/atomic"><atomic></a></td> 501<td></td> 502</tr> 503 504<tr> 505<td>Arrays</td> 506<td><code>std::array</code></td> 507<td>A fixed-size replacement for built-in arrays, with STL support</td> 508<td><a href="http://en.cppreference.com/w/cpp/container/array"> 509std::array</a></td> 510<td></td> 511</tr> 512 513<tr> 514<td>Begin and End Non-Member Functions</td> 515<td><code>std::begin()</code> and <code>std::end()</code></td> 516<td>Allows use of free functions on any container, including 517built-in arrays</td> 518<td><a href="http://en.cppreference.com/w/cpp/iterator/begin"> 519std::begin</a> and 520<a href="http://en.cppreference.com/w/cpp/iterator/end"> 521std::end</a></td> 522<td>Useful for built-in arrays.</td> 523</tr> 524 525<tr> 526<td>Bind Operations</td> 527<td><code>std::bind(<i>function</i>, <i>args</i>, ...)</code></td> 528<td>Declares a function object bound to certain arguments</td> 529<td>TODO: documentation link</td> 530<td></td> 531</tr> 532 533<tr> 534<td>C Floating-Point Environment</td> 535<td><code><cfenv></code></td> 536<td>Provides floating point status flags and control modes for C-compatible code</td> 537<td><a href="http://en.cppreference.com/w/cpp/header/cfenv">Standard library header <cfenv></a></td> 538<td>Compilers do not support use</td> 539</tr> 540 541<tr> 542<td>Chrono Library</td> 543<td><code><chrono></code></td> 544<td>Provides a standard date and time library</td> 545<td><a href="http://en.cppreference.com/w/cpp/chrono">Date and time utilities</a></td> 546<td></td> 547</tr> 548 549<tr> 550<td>Complex Inverse Trigonometric and Hyperbolic Functions</td> 551<td>Functions within <code><complex></code></td> 552<td>Adds inverse trigonomentric and hyperbolic non-member functions to 553the <code><complex></code> library.</td> 554<td><a href="http://en.cppreference.com/w/cpp/numeric/complex">std::complex</a></td> 555<td></td> 556</tr> 557 558<tr> 559<td>Conditional Type Selection</td> 560<td><code>std::enable_if</code> and <code>std::conditional</code></td> 561<td>Enables compile-time conditional type selection</td> 562<td><a href="http://en.cppreference.com/w/cpp/types/enable_if"> 563std::enable_if</a> and 564<a href="http://en.cppreference.com/w/cpp/types/conditional"> 565conditional</a></td> 566<td></td> 567</tr> 568 569<tr> 570<td>Constant Iterator Methods on Containers</td> 571<td><code>std::cbegin()</code> and <code>std::cend()</code></td> 572<td>Enforces iteration methods that don't change container contents</td> 573<td>TODO: documentation link</td> 574<td></td> 575</tr> 576 577<tr> 578<td>Construct Elements in Containers</td> 579<td><code>emplace()</code>,<code>emplace_back()</code>, 580<code>emplace_front()</code>, <code>emplace_hint()</code></td> 581<td>Constructs elements directly within a container without a copy 582or a move</td> 583<td>TODO: documentation link</td> 584<td>Use where element construction within a container 585is needed.</td> 586</tr> 587 588<tr> 589<td>Container Compaction Functions</td> 590<td><code>std::vector::shrink_to_fit()</code>, 591<code>std::deque::shrink_to_fit()</code>, and 592<code>std::string::shrink_to_fit()</code></td> 593<td>Requests the removal of unused space 594in the container</td> 595<td><a href="http://en.cppreference.com/w/cpp/container/vector/shrink_to_fit"> 596std::vector::shrink_to_fit</a>, 597<a href="http://en.cppreference.com/w/cpp/container/deque/shrink_to_fit"> 598std::deque::shrink_to_fit</a>, and 599<a href="http://en.cppreference.com/w/cpp/string/basic_string/shrink_to_fit"> 600std::basic_string::shrink_to_fit</a></td> 601<td></td> 602</tr> 603 604<tr> 605<td>Date/Time String Formatting Specifiers</td> 606<td><code>std::strftime()</code></td> 607<td>Converts date and time information into a 608formatted string using new specifiers</td> 609<td><a href="http://en.cppreference.com/w/cpp/chrono/c/strftime"> 610std::strftime</a></td> 611<td></td> 612</tr> 613 614<tr> 615<td>Function Return Type Deduction</td> 616<td><code>std::result_of<<i>Functor(ArgTypes...)