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| <title>C++11 use in Chromium</title> |
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| <h1>C++11 use in Chromium</h1> |
| |
| <p><i>This document lives at src/styleguide/c++/c++11.html in a Chromium |
| checkout.</i></p> |
| |
| <p>This document summarizes the features of C++11 (both in the language itself |
| and in enhancements to the Standard Library) and describes which features are |
| allowed in Chromium and contains pointers to more detailed information. The |
| Guide applies to Chromium and its subprojects. Subprojects can choose to be |
| more restrictive if they need to compile on more toolchains than Chromium.</p> |
| |
| <p>You can propose to make a feature available or to ban a |
| feature by sending an email to chromium-dev. Ideally include a short blurb |
| on what the feature is, and why you think it should or should not be allowed. |
| Ideally, the list will arrive at some consensus and the wiki page will be |
| updated to mention that consensus. If there's no consensus, |
| <code>src/styleguide/C++/OWNERS</code> get to decide -- for divisive features, we expect |
| the decision to be to not use the feature yet and possibly discuss it again a |
| few months later, when we have more experience with the language.</p> |
| |
| <p class="warning">Unless otherwise noted, <strong>no</strong> C++11 |
| <strong>library</strong> features are allowed.</p> |
| |
| <h2 id="whitelist">C++11 Allowed Features</h2> |
| |
| <p>The following features are currently allowed.</p> |
| |
| <table id="whitelist_lang_list" class="unlined striped"> |
| <tbody> |
| |
| <tr> |
| <th style='width:220px;'>Feature</th> |
| <th style='width:260px;'>Snippet</th> |
| <th style='width:240px;'>Description</th> |
| <th style='width:240px;'>Documentation Link</th> |
| <th style='width:240px;'>Notes and Discussion Thread</th> |
| </tr> |
| |
| <tr> |
| <td>Aliases</td> |
| <td><code>using <i>new_alias</i> = <i>typename</i></code></td> |
| <td>Allow parameterized typedefs</td> |
| <td><a href="http://en.cppreference.com/w/cpp/language/type_alias">Type alias (using syntax)</a></td> |
| <td>Use instead of typedef, unless the header needs to be compatible with C. <a href="https://groups.google.com/a/chromium.org/forum/#!topic/chromium-dev/8dOAMzgR4ao">Discussion thread</a></td> |
| </tr> |
| |
| <tr> |
| <td>Angle Bracket Parsing in Templates</td> |
| <td><code>>></code> for <code>> ></code> and <br /> |
| <code><::</code> for <code>< ::</code></td> |
| <td>More intuitive parsing of template parameters</td> |
| <td><a href="http://stackoverflow.com/questions/15785496/c-templates-angle-brackets-pitfall-what-is-the-c11-fix"> |
| C++ Templates Angle Brackets Pitfall</a></td> |
| <td>Recommended to increase readability. Approved without discussion.</td> |
| </tr> |
| |
| <tr> |
| <td>Automatic Types</td> |
| <td><code>auto</code></td> |
| <td>Automatic type deduction</td> |
| <td>TODO: documentation link</td> |
| <td>Use according to the <a |
| href="https://google-styleguide.googlecode.com/svn/trunk/cppguide.html#auto">Google |
| Style Guide on <code>auto</code></a>. <a href="https://groups.google.com/a/chromium.org/forum/#!topic/chromium-dev/OQyYSfH9m2M">Discussion thread</a>. <a href="https://groups.google.com/a/chromium.org/forum/#!topic/chromium-dev/5-Bt3BJzAo0">Another discussion thread</a>.</td> |
| </tr> |
| |
| <tr> |
| <td>Declared Type Accessor</td> |
| <td><code>decltype(<i>expression</i>)</code></td> |
| <td>Provides a means to determine the type of an expression at compile-time, |
| useful most often in templates.</td> |
| <td><a href="http://en.cppreference.com/w/cpp/language/decltype"> |
| decltype specifier</a></td> |
| <td>Usage should be rare. <a href="https://groups.google.com/a/chromium.org/forum/#!topic/chromium-dev/_zoNvZd_dSo">Discussion thread</a></td> |
| </tr> |
| |
| <tr> |
| <td>Default Function Creation</td> |
| <td><code><i>Function</i>(<i>arguments</i>) = default;</code></td> |
| <td>Instructs the compiler to generate a default version |
| of the indicated function</td> |
| <td><a href="http://stackoverflow.com/questions/823935/whats-the-point-in-defaulting-functions-in-c11"> |
| What's the point in defaulting functions in C++11?</a></td> |
| <td>Doesn't work for move constructors and move assignment operators in MSVC2013. |
| <a href="https://groups.google.com/a/chromium.org/forum/#!topic/chromium-dev/qgU4mh_MpGA">Discussion thread</a></td> |
| </tr> |
| |
| <tr> |
| <td>Delegated Constructors</td> |
| <td><code>Class() : Class(0) {}</code><br /> |
| <code>Class(<i>type</i> <i>var</i>) : Class(<i>var</i>, 0)</code></td> |
| <td>Allow overloaded constructors to use common initialization code</td> |
| <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"> |
| Introduction to the C++11 feature: delegating constructors</a></td> |
