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<h1>C++ Support in Clang</h1>
<p>Clang implements the following published and upcoming ISO C++ standards:</p>
<table width="689" border="1" cellspacing="0">
<tr>
<th>Language Standard</th>
<th>Flag</th>
<th>Available in Clang?</th>
</tr>
<tr>
<td><a href="#cxx98">C++98 / C++03</a></td>
<td><tt>-std=c++98</tt></td>
<td class="full" align="center">Yes (other than <tt>export</tt>)</td>
</tr>
<tr>
<td><a href="#cxx11">C++11</a></td>
<td><tt>-std=c++11</tt></td>
<td class="full" align="center">Clang 3.3</td>
</tr>
<tr>
<td><a href="#cxx14">C++14</a></td>
<td><tt>-std=c++14</tt></td>
<td class="full" align="center">Clang 3.4</td>
</tr>
<tr>
<td><a href="#cxx17">C++17</a></td>
<td><tt>-std=c++17</tt></td>
<td class="full" align="center">Clang 5</td>
</tr>
<tr>
<td><a href="#cxx20">C++20</a></td>
<td><tt>-std=c++20</tt></td>
<td class="partial" align="center">Partial</td>
</tr>
<tr>
<td><a href="#cxx23">C++2b (tentatively C++23)</a></td>
<td><tt>-std=c++2b</tt></td>
<td class="partial" align="center">Partial</td>
</tr>
</table>
<p>The Clang community is continually striving to improve C++ standards
compliance between releases by submitting and tracking <a
href="cxx_dr_status.html">C++ Defect Reports</a> and implementing resolutions
as they become available.</p>
<p>Experimental work is also under way to implement <a href="#ts">C++ Technical
Specifications</a> that will help drive the future of the C++ programming
language.</p>
<p>The <a href="https://github.com/llvm/llvm-project/issues/">LLVM bug tracker</a> uses
the "c++" label, as well as mode-specific labels such as "c++11", "c++14",
and so on, to track known bugs with Clang's language conformance.</p>
<h2 id="cxx98">C++98 implementation status</h2>
<p>Clang implements all of the ISO C++ 1998 standard
(including the defects addressed in the ISO C++ 2003 standard)
except for <tt>export</tt> (which was removed in C++11).
<h2 id="cxx11">C++11 implementation status</h2>
<p>Clang 3.3 and later implement all of the <a
href="https://www.iso.org/standard/50372.html">ISO
C++ 2011 standard</a>.</p>
<p>You can use Clang in C++11 mode with the <code>-std=c++11</code>
option. Clang's C++11 mode can be used with
<a href="https://libcxx.llvm.org/">libc++</a> or with gcc's libstdc++.</p>
<details>
<summary>List of features and minimum Clang version with support</summary>
<table width="689" border="1" cellspacing="0">
<tr>
<th>Language Feature</th>
<th>C++11 Proposal</th>
<th>Available in Clang?</th>
</tr>
<tr>
<td rowspan="2">Rvalue references</td>
<td><a href="https://wg21.link/n2118">N2118</a></td>
<td class="full" align="center">Clang 2.9</td>
<tr>
<td><a href="https://wg21.link/p1825r0">P1825R0</a> (<a href="#dr">DR</a>)</td>
<td class="full" align="center">Clang 13</td>
</tr>
</tr>
<tr>
<td> Rvalue references for <code>*this</code></td>
<td><a href="https://wg21.link/n2439">N2439</a></td>
<td class="full" align="center">Clang 2.9</td>
</tr>
<tr>
<td>Initialization of class objects by rvalues</td>
<td><a href="https://wg21.link/n1610">N1610</a></td>
<td class="full" align="center">Clang 2.9</td>
</tr>
<tr>
<td>Non-static data member initializers</td>
<td><a href="https://wg21.link/n2756">N2756</a></td>
<td class="full" align="center">Clang 3.0</td>
</tr>
<tr>
<td>Variadic templates</td>
<td><a href="https://wg21.link/n2242">N2242</a></td>
<td class="full" align="center">Clang 2.9</td>
</tr>
<tr>
<td> Extending variadic template template parameters</td>
<td><a href="https://wg21.link/n2555">N2555</a></td>
<td class="full" align="center">Clang 2.9</td>
</tr>
<tr>