</i>></code></td> 617<td>Extracts the return type from the type signature of 618a function call invocation at compile-time.</td> 619<td><a href="http://en.cppreference.com/w/cpp/types/result_of"> 620std::result_of</a></td> 621<td> 622<a href="http://stackoverflow.com/questions/15486951/why-does-stdresult-of-take-an-unrelated-function-type-as-a-type-argument"> 623Why does std::result_of take an (unrelated) function type as a type argument? 624</a></td> 625</tr> 626 627<tr> 628<td>Function Objects</td> 629<td><code>std::function</code></td> 630<td>Wraps a standard polymorphic function</td> 631<td>TODO: documentation link</td> 632<td></td> 633</tr> 634 635<tr> 636<td>Forward Lists</td> 637<td><code>std::forward_list</code></td> 638<td>Provides an efficient singly linked list</td> 639<td><a href="http://en.cppreference.com/w/cpp/container/forward_list"> 640std::forward_list</a></td> 641<td></td> 642</tr> 643 644<tr> 645<td>Gamma Natural Log</td> 646<td><code>std::lgamma()</code></td> 647<td>Computes the natural log of the gamma of a 648floating point value</td> 649<td><a href="http://en.cppreference.com/w/cpp/numeric/math/lgamma"> 650std::lgamma</a></td> 651<td></td> 652</tr> 653 654<tr> 655<td>Garbage Collection Features</td> 656<td><code>std::{un}declare_reachable()</code> and 657<code>std::{un}declare_no_pointers()</code></td> 658<td>Enables garbage collection implementations</td> 659<td><a href="http://en.cppreference.com/w/cpp/memory/gc/declare_reachable"> 660std::declare_reachable</a> 661and <a href="http://en.cppreference.com/w/cpp/memory/gc/declare_no_pointers"> 662std::declare_no_pointers</a></td> 663<td></td> 664</tr> 665 666<tr> 667<td>Heap Validation</td> 668<td><code>std::is_heap()</code></td> 669<td>Checks whether an iterator range is in fact a heap</td> 670<td>TODO: documentation link</td> 671<td></td> 672</tr> 673 674<tr> 675<td>Is Nan</td> 676<td><code>std::isnan()</code></td> 677<td>Determines if a floating point value is not-a-number</td> 678<td><a href="http://en.cppreference.com/w/cpp/numeric/math/isnan">std::isnan</a></td> 679<td></td> 680</tr> 681 682<tr> 683<td>Iterator Operators</td> 684<td><code>std::next()</code> and <code>std::prev()</code></td> 685<td>Copies an iterator and increments or decrements the copy by 686some value</td> 687<td><a href="http://en.cppreference.com/w/cpp/iterator/next">std::next</a> 688and <a href="http://en.cppreference.com/w/cpp/iterator/prev">std::prev</a> 689</td> 690<td></td> 691</tr> 692 693<tr> 694<td>Initializer Lists</td> 695<td><code>std::initializer_list<T></code></td> 696<td>Allows containers to be initialized with aggregate elements</td> 697<td>TODO: documentation link</td> 698<td></td> 699</tr> 700 701<tr> 702<td>Move Semantics</td> 703<td><code>std::move()</code></td> 704<td>Facilitates efficient move operations</td> 705<td><a href="http://en.cppreference.com/w/cpp/utility/move"> 706<code>std::move</code> reference</a></td> 707<td></td> 708</tr> 709 710<tr> 711<td>Pointer Traits Class Template</td> 712<td><code>std::pointer_traits</code></td> 713<td>Provides a standard way to access properties 714of pointers and pointer-like types</td> 715<td><a href="http://en.cppreference.com/w/cpp/memory/pointer_traits"> 716std::pointer_traits</a></td> 717<td>Useful for determining the element type 718pointed at by a (possibly smart) pointer.