| <td><a href="https://groups.google.com/a/chromium.org/forum/#!topic/chromium-dev/0zVA8Ctx3Xo">Discussion thread</a></td> |
| </tr> |
| |
| <tr> |
| <td>Enumerated Type Classes and Enum Bases</td> |
| <td><code>enum class <i>classname</i></code><br> |
| <code>enum class <i>classname</i> : <i>base-type</i></code><br> |
| <code>enum <i>enumname</i> : <i>base-type</i></code></td> |
| <td>Provide enums as full classes, with no implicit |
| conversion to booleans or integers. Provide an explicit underlying type for |
| enum classes and regular enums.</td> |
| <td><a href="http://www.stroustrup.com/C++11FAQ.html#enum">enum-class</a></td> |
| <td>Enum classes are still enums and follow enum naming rules |
| (which means SHOUTY_CASE in the <a href="http://www.chromium.org/developers/coding-style#Naming">current style guide</a>). |
| <a href="https://groups.google.com/a/chromium.org/forum/#!topic/chromium-dev/Q5WmkAImanc">Discussion thread</a></td> |
| </tr> |
| |
| <tr> |
| <td>Final Specifier</td> |
| <td><code>final</code></td> |
| <td> Indicates that a class or function is final and cannot be overridden</td> |
| <td><a href="http://en.cppreference.com/w/cpp/language/final">final Language Reference</a></td> |
| <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> |
| </tr> |
| |
| <tr> |
| <td>Function Suppression</td> |
| <td><code><i>Function</i>(<i>arguments</i>) = delete;</code></td> |
| <td>Suppresses the implementation of a function, especially a |
| synthetic function such as a copy constructor</td> |
| <td>TODO: documentation link</td> |
| <td><a href="https://groups.google.com/a/chromium.org/forum/#!topic/chromium-dev/i1o7-RNRnMs">Discussion thread</a></td> |
| </tr> |
| |
| <tr> |
| <td>Lambda Expressions</td> |
| <td><code>[<i>captures</i>](<i>params</i>) -> <i>ret</i> { <i>body</i> }</code></td> |
| <td>Anonymous functions</td> |
| <td><a href="http://en.cppreference.com/w/cpp/language/lambda">Lambda functions</a></td> |
| <td>Do not bind or store lambdas; use <code>base::Bind</code> and |
| <code>base::Callback</code> instead, because they offer protection against a |
| large class of object lifetime mistakes. Don't use default captures |
| (<code>[=]</code>, <code>[&]</code> – <a |
| href="https://google-styleguide.googlecode.com/svn/trunk/cppguide.html#Lambda_expressions">Google Style Guide</a>). |
| Lambdas are typically useful as a parameter to methods or |
| functions that will use them immediately, such as those in |
| <code><algorithm></code>. <a |
| href="https://groups.google.com/a/chromium.org/forum/#!topic/chromium-dev/D9UnnxBnciQ">Discussion |
| thread</a></td> |
| </tr> |
| |
| <tr> |
| <td>Local Types as Template Arguments</td> |
| <td></td> |
| <td>Allows local and unnamed types as template arguments</td> |
| <td><a href="http://stackoverflow.com/questions/742607/using-local-classes-with-stl-algorithms"> |
| Local types, types without linkage and unnamed types as template arguments</a></td> |
| <td>Usage should be rare. Approved without discussion.</td> |
| </tr> |
| |
| <tr> |
| <td>Non-Static Class Member Initializers</td> |
| <td> |
| <code> |
| class C {<br /> |
| <i>type</i> <i>var</i> = <i>value</i>;<br/> |
| C() // copy-initializes <i>var</i><br/> |
| </code> |
| <td>Allows non-static class members to be initialized at their definitions (outside constructors)</td> |
| <td><a href="http://en.cppreference.com/w/cpp/language/data_members"> |
| Non-static data members</a></td> |
| <td><a href="https://google-styleguide.googlecode.com/svn/trunk/cppguide.html#Initialization">Google |
| Style Guide</a>. |
| <a href="https://groups.google.com/a/chromium.org/forum/#!topic/chromium-dev/zqB-DySA4V0">Discussion thread</a> |
| </td> |
| </tr> |
| |
| <tr> |
| <td>Null Pointer Constant</td> |
| <td><code>nullptr</code></td> |
| <td>Declares a type-safe null pointer</td> |
| <td>TODO: documentation link</td> |
| <td>Recommended for new code. |
| <a href="https://groups.google.com/a/chromium.org/forum/#!topic/chromium-dev/4mijeJHzxLg">Discussion thread</a>. |
| <a href="https://google-styleguide.googlecode.com/svn/trunk/cppguide.html#0_and_nullptr/NULL">Google Style Guide</a>. |
| Note: <code>std::nullptr_t</code> is a library feature and not available. |
| </td> |
| </tr> |
| |
| <tr> |
| <td>Override Specifier</td> |
| <td><code>override</code></td> |
| <td>Indicates that a class or function overrides a base implementation</td> |
| <td><a href="http://en.cppreference.com/w/cpp/language/override">override Language Reference</a></td> |
| <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> |
| </tr> |
| |
| <tr> |
| <td>Range-Based For Loops</td> |
| <td><code>for (<i>type</i> <i>var</i> : <i>range</i>)</code></td> |
| <td>Facilitates a more concise syntax for iterating over the elements |
| of a container (or a range of iterators) in a <code>for</code> loop</td> |