<td rowspan="3">Initializer lists</td>
<td><a href="https://wg21.link/n2672">N2672</a></td>
<td class="full" align="center">Clang 3.1</td>
</tr>
<tr>
<td><a href="https://wg21.link/p1009r2">P1009R2</a> (<a href="#dr">DR</a>)</td>
<td class="full" align="center">Clang 9</td>
</tr>
<tr>
<td><a href="https://wg21.link/p1957r2">P1957R2</a> (<a href="#dr">DR</a>)</td>
<td class="full" align="center">Clang 11</td>
</tr>
<tr>
<td>Static assertions</td>
<td><a href="https://wg21.link/n1720">N1720</a></td>
<td class="full" align="center">Clang 2.9</td>
</tr>
<tr>
<td><code>auto</code>-typed variables</td>
<td><a href="https://wg21.link/n1984">N1984</a></td>
<td class="full" align="center">Clang 2.9</td>
</tr>
<tr>
<td> Multi-declarator <code>auto</code></td>
<td><a href="https://wg21.link/n1737">N1737</a></td>
<td class="full" align="center">Clang 2.9</td>
</tr>
<tr>
<td> Removal of auto as a storage-class specifier</td>
<td><a href="https://wg21.link/n2546">N2546</a></td>
<td class="full" align="center">Clang 2.9</td>
</tr>
<tr>
<td> New function declarator syntax</td>
<td><a href="https://wg21.link/n2541">N2541</a></td>
<td class="full" align="center">Clang 2.9</td>
</tr>
<tr>
<td rowspan="2">Lambda expressions</td>
<td><a href="https://wg21.link/n2927">N2927</a></td>
<td class="full" align="center">Clang 3.1</td>
</tr>
<tr>
<td><a href="https://wg21.link/p0588r1">P0588R1</a> (<a href="#dr">DR</a>)</td>
<td class="none" align="center">No</td>
</tr>
<tr>
<td>Declared type of an expression</td>
<td><a href="https://wg21.link/n2343">N2343</a></td>
<td class="full" align="center">Clang 2.9</td>
</tr>
<tr>
<td> Incomplete return types</td>
<td><a href="https://wg21.link/n3276">N3276</a></td>
<td class="full" align="center">Clang 3.1</td>
</tr>
<tr>
<td>Right angle brackets</td>
<td><a href="https://wg21.link/n1757">N1757</a></td>
<td class="full" align="center">Clang 2.9</td>
</tr>
<tr>
<td>Default template arguments for function templates</td>
<td><a href="https://wg21.link/cwg226">DR226</a></td>
<td class="full" align="center">Clang 2.9</td>
</tr>
<tr>
<td>Solving the SFINAE problem for expressions</td>
<td><a href="https://wg21.link/n2634">DR339</a></td>
<td class="full" align="center">Clang 2.9</td>
</tr>
<tr>
<td>Alias templates</td>
<td><a href="https://wg21.link/n2258">N2258</a></td>
<td class="full" align="center">Clang 3.0</td>
</tr>
<tr>
<td>Extern templates</td>
<td><a href="https://wg21.link/n1987">N1987</a></td>
<td class="full" align="center">Clang 2.9</td>
</tr>
<tr>
<td>Null pointer constant</td>
<td><a href="https://wg21.link/n2431">N2431</a></td>
<td class="full" align="center">Clang 3.0</td>
</tr>
<tr>
<td>Strongly-typed enums</td>
<td><a href="https://wg21.link/n2347">N2347</a></td>
<td class="full" align="center">Clang 2.9</td>
</tr>
<tr>
<td>Forward declarations for enums</td>
<td><a href="https://wg21.link/n2764">N2764</a>
<br><a href="https://wg21.link/cwg1206">DR1206</a></td>
<td class="full" align="center">Clang 3.1</td>
</tr>
<tr>
<td>Standardized attribute syntax</td>
<td><a href="https://wg21.link/n2761">N2761</a></td>
<td class="full" align="center">Clang 3.3 <a href="#n2761">(1)</a></td>
</tr>
<tr>
<td rowspan="2">Generalized constant expressions</td>
<td><a href="https://wg21.link/n2235">N2235</a></td>
<td class="full" align="center">Clang 3.1</td>
</tr>
<tr>
<td><a href="https://wg21.link/p0859r0">P0859R0</a> (<a href="#dr">DR</a>)</td>
<td class="full" align="center">Clang 8</td>
</tr>
<tr>
<td>Alignment support</td>
<td><a href="https://wg21.link/n2341">N2341</a></td>
<td class="full" align="center">Clang 3.3</td>
</tr>
<tr>