</td> 719</tr> 720 721<tr> 722<td>Random Number Generators</td> 723<td>Functions within <code><random></code></td> 724<td>Random number generation algorithms and utilities</td> 725<td><a href="http://en.cppreference.com/w/cpp/numeric/random"> 726Pseudo-random number generation</a></td> 727<td></td> 728</tr> 729 730<tr> 731<td>Ratio Template Class</td> 732<td><code>std::ratio<<i>numerator</i>, <i>denominator</i>></code></td> 733<td>Provides compile-time rational numbers</td> 734<td>TODO: documentation link</td> 735<td></td> 736</tr> 737 738<tr> 739<td>Reference Wrapper Classes</td> 740<td><code>std::reference_wrapper</code> and 741<code>std::ref()</code>, <code>std::cref()</code></td> 742<td>Allows you to wrap a reference within a standard 743object (and use those within containers)</td> 744<td><a href="http://www.informit.com/guides/content.aspx?g=cplusplus&seqNum=217"> 745Reference Wrappers</a></td> 746<td></td> 747</tr> 748 749<tr> 750<td>Regex Library</td> 751<td><code><regex></code></td> 752<td>Provides a standard regular expressions library</td> 753<td><a href="http://en.cppreference.com/w/cpp/regex">Regular expressions library</a></td> 754<td></td> 755</tr> 756 757<tr> 758<td>Shared Pointers</td> 759<td><code>std::shared_ptr</code></td> 760<td>Allows shared ownership of a pointer through reference counts</td> 761<td><a href="http://en.cppreference.com/w/cpp/memory/shared_ptr">std::shared_ptr</a></td> 762<td><a href="https://google-styleguide.googlecode.com/svn/trunk/cppguide.html#Ownership_and_Smart_Pointers"> 763Ownership and Smart Pointers</a></td> 764</tr> 765 766<tr> 767<td>Soft Program Exits</td> 768<td><code>std::at_quick_exit()</code> 769and <code>std::quick_exit()</code></td> 770<td>Allows registration of functions to be called upon exit, 771allowing cleaner program exit than <code>abort()</code> or 772<code>exit</code></td> 773<td><a href="http://en.cppreference.com/w/cpp/utility/program/quick_exit"> 774std:quick_exit</a></td> 775<td></td> 776</tr> 777 778<tr> 779<td>String Direct Reference Functions</td> 780<td><code>std::string::front()</code> and <code>std::string::back()</code></td> 781<td>Returns a reference to the front or back of a string</td> 782<td><a href="http://en.cppreference.com/w/cpp/string/basic_string/front"> 783std::basic_string::front</a> and 784<a href="http://en.cppreference.com/w/cpp/string/basic_string/back"> 785std::basic_string::back</a></td> 786<td></td> 787</tr> 788 789<tr> 790<td>String to Number Functions</td> 791<td><code>std::stoi()</code>, <code>std::stol()</code>, 792<code>std::stoul()</code>, <code>std::stoll</code>, <code>std::stoull()</code>, 793<code>std::stof()</code>, <code>std::stod()</code>, <code>std::stold()</code>, 794and <code>std::to_string()</code></td> 795<td>Converts strings to numbers</td> 796<td><a href="http://en.cppreference.com/w/cpp/string/basic_string/stol"> 797std::stoi, std::stol, std::stoll</a>, 798<a href="http://en.cppreference.com/w/cpp/string/basic_string/stoul"> 799std::stoul, std::stoull</a>, and 800<a href="http://en.cppreference.com/w/cpp/string/basic_string/stof"> 801std::stof, std::stod, std::stold</a> </td> 802<td></td> 803</tr> 804 805<tr> 806<td>STL Algorithms</td> 807<td>Functions within <code><algorithm></code>.</td> 808<td>Enhancements to the set of STL algorithms</td> 809<td>See the <a href="http://en.cppreference.com/w/cpp/algorithm"> 810Algorithms library</a> for a complete list.</td> 811<td></td> 812</tr> 813 814<tr> 815<td>System Errors</td> 816<td><code><system_error></code></td> 817<td>Provides a standard system error library</td> 818<td><a href="http://en.cppreference.com/w/cpp/error/system_error">std::system_error</a></td> 819<td></td> 820</tr> 821 822<tr> 823<td>Trailing Return Types</td> 824<td><code>auto <i>function declaration</i> -> <i>return_type</i></code></td> 825<td>Allows trailing function return value syntax</td> 826<td><a href="http://en.cppreference.com/w/cpp/language/function"> 827Declaring functions</a></td> 828<td><a href="https://groups.google.com/a/chromium.org/forum/#!topic/chromium-dev/OQyYSfH9m2M">Discussion thread</a></td> 829</tr> 830 831<tr> 832<td>Thread Library</td> 833<td><code><thread> support, including <future>, 834<mutex>, <condition_variable></code></td> 835<td>Provides a standard mulitthreading library using <code>std::thread</code> and associates</td> 836<td><a href="http://en.cppreference.com/w/cpp/thread">Thread support library</a></td> 837<td></td> 838</tr> 839 840<tr> 841<td>Tuples</td> 842<td><code>std::tuple</code></td> 843<td>A fixed-size