| <td>TODO: documentation link</td> |
| <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> |
| </tr> |
| |
| <tr> |
| <td>Standard Integers</td> |
| <td>Typedefs within <code><stdint.h></code> |
| and <code><inttypes></code></td> |
| <td>Provides fixed-size integers independent of platforms</td> |
| <td><a href="http://www.cplusplus.com/reference/cstdint/"> |
| <stdint.h> (cstdint)</a></td> |
| <td>Already in common use in the codebase. Approved without discussion.</td> |
| </tr> |
| |
| <tr> |
| <td>Static Assertions</td> |
| <td><code>static_assert(<i>bool</i>, <i>string</i>)</code></td> |
| <td>Tests compile-time conditions</td> |
| <td><a href="http://en.cppreference.com/w/cpp/language/static_assert">Static Assertion</a></td> |
| <td><a href="https://groups.google.com/a/chromium.org/forum/#!topic/chromium-dev/POISBQEhGzU">Discussion thread</a></td> |
| </tr> |
| |
| <tr> |
| <td>Variadic Macros</td> |
| <td><code>#define <i>MACRO</i>(...) <i>Impl</i>(<i>args</i>, __VA_ARGS__)</code></td> |
| <td>Allows macros that accept a variable number of arguments</td> |
| <td><a href="http://stackoverflow.com/questions/4786649/are-variadic-macros-nonstandard"> |
| Are Variadic macros nonstandard?</a></td> |
| <td>Usage should be rare. <a href="https://groups.google.com/a/chromium.org/forum/#!topic/chromium-dev/sRx9j3CQqyA">Discussion thread</a></td> |
| </tr> |
| |
| <tr> |
| <td>Variadic Templates</td> |
| <td><code>template <<i>typename</i> ... <i>arg</i>></code></td> |
| <td>Allows templates that accept a variable number of arguments</td> |
| <td>TODO: documentation link</td> |
| <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> |
| </tr> |
| |
| </tbody> |
| </table> |
| |
| <h2 id="blacklist">C++11 Blacklist (Disallowed and Banned Features)</h2> |
| |
| <p>This section lists features that are not allowed to be used yet. |
| |
| <h3 id="blacklist_banned">C++11 Banned Features</h3> |
| |
| <p>This section lists C++11 features that are not allowed in the Chromium |
| codebase. |
| </p> |
| |
| <table id="banned_list" class="unlined striped"> |
| <tbody> |
| |
| <tr> |
| <th style='width:240px;'>Feature or Library</th> |
| <th style='width:240px;'>Snippet</th> |
| <th style='width:240px;'>Description</th> |
| <th style='width:240px;'>Documentation Link</th> |
| <th style='width:240px;'>Notes</th> |
| </tr> |
| |
| <tr> |
| <td>Constant Expressions</td> |
| <td><code>constexpr</code></td> |
| <td>Compile-time constant expressions</td> |
| <td>TODO: documentation link</td> |
| <td>Doesn't work in MSVS2013. Reevalute once it does. <a |
| href="https://google-styleguide.googlecode.com/svn/trunk/cppguide.html#Use_of_constexpr">Google |
| Style Guide on <code>constexpr</code></a></td> |
| </tr> |
| |
| <tr> |
| <td>Explicit Conversion Operators</td> |
| <td><code>explicit operator <i>type</i>() { |
| <br /> // code<br /> }</code></td> |
| <td>Allows conversion operators that cannot be implicitly invoked</td> |
| <td><a href="http://en.cppreference.com/w/cpp/language/explicit"> |
| explicit specifier</a></td> |
| <td><a href="https://connect.microsoft.com/VisualStudio/feedback/details/811334/bug-in-vs-2013-support-for-explicit-conversion-operators">Doesn't work in MSVS2013</a>. Reevaluate once it does. <a href="https://groups.google.com/a/chromium.org/d/msg/chromium-dev/zGF1SrQ-1HQ/BAiC12vwPeEJ">Discussion thread</a></td> |
| </tr> |
| |
| <tr> |
| <td>Function Local Variable</td> |
| <td><code>__func__</code></td> |
| <td>Provides a local variable of the name of the enclosing |
| function for logging purposes</td> |
| <td><a href="http://www.informit.com/guides/content.aspx?g=cplusplus&seqNum=338"> |
| The __func__ Predeclared Identifier is Coming to C++</a></td> |
| <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> |
| </tr> |
| |
| <tr> |
| <td>Inherited Constructors</td> |
| <td><code>class Derived : Base { |
| <br /> using Base::Base; |
| <br />};</code></td> |
| <td>Allow derived classes to inherit constructors from base classes</td> |
| <td><a href="http://en.cppreference.com/w/cpp/language/using_declaration">Using-declaration</a></td> |
| <td>Doesn't work in MSVS2013. Reevaluate once it does. <a |
| href="https://groups.google.com/a/chromium.org/d/msg/chromium-dev/BULzgIKZ-Ao/PLO7_GoVNvYJ">Discussion thread</a></td> |
| </tr> |
| |
| <tr> |
| <td><code>long long</code> Type</td> |
| <td><code>long long <i>var</i>= <i>value</i>;</code></td> |
| <td>An integer of at least 64 bits</td> |
| <td><a href="http://en.cppreference.com/w/cpp/language/types"> |
| Fundamental types</a></td> |
| <td>Use an stdint.h type if you need a 64bit number. <a href="https://groups.google.com/a/chromium.org/forum/#!topic/chromium-dev/RxugZ-pIDxk">Discussion thread</a></td> |
| </tr> |
| |
| <tr> |
| <td>Raw String Literals</td> |