<td>Conditionally-support behavior</td>
<td><a href="https://wg21.link/n1627">N1627</a></td>
<td class="full" align="center">Clang 2.9</td>
</tr>
<tr>
<td>Changing undefined behavior into diagnosable errors</td>
<td><a href="https://wg21.link/n1727">N1727</a></td>
<td class="full" align="center">Clang 2.9</td>
</tr>
<tr>
<td>Delegating constructors</td>
<td><a href="https://wg21.link/n1986">N1986</a></td>
<td class="full" align="center">Clang 3.0</td>
</tr>
<tr>
<td rowspan="2">Inheriting constructors</td>
<td><a href="https://wg21.link/n2540">N2540</a></td>
<td class="full" align="center">Clang 3.3</td>
</tr>
<tr>
<td><a href="https://wg21.link/p0136r1">P0136R1</a> (<a href="#dr">DR</a>)</td>
<td class="full" align="center">Clang 3.9</td>
</tr>
<tr>
<td>Explicit conversion operators</td>
<td><a href="https://wg21.link/n2437">N2437</a></td>
<td class="full" align="center">Clang 3.0</td>
</tr>
<tr>
<td>New character types</td>
<td><a href="https://wg21.link/n2249">N2249</a></td>
<td class="full" align="center">Clang 2.9</td>
</tr>
<tr>
<td>Unicode string literals</td>
<td><a href="https://wg21.link/n2442">N2442</a></td>
<td class="full" align="center">Clang 3.0</td>
</tr>
<tr>
<td>Raw string literals</td>
<td><a href="https://wg21.link/n2442">N2442</a></td>
<td class="full" align="center">Clang 3.0</td>
</tr>
<tr>
<td>Universal character names in literals</td>
<td><a href="https://wg21.link/n2170">N2170</a></td>
<td class="full" align="center">Clang 3.1</td>
</tr>
<tr>
<td>User-defined literals</td>
<td><a href="https://wg21.link/n2765">N2765</a></td>
<td class="full" align="center">Clang 3.1</td>
</tr>
<tr>
<td>Standard Layout Types</td>
<td><a href="https://wg21.link/n2342">N2342</a></td>
<td class="full" align="center">Clang 3.0</td>
</tr>
<tr>
<td rowspan="2">Defaulted functions</td>
<td><a href="https://wg21.link/n2346">N2346</a></td>
<td class="full" align="center">Clang 3.0</td>
</tr>
<tr>
<td><a href="https://wg21.link/p1286r2">P1286R2</a> (<a href="#dr">DR</a>)</td>
<td class="full" align="center">Clang 9</td>
</tr>
<tr>
<td>Deleted functions</td>
<td><a href="https://wg21.link/n2346">N2346</a></td>
<td class="full" align="center">Clang 2.9</td>
</tr>
<tr>
<td>Extended friend declarations</td>
<td><a href="https://wg21.link/n1791">N1791</a></td>
<td class="full" align="center">Clang 2.9</td>
</tr>
<tr>
<td>Extending <code>sizeof</code></td>
<td><a href="https://wg21.link/n2253">N2253</a>
<br><a href="https://wg21.link/cwg850">DR850</a></td>
<td class="full" align="center">Clang 3.1</td>
</tr>
<tr>
<td>Inline namespaces</td>
<td><a href="https://wg21.link/n2535">N2535</a></td>
<td class="full" align="center">Clang 2.9</td>
</tr>
<tr>
<td>Unrestricted unions</td>
<td><a href="https://wg21.link/n2544">N2544</a></td>
<td class="full" align="center">Clang 3.1</td>
</tr>
<tr>
<td>Local and unnamed types as template arguments</td>
<td><a href="https://wg21.link/n2657">N2657</a></td>
<td class="full" align="center">Clang 2.9</td>
</tr>
<tr>
<td rowspan="2">Range-based for</td>
<td><a href="https://wg21.link/n2930">N2930</a></td>
<td class="full" align="center">Clang 3.0</td>
</tr>
<tr>
<td><a href="https://wg21.link/p0962r1">P0962R1</a> (<a href="#dr">DR</a>)</td>
<td class="full" align="center">Clang 8</td>
</tr>
<tr>
<td>Explicit virtual overrides</td>
<td><a href="https://wg21.link/n2928">N2928</a>
<br><a href="https://wg21.link/n3206">N3206</a>
<br><a href="https://wg21.link/n3272">N3272</a></td>
<td class="full" align="center">Clang 3.0</td>
</tr>
<tr>
<td>Minimal support for garbage collection and reachability-based leak detection</td>