ordered collection of values of mixed types</td> 844<td>TODO: documentation link</td> 845<td></td> 846</tr> 847 848<tr> 849<td>Type-Generic Math Functions</td> 850<td>Functions within <code><ctgmath></code></td> 851<td>Provides a means to call real or complex functions 852based on the type of arguments</td> 853<td><a href="http://en.cppreference.com/w/cpp/header/ctgmath"> 854Standard library header <ctgmath></a></td> 855<td></td> 856</tr> 857 858<tr> 859<td>Type Info Enhancements</td> 860<td><code>std::type_index</code> and <code>std::type_info::hash_code()</code></td> 861<td>Allows type information (most often within containers) 862that can be copied, assigned, or hashed</td> 863<td><a href="http://en.cppreference.com/w/cpp/types/type_index"> 864std::type_index</a> and 865<a href="http://en.cppreference.com/w/cpp/types/type_info/hash_code"> 866std::type_info::hash_code</a></td> 867<td><code>std::type_index</code> is a thin wrapper for 868<code>std::type_info</code>, allowing you to use it directly 869within both associative and unordered containers</td> 870</tr> 871 872<tr> 873<td>Type Traits</td> 874<td>Class templates within <code><type_traits></code></td> 875<td>Allows compile-time inspection of the properties of types</td> 876<td><a href="http://en.cppreference.com/w/cpp/header/type_traits"> 877Standard library header <type_traits></a></td> 878<td></td> 879</tr> 880 881<tr> 882<td>Unique Pointers</td> 883<td><code>std::unique_ptr<<i>type</i>></code></td> 884<td>Defines a pointer with clear and unambiguous ownership</td> 885<td>TODO: documentation link</td> 886<td><a href="https://google-styleguide.googlecode.com/svn/trunk/cppguide.html#Ownership_and_Smart_Pointers"> 887Ownership and Smart Pointers</a></td> 888</tr> 889 890<tr> 891<td>Unordered Associative Containers</td> 892<td><code>std::unordered_set</code>, <code>std::unordered_map</code>, 893<code>std::unordered_multiset</code>, and <code>std::unordered_multimap</code></td> 894<td>Allows efficient containers of key/value pairs</td> 895<td><a href="http://en.cppreference.com/w/cpp/container/unordered_map">std::unordered_map</a> 896and <a href="http://en.cppreference.com/w/cpp/container/unordered_set">std::unordered_set</a> 897</td> 898<td></td> 899</tr> 900 901<tr> 902<td>Variadic Copy Macro</td> 903<td><code>va_copy(va_list <i>dest</i>, va_list <i>src</i>)</code></td> 904<td>Makes a copy of the variadic function arguments</td> 905<td></td> 906<td></td> 907</tr> 908 909<tr> 910<td>Weak Pointers</td> 911<td><code>std::weak_ptr</code></td> 912<td>Allows a weak reference to a <code>std::shared_ptr</code></td> 913<td><a href="http://en.cppreference.com/w/cpp/memory/weak_ptr"> 914std::weak_ptr</a></td> 915<td><a href="https://google-styleguide.googlecode.com/svn/trunk/cppguide.html#Ownership_and_Smart_Pointers"> 916Ownership and Smart Pointers</a></td> 917</tr> 918 919<tr> 920<td>Wide String Support</td> 921<td><code>std::wstring_convert</code>, 922<code>std::wbuffer_convert</code>. 923<code>std::codecvt_utf8</code>, <code>std::codecvt_utf16</code>, 924and <code>std::codecvt_utf8_utf16</code></td> 925<td>Converts between string encodings</td> 926<td><a href="http://en.cppreference.com/w/cpp/locale/wstring_convert"> 927std::wstring_convert</a>, 928<a href="http://en.cppreference.com/w/cpp/locale/wbuffer_convert"> 929std::wbuffer_convert</a>, 930<a href="http://en.cppreference.com/w/cpp/locale/codecvt_utf8"> 931std::codecvt_utf8</a>, 932<a href="http://en.cppreference.com/w/cpp/locale/codecvt_utf16"> 933std::codecvt_utf16</a>, and 934<a href="http://en.cppreference.com/w/cpp/locale/codecvt_utf8_utf16"> 935std::codecvt_utf8_utf16</a> 936</td> 937<td>Non-UTF-8 text is banned by the 938<a href="https://google-styleguide.googlecode.com/svn/trunk/cppguide.html#Non-ASCII_Characters"> 939C++ Style Guide</a>. However, may be useful for 940consuming non-ASCII data.</td> 941</tr> 942 943</tbody> 944</table> 945 946</details> 947 948</div> 949</body> 950</html> 951