| <td><code>string <i>var</i>=R"(<i>raw_string</i>)";</code></td> |
| <td>Allows a string to be encoded without any escape |
| sequences, easing parsing in regex expressions, for example</td> |
| <td>TODO: documentation link</td> |
| <td>Causes incorrect line numbers in MSVS2014 and gcc. Reevaluate once that works. <a href="https://groups.google.com/a/chromium.org/forum/#!topic/chromium-dev/2kWQHbbuMHI">Discussion thread</a></td> |
| </tr> |
| |
| <tr> |
| <td>Rvalue References (and Move Semantics)</td> |
| <td><code>T(T&& t)</code> and <code>T& operator=(T&& t)</code></td> |
| <td>Reference that only binds to a temporary object</td> |
| <td>TODO: documentation link</td> |
| <td>To be revisited in the future. Allowed in exceptional cases where approved by the OWNERS of src/styleguide/c++/.</td> |
| </tr> |
| |
| <tr> |
| <td>(Uniform) Initialization Syntax</td> |
| <td><code><i>type</i> <i>name</i> { [<i>value</i> ..., <i>value</i>]};</code></td> |
| <td>Allows any object of primitive, aggregate or class |
| type to be initialized using brace syntax</td> |
| <td>TODO: documentation link</td> |
| <td>Dangerous without library support, see thread. Reevaulate once we have C++11 library support. <a href="https://groups.google.com/a/chromium.org/forum/#!topic/chromium-dev/GF96FshwHLw">Discussion thread</a></td> |
| </tr> |
| |
| <tr> |
| <td>UTF-16 and UTF-32 Support (16-Bit and 32-Bit Character Types)</td> |
| <td><code>char16_t</code> and <code>char32_t</code></td> |
| <td>Provides character types for handling 16-bit |
| and 32-bit code units (useful for encoding |
| UTF-16 and UTF-32 string data)</td> |
| <td><a href="http://en.cppreference.com/w/cpp/language/types"> |
| Fundamental types</a></td> |
| <td>Doesn't work in MSVS2013. Reevaluate once it does. Non-UTF-8 text is |
| banned by the |
| <a href="https://google-styleguide.googlecode.com/svn/trunk/cppguide.html#Non-ASCII_Characters"> |
| C++ Style Guide</a>. However, may be useful for |
| consuming non-ASCII data. <a href="https://groups.google.com/a/chromium.org/forum/#!topic/chromium-dev/ME2kL7_Kvyk">Discussion thread</a></td> |
| </tr> |
| |
| <tr> |
| <td>UTF-8, UTF-16, UTF-32 String Literals</td> |
| <td><code>u8"<i>string</i>", u"<i>string</i>", U"<i>string</i>"</code></td> |
| <td>Enforces UTF-8, UTF-16, UTF-32 encoding on all string literals</td> |
| <td><a href="http://en.cppreference.com/w/cpp/language/string_literal"> |
| string literal</a></td> |
| <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> |
| </tr> |
| |
| </tbody> |
| </table> |
| |
| <h3 id="blacklist_review">C++11 Features To Be Discussed</h3> |
| |
| <p>The following C++ language features are currently disallowed. |
| See the top of this page on how to propose moving a feature from this list |
| into the allowed or banned sections. Note that not all of these features |
| work in all our compilers yet.</p> |
| |
| <table id="blacklist_review_list" class="unlined striped"> |
| <tbody> |
| |
| <tr> |
| <th style='width:240px;'>Feature</th> |
| <th style='width:240px;'>Snippet</th> |
| <th style='width:240px;'>Description</th> |
| <th style='width:240px;'>Documentation Link</th> |
| <th style='width:240px;'>Notes</th> |
| </tr> |
| |
| <tr> |
| <td>Alignment Features</td> |
| <td> |
| <code>alignas</code> specifier, |
| <code>std::alignment_of<T></code>, |
| <code>std::aligned_union<Size, ...Types></code> and |
| <code>std::max_align_t</code></td> |
| <td>Object alignment</td> |
| <td><a href="http://en.cppreference.com/w/cpp/types/alignment_of">std::alignment_of</a></td> |
| <td></td> |
| </tr> |
| |
| <tr> |
| <td>Attributes</td> |
| <td><code>[[<i>attribute_name</i>]]</code></td> |
| <td>Attaches properties to declarations that |
| specific compiler implementations may use.</td> |
| <td><a href="http://www.codesynthesis.com/~boris/blog/2012/04/18/cxx11-generalized-attributes/"> |
| C++11 generalized attributes</a></td> |
| <td></td> |
| </tr> |
| |
| <tr> |
| <td>Default Function Template Arguments</td> |
| <td><code>template <typename T = <i>type</i>> <br /> |
| <i>type</i> <i>Function</i>(T <i>var</i>) {}</code></td> |
| <td>Allow function templates, like classes, to have default arguments</td> |
| <td><a href="http://stackoverflow.com/questions/2447458/default-template-arguments-for-function-templates"> |
| Default Template Arguments for Function Templates</a></td> |
| <td></td> |
| </tr> |
| |
| <tr> |
| <td>Exception Features</td> |
| <td><code>noexcept</code>, <code>exception_ptr</code>, |
| <code>current_exception()</code>, <code>rethrow_exception</code>, |
| and <code>nested_exception</code></td> |
| <td>Enhancements to exception throwing and handling</td> |
| <td><a href="http://en.cppreference.com/w/cpp/error/exception"> |
| std::exception</a></td> |
| <td>Exceptions are banned by the |
| <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> |