<td><a href="https://wg21.link/n2670">N2670</a></td>
<td class="na" align="center">N/A <a href="#n2670">(2)</a></td>
</tr>
<tr>
<td>Allowing move constructors to throw [noexcept]</td>
<td><a href="https://wg21.link/n3050">N3050</a></td>
<td class="full" align="center">Clang 3.0</td>
</tr>
<tr>
<td>Defining move special member functions</td>
<td><a href="https://wg21.link/n3053">N3053</a></td>
<td class="full" align="center">Clang 3.0</td>
</tr>
<tr class="separator">
<th align="center" colspan="3">Concurrency</th>
</tr>
<tr>
<td>Sequence points</td>
<td><a href="https://wg21.link/n2239">N2239</a></td>
<td class="full" align="center">Clang 3.3</td>
</tr>
<tr>
<td>Atomic operations</td>
<td><a href="https://wg21.link/n2427">N2427</a></td>
<td class="full" align="center">Clang 3.1</td>
</tr>
<tr>
<td>Strong Compare and Exchange</td>
<td><a href="https://wg21.link/n2748">N2748</a></td>
<td class="full" align="center">Clang 3.1 <a href="#n2748">(3)</a></td>
</tr>
<tr>
<td>Bidirectional Fences</td>
<td><a href="https://wg21.link/n2752">N2752</a></td>
<td class="full" align="center">Clang 3.1</td>
</tr>
<tr>
<td>Memory model</td>
<td><a href="https://wg21.link/n2429">N2429</a></td>
<td class="full" align="center">Clang 3.2</td>
</tr>
<tr>
<td>Data-dependency ordering: atomics and memory model</td>
<td><a href="https://wg21.link/n2664">N2664</a></td>
<td class="full" align="center">Clang 3.2 <a href="#n2664">(4)</a></td>
</tr>
<tr>
<td>Propagating exceptions</td>
<td><a href="https://wg21.link/n2179">N2179</a></td>
<td class="full" align="center">Clang 2.9</td>
</tr>
<tr>
<td>Allow atomics use in signal handlers</td>
<td><a href="https://wg21.link/n2547">N2547</a></td>
<td class="full" align="center">Clang 3.1</td>
</tr>
<tr>
<td>Thread-local storage</td>
<td><a href="https://wg21.link/n2659">N2659</a></td>
<td class="full" align="center">Clang 3.3 <a href="#n2659">(5)</a></td>
</tr>
<tr>
<td>Dynamic initialization and destruction with concurrency</td>
<td><a href="https://wg21.link/n2660">N2660</a></td>
<td class="full" align="center">Clang 2.9</td>
</tr>
<tr class="separator">
<th align="center" colspan="3">C99 Features in C++11</th>
</tr>
<tr>
<td><code>__func__</code> predefined identifier</td>
<td><a href="https://wg21.link/n2340">N2340</a></td>
<td class="full" align="center">Clang 2.9</td>
</tr>
<tr>
<td>C99 preprocessor</td>
<td><a href="https://wg21.link/n1653">N1653</a></td>
<td class="full" align="center">Clang 2.9</td>
</tr>
<tr>
<td><code>long long</code></td>
<td><a href="https://wg21.link/n1811">N1811</a></td>
<td class="full" align="center">Clang 2.9</td>
</tr>
<tr>
<td>Extended integral types</td>
<td><a href="https://wg21.link/n1988">N1988</a></td>
<td class="na" align="center">N/A <a href="#n1988">(6)</a></td>
</tr>
</table>
<p>
<span id="n2761">(1): The <code>[[carries_dependency]]</code> attribute
has no effect.</span><br>
<span id="n2670">(2): No compiler changes are required for an implementation
such as Clang that does not provide garbage collection.</span><br>
<span id="n2748">(3): All compare-exchange operations are emitted as
strong compare-exchanges.</span><br>
<span id="n2664">(4): <code>memory_order_consume</code> is lowered to
<code>memory_order_acquire</code>.</span><br>
<span id="n2659">(5): <code>thread_local</code> support
requires a C++ runtime library providing <code>__cxa_thread_atexit</code>, such
as <a href="https://libcxxabi.llvm.org">libc++abi</a> 3.6 or later,
or libsupc++ 4.8 or later.</span><br>
<span id="n1988">(6): No compiler changes are required for an implementation
such as Clang that does not provide any extended integer types.