| </tr> |
| |
| <tr> |
| <td>Inline Namespaces</td> |
| <td><code>inline</code></td> |
| <td>Allows better versioning of namespaces</td> |
| <td><a href="http://en.cppreference.com/w/cpp/language/namespace">Namespaces</a></td> |
| <td>Unclear how it will work with components</td> |
| </tr> |
| |
| <tr> |
| <td>Union Class Members</td> |
| <td><code>union <i>name</i> { <i>class</i> <i>var</i>}</code></td> |
| <td>Allows class type members</td> |
| <td><a href="http://en.cppreference.com/w/cpp/language/union"> |
| Union declarations</a></td> |
| <td></td> |
| </tr> |
| |
| <tr> |
| <td>User-Defined Literals</td> |
| <td><code><i>type</i> <i>var</i> = <i>literal_value</i>_<i>type</i></code></td> |
| <td>Allows user-defined literal expressions</td> |
| <td>TODO: documentation link</td> |
| <td></td> |
| </tr> |
| |
| </tbody> |
| </table> |
| |
| <h3 id="blacklist_stdlib">C++11 Standard Library features</h3> |
| |
| <details> |
| |
| <p><summary class="note">All C++11 <strong>Standard Library features are currently |
| banned</strong>, because they are not supported on all of our toolchains yet. |
| In particular, chromium/android is currently using STLport, and chromium/mac is |
| currently using libstdc++4.2, which predate C++11. |
| </summary></p> |
| |
| <table id="banned_stdlib" class="unlined striped"> |
| |
| <tbody> |
| <tr> |
| <th style='width:240px;'>Feature</th> |
| <th style='width:240px;'>Snippet</th> |
| <th style='width:240px;'>Description</th> |
| <th style='width:240px;'>Documentation Link</th> |
| <th style='width:240px;'>Style Guide Usage</th> |
| </tr> |
| |
| <tr> |
| <td>Address Retrieval</td> |
| <td><code>std::addressof()</code></td> |
| <td>Obtains the address of an object even with overloaded <code>operator&</code></td> |
| <td><a href="http://en.cppreference.com/w/cpp/memory/addressof">std::addressof</a></td> |
| <td>Usage should be rare as |
| <a href="https://google-styleguide.googlecode.com/svn/trunk/cppguide.html#Operator_Overloading"> |
| Operator Overloading</a> is rare and <code>&s;</code> |
| should suffice in most cases. May be preferable |
| over <code>&s;</code> for performing object |
| identity checks.</td> |
| </tr> |
| |
| <tr> |
| <td>Aligned Storage</td> |
| <td><code>std::aligned_storage<Size, Align>::type</code></td> |
| <td>Declare uninitialized storage having a specified alignment.</td> |
| <td><a href="http://en.cppreference.com/w/cpp/types/aligned_storage">std::aligned_storage</a></td> |
| <td>Note: <code>std::aligned_storage</code> is allowed, but some other C++11 |
| alignment features are still disallowed.</td> |
| </tr> |
| |
| <tr> |
| <td>Allocator Traits</td> |
| <td><code>std::allocator_traits</code></td> |
| <td>Provides an interface for accessing custom allocators</td> |
| <td><a href="http://en.cppreference.com/w/cpp/memory/allocator_traits"> |
| std::allocator_traits</a></td> |
| <td>Usage should be rare.</td> |
| </tr> |
| |
| <tr> |
| <td>Atomics</td> |
| <td><code>std::atomic</code> and others in <code><atomic></code></td> |
| <td>Fine-grained atomic types and operations</td> |
| <td><a href="http://en.cppreference.com/w/cpp/atomic"><atomic></a></td> |
| <td></td> |
| </tr> |
| |
| <tr> |
| <td>Arrays</td> |
| <td><code>std::array</code></td> |
| <td>A fixed-size replacement for built-in arrays, with STL support</td> |
| <td><a href="http://en.cppreference.com/w/cpp/container/array"> |
| std::array</a></td> |
| <td></td> |
| </tr> |
| |
| <tr> |
| <td>Begin and End Non-Member Functions</td> |
| <td><code>std::begin()</code> and <code>std::end()</code></td> |
| <td>Allows use of free functions on any container, including |
| built-in arrays</td> |
| <td><a href="http://en.cppreference.com/w/cpp/iterator/begin"> |
| std::begin</a> and |
| <a href="http://en.cppreference.com/w/cpp/iterator/end"> |
| std::end</a></td> |
| <td>Useful for built-in arrays.</td> |
| </tr> |
| |
| <tr> |
| <td>Bind Operations</td> |
| <td><code>std::bind(<i>function</i>, <i>args</i>, ...)</code></td> |
| <td>Declares a function object bound to certain arguments</td> |
| <td>TODO: documentation link</td> |
| <td></td> |
| </tr> |
| |
| <tr> |
| <td>C Floating-Point Environment</td> |
| <td><code><cfenv></code></td> |
| <td>Provides floating point status flags and control modes for C-compatible code</td> |
| <td><a href="http://en.cppreference.com/w/cpp/header/cfenv">Standard library header <cfenv></a></td> |
| <td>Compilers do not support use</td> |
| </tr> |
| |
| <tr> |
| <td>Chrono Library</td> |
| <td><code><chrono></code></td> |
| <td>Provides a standard date and time library</td> |
| <td><a href="http://en.cppreference.com/w/cpp/chrono">Date and time utilities</a></td> |
| <td></td> |
| </tr> |
| |
| <tr> |
| <td>Complex Inverse Trigonometric and Hyperbolic Functions</td> |
| <td>Functions within <code><complex></code></td> |