<code>__int128</code> is not treated as an extended integer type,
because changing <code>intmax_t</code> would be an ABI-incompatible
change.</span>
</p>
</details>
<h2 id="cxx14">C++14 implementation status</h2>
<p>Clang 3.4 and later implement all of the <a
href="https://www.iso.org/standard/64029.html">ISO
C++ 2014 standard</a>.</p>
<p>By default, Clang builds C++ code according to the C++14 standard.
You can use Clang in C++14 mode with the <code>-std=c++14</code> option
(use <code>-std=c++1y</code> in Clang 3.4 and earlier).</p>
<details>
<summary>List of features and minimum Clang version with support</summary>
<table width="689" border="1" cellspacing="0">
<tr>
<th>Language Feature</th>
<th>C++14 Proposal</th>
<th>Available in Clang?</th>
</tr>
<tr>
<td>Tweak to certain C++ contextual conversions</td>
<td><a href="https://wg21.link/n3323">N3323</a></td>
<td class="full" align="center">Clang 3.4</td>
</tr>
<tr>
<td>Binary literals</td>
<td><a href="https://wg21.link/n3472">N3472</a></td>
<td class="full" align="center">Clang 2.9</td>
</tr>
<tr>
<td>decltype(auto)</td>
<td rowspan=2 style="vertical-align:middle"><a href="https://wg21.link/n3638">N3638</a></td>
<td class="full" align="center">Clang 3.3</td>
</tr>
<tr>
<td>Return type deduction for normal functions</td>
<td class="full" align="center">Clang 3.4</td>
</tr>
<tr>
<td>Initialized lambda captures</td>
<td><a href="https://wg21.link/n3648">N3648</a></td>
<td class="full" align="center">Clang 3.4</td>
</tr>
<tr>
<td>Generic lambdas</td>
<td><a href="https://wg21.link/n3649">N3649</a></td>
<td class="full" align="center">Clang 3.4</td>
</tr>
<tr>
<td>Variable templates</td>
<td><a href="https://wg21.link/n3651">N3651</a></td>
<td class="full" align="center">Clang 3.4</td>
</tr>
<tr>
<td>Relaxing requirements on constexpr functions</td>
<td><a href="https://wg21.link/n3652">N3652</a></td>
<td class="full" align="center">Clang 3.4</td>
</tr>
<tr>
<td>Member initializers and aggregates</td>
<td><a href="https://wg21.link/n3653">N3653</a></td>
<td class="full" align="center">Clang 3.3</td>
</tr>
<tr>
<td>Clarifying memory allocation</td>
<td><a href="https://wg21.link/n3664">N3664</a></td>
<td class="full" align="center">Clang 3.4</td>
</tr>
<tr>
<td><tt>[[deprecated]]</tt> attribute</td>
<td><a href="https://wg21.link/n3760">N3760</a></td>
<td class="full" align="center">Clang 3.4</td>
</tr>
<tr>
<td>Single quotation mark as digit separator</td>
<td><a href="https://wg21.link/n3781">N3781</a></td>
<td class="full" align="center">Clang 3.4</td>
</tr>
<tr>
<td>C++ Sized Deallocation</td>
<td><a href="https://wg21.link/n3778">N3778</a></td>
<td class="full" align="center">Clang 3.4 <a href="#n3778">(7)</a></td>
</tr>
</table>
<p>
<span id="n3778">(7): In Clang 3.7 and later, sized deallocation is only enabled
if the user passes the <code>-fsized-deallocation</code> flag. The user must
supply definitions of the sized deallocation functions, either by providing them
explicitly or by using a C++ standard library that does. <code>libstdc++</code>
added these functions in version 5.0, and <code>libc++</code> added them in
version 3.7.