| <td>Adds inverse trigonomentric and hyperbolic non-member functions to |
| the <code><complex></code> library.</td> |
| <td><a href="http://en.cppreference.com/w/cpp/numeric/complex">std::complex</a></td> |
| <td></td> |
| </tr> |
| |
| <tr> |
| <td>Conditional Type Selection</td> |
| <td><code>std::enable_if</code> and <code>std::conditional</code></td> |
| <td>Enables compile-time conditional type selection</td> |
| <td><a href="http://en.cppreference.com/w/cpp/types/enable_if"> |
| std::enable_if</a> and |
| <a href="http://en.cppreference.com/w/cpp/types/conditional"> |
| conditional</a></td> |
| <td></td> |
| </tr> |
| |
| <tr> |
| <td>Constant Iterator Methods on Containers</td> |
| <td><code>std::cbegin()</code> and <code>std::cend()</code></td> |
| <td>Enforces iteration methods that don't change container contents</td> |
| <td>TODO: documentation link</td> |
| <td></td> |
| </tr> |
| |
| <tr> |
| <td>Construct Elements in Containers</td> |
| <td><code>emplace()</code>,<code>emplace_back()</code>, |
| <code>emplace_front()</code>, <code>emplace_hint()</code></td> |
| <td>Constructs elements directly within a container without a copy |
| or a move</td> |
| <td>TODO: documentation link</td> |
| <td>Use where element construction within a container |
| is needed.</td> |
| </tr> |
| |
| <tr> |
| <td>Container Compaction Functions</td> |
| <td><code>std::vector::shrink_to_fit()</code>, |
| <code>std::deque::shrink_to_fit()</code>, and |
| <code>std::string::shrink_to_fit()</code></td> |
| <td>Requests the removal of unused space |
| in the container</td> |
| <td><a href="http://en.cppreference.com/w/cpp/container/vector/shrink_to_fit"> |
| std::vector::shrink_to_fit</a>, |
| <a href="http://en.cppreference.com/w/cpp/container/deque/shrink_to_fit"> |
| std::deque::shrink_to_fit</a>, and |
| <a href="http://en.cppreference.com/w/cpp/string/basic_string/shrink_to_fit"> |
| std::basic_string::shrink_to_fit</a></td> |
| <td></td> |
| </tr> |
| |
| <tr> |
| <td>Date/Time String Formatting Specifiers</td> |
| <td><code>std::strftime()</code></td> |
| <td>Converts date and time information into a |
| formatted string using new specifiers</td> |
| <td><a href="http://en.cppreference.com/w/cpp/chrono/c/strftime"> |
| std::strftime</a></td> |
| <td></td> |
| </tr> |
| |
| <tr> |
| <td>Function Return Type Deduction</td> |
| <td><code>std::result_of<<i>Functor(ArgTypes...)</i>></code></td> |
| <td>Extracts the return type from the type signature of |
| a function call invocation at compile-time.</td> |
| <td><a href="http://en.cppreference.com/w/cpp/types/result_of"> |
| std::result_of</a></td> |
| <td> |
| <a href="http://stackoverflow.com/questions/15486951/why-does-stdresult-of-take-an-unrelated-function-type-as-a-type-argument"> |
| Why does std::result_of take an (unrelated) function type as a type argument? |
| </a></td> |
| </tr> |
| |
| <tr> |
| <td>Function Objects</td> |
| <td><code>std::function</code></td> |
| <td>Wraps a standard polymorphic function</td> |
| <td>TODO: documentation link</td> |
| <td></td> |
| </tr> |
| |
| <tr> |
| <td>Forward Lists</td> |
| <td><code>std::forward_list</code></td> |
| <td>Provides an efficient singly linked list</td> |
| <td><a href="http://en.cppreference.com/w/cpp/container/forward_list"> |
| std::forward_list</a></td> |
| <td></td> |
| </tr> |
| |
| <tr> |
| <td>Gamma Natural Log</td> |
| <td><code>std::lgamma()</code></td> |
| <td>Computes the natural log of the gamma of a |
| floating point value</td> |
| <td><a href="http://en.cppreference.com/w/cpp/numeric/math/lgamma"> |
| std::lgamma</a></td> |
| <td></td> |
| </tr> |
| |
| <tr> |
| <td>Garbage Collection Features</td> |
| <td><code>std::{un}declare_reachable()</code> and |
| <code>std::{un}declare_no_pointers()</code></td> |
| <td>Enables garbage collection implementations</td> |
| <td><a href="http://en.cppreference.com/w/cpp/memory/gc/declare_reachable"> |
| std::declare_reachable</a> |
| and <a href="http://en.cppreference.com/w/cpp/memory/gc/declare_no_pointers"> |
| std::declare_no_pointers</a></td> |
| <td></td> |
| </tr> |
| |
| <tr> |
| <td>Heap Validation</td> |
| <td><code>std::is_heap()</code></td> |
| <td>Checks whether an iterator range is in fact a heap</td> |
| <td>TODO: documentation link</td> |
| <td></td> |
| </tr> |
| |
| <tr> |
| <td>Is Nan</td> |
| <td><code>std::isnan()</code></td> |
| <td>Determines if a floating point value is not-a-number</td> |
| <td><a href="http://en.cppreference.com/w/cpp/numeric/math/isnan">std::isnan</a></td> |
| <td></td> |
| </tr> |
| |
| <tr> |
| <td>Iterator Operators</td> |
| <td><code>std::next()</code> and <code>std::prev()</code></td> |
| <td>Copies an iterator and increments or decrements the copy by |
| some value</td> |
| <td><a href="http://en.cppreference.com/w/cpp/iterator/next">std::next</a> |
| and <a href="http://en.cppreference.com/w/cpp/iterator/prev">std::prev</a> |
| </td> |
| <td></td> |
| </tr> |
| |
| <tr> |
| <td>Initializer Lists</td> |
| <td><code>std::initializer_list<T></code></td> |
| <td>Allows containers to be initialized with aggregate elements</td> |
| <td>TODO: documentation link</td> |
| <td></td> |
| </tr> |
| |
| <tr> |
| <td>Move Semantics</td> |
| <td><code>std::move()</code></td> |
| <td>Facilitates efficient move operations</td> |
| <td><a href="http://en.cppreference.com/w/cpp/utility/move"> |
| <code>std::move</code> reference</a></td> |
| <td></td> |
| </tr> |
| |
| <tr> |
| <td>Pointer Traits Class Template</td> |
| <td><code>std::pointer_traits</code></td> |
| <td>Provides a standard way to access properties |
| of pointers and pointer-like types</td> |
| <td><a href="http://en.cppreference.com/w/cpp/memory/pointer_traits"> |
| std::pointer_traits</a></td> |
| <td>Useful for determining the element type |
| pointed at by a (possibly smart) pointer.</td> |
| </tr> |
| |
| <tr> |
| <td>Random Number Generators</td> |
| <td>Functions within <code><random></code></td> |
| <td>Random number generation algorithms and utilities</td> |
| <td><a href="http://en.cppreference.com/w/cpp/numeric/random"> |
| Pseudo-random number generation</a></td> |
| <td></td> |
| </tr> |
| |
| <tr> |
| <td>Ratio Template Class</td> |
| <td><code>std::ratio<<i>numerator</i>, <i>denominator</i>></code></td> |
| <td>Provides compile-time rational numbers</td> |
| <td>TODO: documentation link</td> |
| <td></td> |
| </tr> |
| |
| <tr> |
| <td>Reference Wrapper Classes</td> |
| <td><code>std::reference_wrapper</code> and |
| <code>std::ref()</code>, <code>std::cref()</code></td> |
| <td>Allows you to wrap a reference within a standard |
| object (and use those within containers)</td> |
| <td><a href="http://www.informit.com/guides/content.aspx?g=cplusplus&seqNum=217"> |
| Reference Wrappers</a></td> |
| <td></td> |
| </tr> |
| |
| <tr> |
| <td>Regex Library</td> |
| <td><code><regex></code></td> |
| <td>Provides a standard regular expressions library</td> |
| <td><a href="http://en.cppreference.com/w/cpp/regex">Regular expressions library</a></td> |
| <td></td> |
| </tr> |
| |
| <tr> |
| <td>Shared Pointers</td> |
| <td><code>std::shared_ptr</code></td> |
| <td>Allows shared ownership of a pointer through reference counts</td> |
| <td><a href="http://en.cppreference.com/w/cpp/memory/shared_ptr">std::shared_ptr</a></td> |
| <td><a href="https://google-styleguide.googlecode.com/svn/trunk/cppguide.html#Ownership_and_Smart_Pointers"> |
| Ownership and Smart Pointers</a></td> |
| </tr> |
| |
| <tr> |
| <td>Soft Program Exits</td> |
| <td><code>std::at_quick_exit()</code> |
| and <code>std::quick_exit()</code></td> |
| <td>Allows registration of functions to be called upon exit, |
| allowing cleaner program exit than <code>abort()</code> or |
| <code>exit</code></td> |
| <td><a href="http://en.cppreference.com/w/cpp/utility/program/quick_exit"> |
| std:quick_exit</a></td> |
| <td></td> |
| </tr> |
| |
| <tr> |
| <td>String Direct Reference Functions</td> |
| <td><code>std::string::front()</code> and <code>std::string::back()</code></td> |
| <td>Returns a reference to the front or back of a string</td> |
| <td><a href="http://en.cppreference.com/w/cpp/string/basic_string/front"> |
| std::basic_string::front</a> and |
| <a href="http://en.cppreference.com/w/cpp/string/basic_string/back"> |
| std::basic_string::back</a></td> |
| <td></td> |
| </tr> |
| |
| <tr> |
| <td>String to Number Functions</td> |
| <td><code>std::stoi()</code>, <code>std::stol()</code>, |
| <code>std::stoul()</code>, <code>std::stoll</code>, <code>std::stoull()</code>, |
| <code>std::stof()</code>, <code>std::stod()</code>, <code>std::stold()</code>, |
| and <code>std::to_string()</code></td> |
| <td>Converts strings to numbers</td> |
| <td><a href="http://en.cppreference.com/w/cpp/string/basic_string/stol"> |
| std::stoi, std::stol, std::stoll</a>, |
| <a href="http://en.cppreference.com/w/cpp/string/basic_string/stoul"> |
| std::stoul, std::stoull</a>, and |
| <a href="http://en.cppreference.com/w/cpp/string/basic_string/stof"> |
| std::stof, std::stod, std::stold</a> </td> |
| <td></td> |
| </tr> |
| |
| <tr> |
| <td>STL Algorithms</td> |
| <td>Functions within <code><algorithm></code>.</td> |
| <td>Enhancements to the set of STL algorithms</td> |
| <td>See the <a href="http://en.cppreference.com/w/cpp/algorithm"> |
| Algorithms library</a> for a complete list.</td> |
| <td></td> |
| </tr> |
| |
| <tr> |
| <td>System Errors</td> |
| <td><code><system_error></code></td> |
| <td>Provides a standard system error library</td> |
| <td><a href="http://en.cppreference.com/w/cpp/error/system_error">std::system_error</a></td> |
| <td></td> |
| </tr> |
| |
| <tr> |
| <td>Trailing Return Types</td> |