</span>
</p>
</details>
<h2 id="cxx17">C++17 implementation status</h2>
<p>Clang 5 and later implement all the features of the
<a href="https://www.iso.org/standard/68564.html">ISO C++ 2017 standard</a>.</p>
<p>You can use Clang in C++17 mode with the <code>-std=c++17</code> option
(use <code>-std=c++1z</code> in Clang 4 and earlier).</p>
<details open>
<summary>List of features and minimum Clang version with support</summary>
<table width="689" border="1" cellspacing="0">
<tr>
<th>Language Feature</th>
<th>C++17 Proposal</th>
<th>Available in Clang?</th>
</tr>
<tr>
<td><tt>static_assert</tt> with no message</td>
<td><a href="https://wg21.link/n3928">N3928</a></td>
<td class="full" align="center">Clang 3.5</td>
</tr>
<tr>
<td>Disabling trigraph expansion by default</td>
<td><a href="https://wg21.link/n4086">N4086</a></td>
<td class="full" align="center">Clang 3.5</td>
</tr>
<tr>
<td><tt>typename</tt> in a template template parameter</td>
<td><a href="https://wg21.link/n4051">N4051</a></td>
<td class="full" align="center">Clang 3.5</td>
</tr>
<tr>
<td>New <tt>auto</tt> rules for direct-list-initialization
<td><a href="https://wg21.link/n3922">N3922</a></td>
<td class="full" align="center">Clang 3.8 <a href="#n3922">(8)</a></td>
</tr>
<tr>
<td rowspan="2">Fold expressions</td>
<td><a href="https://wg21.link/n4295">N4295</a></td>
<td class="full" align="center">Clang 3.6</td>
</tr>
<tr>
<td><a href="https://wg21.link/p0036r0">P0036R0</a></td>
<td class="full" align="center">Clang 3.9</td>
</tr>
<tr>
<td><tt>u8</tt> character literals</td>
<td><a href="https://wg21.link/n4267">N4267</a></td>
<td class="full" align="center">Clang 3.6</td>
</tr>
<tr>
<td>Nested namespace definition</td>
<td><a href="https://wg21.link/n4230">N4230</a></td>
<td class="full" align="center">Clang 3.6</td>
</tr>
<tr>
<td>Attributes for namespaces and enumerators</td>
<td><a href="https://wg21.link/n4266">N4266</a></td>
<td class="full" align="center">Clang 3.6</td>
</tr>
<tr>
<td>Allow constant evaluation for all non-type template arguments</td>
<td><a href="https://wg21.link/n4268">N4268</a></td>
<td class="full" align="center">Clang 3.6</td>
</tr>
<tr>
<td>Remove deprecated <tt>register</tt> storage class</td>
<td><a href="https://wg21.link/p0001r1">P0001R1</a></td>
<td class="full" align="center">Clang 3.8</td>
</tr>
<tr>
<td>Remove deprecated <tt>bool</tt> increment</td>
<td><a href="https://wg21.link/p0002r1">P0002R1</a></td>
<td class="full" align="center">Clang 3.8</td>
</tr>
<tr>
<td>Make exception specifications part of the type system</td>
<td><a href="https://wg21.link/p0012r1">P0012R1</a></td>
<td class="full" align="center">Clang 4</td>
</tr>
<tr>
<td><tt>__has_include</tt> in preprocessor conditionals</td>
<td><a href="https://wg21.link/p0061r1">P0061R1</a></td>
<td class="full" align="center">Yes</td>
</tr>
<tr>
<td><tt>[[fallthrough]]</tt> attribute</td>
<td><a href="https://wg21.link/p0188r1">P0188R1</a></td>
<td class="full" align="center">Clang 3.9</td>
</tr>
<tr>
<td rowspan="2"><tt>[[nodiscard]]</tt> attribute</td>
<td><a href="https://wg21.link/p0189r1">P0189R1</a></td>
<td class="full" align="center">Clang 3.9</td>
</tr>
<tr>
<td><a href="https://wg21.link/p1771r1">P1771R1</a> (<a href="#dr">DR</a>)</td>
<td class="full" align="center">Clang 9</td>