| <td><code>auto <i>function declaration</i> -> <i>return_type</i></code></td> |
| <td>Allows trailing function return value syntax</td> |
| <td><a href="http://en.cppreference.com/w/cpp/language/function"> |
| Declaring functions</a></td> |
| <td><a href="https://groups.google.com/a/chromium.org/forum/#!topic/chromium-dev/OQyYSfH9m2M">Discussion thread</a></td> |
| </tr> |
| |
| <tr> |
| <td>Thread Library</td> |
| <td><code><thread> support, including <future>, |
| <mutex>, <condition_variable></code></td> |
| <td>Provides a standard mulitthreading library using <code>std::thread</code> and associates</td> |
| <td><a href="http://en.cppreference.com/w/cpp/thread">Thread support library</a></td> |
| <td></td> |
| </tr> |
| |
| <tr> |
| <td>Tuples</td> |
| <td><code>std::tuple</code></td> |
| <td>A fixed-size ordered collection of values of mixed types</td> |
| <td>TODO: documentation link</td> |
| <td></td> |
| </tr> |
| |
| <tr> |
| <td>Type-Generic Math Functions</td> |
| <td>Functions within <code><ctgmath></code></td> |
| <td>Provides a means to call real or complex functions |
| based on the type of arguments</td> |
| <td><a href="http://en.cppreference.com/w/cpp/header/ctgmath"> |
| Standard library header <ctgmath></a></td> |
| <td></td> |
| </tr> |
| |
| <tr> |
| <td>Type Info Enhancements</td> |
| <td><code>std::type_index</code> and <code>std::type_info::hash_code()</code></td> |
| <td>Allows type information (most often within containers) |
| that can be copied, assigned, or hashed</td> |
| <td><a href="http://en.cppreference.com/w/cpp/types/type_index"> |
| std::type_index</a> and |
| <a href="http://en.cppreference.com/w/cpp/types/type_info/hash_code"> |
| std::type_info::hash_code</a></td> |
| <td><code>std::type_index</code> is a thin wrapper for |
| <code>std::type_info</code>, allowing you to use it directly |
| within both associative and unordered containers</td> |
| </tr> |
| |
| <tr> |
| <td>Type Traits</td> |
| <td>Class templates within <code><type_traits></code></td> |
| <td>Allows compile-time inspection of the properties of types</td> |
| <td><a href="http://en.cppreference.com/w/cpp/header/type_traits"> |
| Standard library header <type_traits></a></td> |
| <td></td> |
| </tr> |
| |
| <tr> |
| <td>Unique Pointers</td> |
| <td><code>std::unique_ptr<<i>type</i>></code></td> |
| <td>Defines a pointer with clear and unambiguous ownership</td> |
| <td>TODO: documentation link</td> |
| <td><a href="https://google-styleguide.googlecode.com/svn/trunk/cppguide.html#Ownership_and_Smart_Pointers"> |
| Ownership and Smart Pointers</a></td> |
| </tr> |
| |
| <tr> |
| <td>Unordered Associative Containers</td> |
| <td><code>std::unordered_set</code>, <code>std::unordered_map</code>, |
| <code>std::unordered_multiset</code>, and <code>std::unordered_multimap</code></td> |
| <td>Allows efficient containers of key/value pairs</td> |
| <td><a href="http://en.cppreference.com/w/cpp/container/unordered_map">std::unordered_map</a> |
| and <a href="http://en.cppreference.com/w/cpp/container/unordered_set">std::unordered_set</a> |
| </td> |
| <td></td> |
| </tr> |
| |
| <tr> |
| <td>Variadic Copy Macro</td> |
| <td><code>va_copy(va_list <i>dest</i>, va_list <i>src</i>)</code></td> |
| <td>Makes a copy of the variadic function arguments</td> |
| <td></td> |
| <td></td> |
| </tr> |
| |
| <tr> |
| <td>Weak Pointers</td> |
| <td><code>std::weak_ptr</code></td> |
| <td>Allows a weak reference to a <code>std::shared_ptr</code></td> |
| <td><a href="http://en.cppreference.com/w/cpp/memory/weak_ptr"> |
| std::weak_ptr</a></td> |
| <td><a href="https://google-styleguide.googlecode.com/svn/trunk/cppguide.html#Ownership_and_Smart_Pointers"> |
| Ownership and Smart Pointers</a></td> |
| </tr> |
| |
| <tr> |
| <td>Wide String Support</td> |
| <td><code>std::wstring_convert</code>, |
| <code>std::wbuffer_convert</code>. |
| <code>std::codecvt_utf8</code>, <code>std::codecvt_utf16</code>, |
| and <code>std::codecvt_utf8_utf16</code></td> |
| <td>Converts between string encodings</td> |
| <td><a href="http://en.cppreference.com/w/cpp/locale/wstring_convert"> |
| std::wstring_convert</a>, |
| <a href="http://en.cppreference.com/w/cpp/locale/wbuffer_convert"> |
| std::wbuffer_convert</a>, |
| <a href="http://en.cppreference.com/w/cpp/locale/codecvt_utf8"> |
| std::codecvt_utf8</a>, |
| <a href="http://en.cppreference.com/w/cpp/locale/codecvt_utf16"> |
| std::codecvt_utf16</a>, and |
| <a href="http://en.cppreference.com/w/cpp/locale/codecvt_utf8_utf16"> |
| std::codecvt_utf8_utf16</a> |
| </td> |
| <td>Non-UTF-8 text is banned by the |
| <a href="https://google-styleguide.googlecode.com/svn/trunk/cppguide.html#Non-ASCII_Characters"> |
| C++ Style Guide</a>. However, may be useful for |
| consuming non-ASCII data.</td> |
| </tr> |
| |
| </tbody> |
| </table> |
| |
| </details> |
| |
| </div> |
| </body> |
| </html> |