</tr>
<tr>
<td><tt>[[maybe_unused]]</tt> attribute</td>
<td><a href="https://wg21.link/p0212r1">P0212R1</a></td>
<td class="full" align="center">Clang 3.9</td>
</tr>
<tr>
<td>Aggregate initialization of classes with base classes</td>
<td><a href="https://wg21.link/p0017r1">P0017R1</a></td>
<td class="full" align="center">Clang 3.9</td>
</tr>
<tr>
<td><tt>constexpr</tt> lambda expressions</td>
<td><a href="https://wg21.link/p0170r1">P0170R1</a></td>
<td class="full" align="center">Clang 5</td>
</tr>
<tr>
<td>Differing <tt>begin</tt> and <tt>end</tt> types in range-based <tt>for</tt></td>
<td><a href="https://wg21.link/p0184r0">P0184R0</a></td>
<td class="full" align="center">Clang 3.9</td>
</tr>
<tr>
<td>Lambda capture of <tt>*this</tt></td>
<td><a href="https://wg21.link/p0018r3">P0018R3</a></td>
<td class="full" align="center">Clang 3.9</td>
</tr>
<tr>
<td>Direct-list-initialization of <tt>enum</tt>s</td>
<td><a href="https://wg21.link/p0138r2">P0138R2</a></td>
<td class="full" align="center">Clang 3.9</td>
</tr>
<tr>
<td>Hexadecimal floating-point literals</td>
<td><a href="https://wg21.link/p0245r1">P0245R1</a></td>
<td class="full" align="center">Yes</td>
</tr>
<tr>
<td>Using attribute namespaces without repetition</td>
<td><a href="https://wg21.link/p0028r4">P0028R4</a></td>
<td class="full" align="center">Clang 3.9</td>
</tr>
<tr>
<td>Dynamic memory allocation for over-aligned data</td>
<td><a href="https://wg21.link/p0035r4">P0035R4</a></td>
<td class="full" align="center">Clang 4</td>
</tr>
<tr>
<td rowspan="4">Template argument deduction for class templates</td>
<td><a href="https://wg21.link/p0091r3">P0091R3</a></td>
<td rowspan="2" class="full" align="center">Clang 5</td>
</tr>
<tr>
<td><a href="https://wg21.link/p0512r0">P0512R0</a></td>
</tr>
<tr>
<td><a href="https://wg21.link/p0620r1">P0620R0</a> (<a href="#dr">DR</a>)</td>
<td class="full" align="center">Clang 7</td>
</tr>
<tr>
<td><a href="https://wg21.link/p0702r1">P0702R1</a> (<a href="#dr">DR</a>)</td>
<td class="full" align="center">Clang 6</td>
</tr>
<tr>
<td>Non-type template parameters with <tt>auto</tt> type</td>
<td><a href="https://wg21.link/p0127r2">P0127R2</a></td>
<td class="full" align="center">Clang 4</td>
</tr>
<tr>
<td>Guaranteed copy elision</td>
<td><a href="https://wg21.link/p0135r1">P0135R1</a></td>
<td class="full" align="center">Clang 4</td>
</tr>
<tr>
<td rowspan=2>Stricter expression evaluation order</td>
<td><a href="https://wg21.link/p0145r3">P0145R3</a></td>
<td class="full" align="center" rowspan=2>Clang 4 <a href="#p0145">(9)</a></td>
</tr>
<tr>
<td><a href="https://wg21.link/p0400r0">P0400R0</a></td>
</tr>
<tr>
<td>Requirement to ignore unknown attributes</td>
<td><a href="https://wg21.link/p0283r2">P0283R2</a></td>
<td class="full" align="center">Yes</td>
</tr>
<tr>
<td><tt>constexpr</tt> <em>if-statement</em>s</td>
<td><a href="https://wg21.link/p0292r2">P0292R2</a></td>
<td class="full" align="center">Clang 3.9</td>
</tr>
<tr>
<td>Inline variables</td>
<td><a href="https://wg21.link/p0386r2">P0386R2</a></td>
<td class="full" align="center">Clang 3.9</td>
</tr>
<tr>
<td rowspan="3">Structured bindings</td>
<td><a href="https://wg21.link/p0217r3">P0217R3</a></td>
<td class="full" align="center">Clang 4</td>
</tr>
<tr>
<td><a href="https://wg21.link/p0961r1">P0961R1</a> (<a href="#dr">DR</a>)</td>
<td class="full" align="center">Clang 8</td>
</tr>
<tr>
<td><a href="https://wg21.link/p0969r0">P0969R0</a> (<a href="#dr">DR</a>)</td>
<td class="full" align="center">Clang 8</td>
</tr>
<tr>
<td>Separate variable and condition for <tt>if</tt> and <tt>switch</tt></td>
<td><a href="https://wg21.link/p0305r1">P0305R1</a></td>
<td class="full" align="center">Clang 3.9</td>
</tr>
<tr>
<td>Matching template template parameters to compatible arguments</td>
<td><a href="https://wg21.link/p0522r0">P0522R0</a></td>
<td class="partial" align="center">Partial <a href="#p0522">(10)</a></td>
</tr>
<tr>
<td>Removing deprecated dynamic exception specifications</td>
<td><a href="https://wg21.link/p0003r5">P0003R5</a></td>
<td class="full" align="center">Clang 4</td>
</tr>
<tr>
<td>Pack expansions in <em>using-declarations</em></td>
<td><a href="https://wg21.link/p0195r2">P0195R2</a></td>
<td class="full" align="center">Clang 4</td>
</tr>
</table>
<p>
<span id="n3922">(8): This is a backwards-incompatible change that is applied to
all language versions that allow type deduction from <tt>auto</tt>
(per the request of the C++ committee).
In Clang 3.7, a warning is emitted for all cases that would change meaning.
</span><br>
<span id="p0145">(9): Under the MS ABI, function parameters are destroyed from
left to right in the callee. As a result, function parameters in calls to
<tt>operator<<</tt>, <tt>operator>></tt>, <tt>operator->*</tt>,
<tt>operator&&</tt>, <tt>operator||</tt>, and <tt>operator,</tt>
functions using expression syntax are no longer guaranteed to be destroyed in
reverse construction order in that ABI.
This is not fully supported during constant expression evaluation until Clang 12.
</span><br>
<span id="p0522">(10): Despite being the resolution to a Defect Report, this
feature is disabled by default in all language versions, and can be enabled
explicitly with the flag <tt>-frelaxed-template-template-args</tt> in Clang 4
onwards.
The change to the standard lacks a corresponding change for template partial
ordering, resulting in ambiguity errors for reasonable and previously-valid
code. This issue is expected to be rectified soon.
</span>
</p>
</details>
<h2 id="cxx20">C++20 implementation status</h2>
<p>Clang has support for some of the features of the
<a href="https://www.iso.org/standard/79358.html">ISO C++ 2020 standard</a>.</p>
<p>You can use Clang in C++20 mode with the <code>-std=c++20</code> option
(use <code>-std=c++2a</code> in Clang 9 and earlier).</p>
<details open>
<summary>List of features and minimum Clang version with support</summary>
<table width="689" border="1" cellspacing="0">
<tr>
<th>Language Feature</th>
<th>C++20 Proposal</th>
<th>Available in Clang?</th>
</tr>
<tr>
<td>Default member initializers for bit-fields</td>
<td><a href="https://wg21.link/p0683r1">P0683R1</a></td>
<td class="full" align="center">Clang 6</td>
</tr>
<tr>
<td><tt>const&</tt>-qualified pointers to members</td>
<td><a href="https://wg21.link/p0704r1">P0704R1</a></td>
<td class="full" align="center">Clang 6</td>
</tr>
<tr>
<td>Allow <i>lambda-capture</i> <tt>[=, this]</tt></td>
<td><a href="https://wg21.link/p0409r2">P0409R2</a></td>
<td class="full" align="center">Clang 6</td>
</tr>
<tr>
<td rowspan="2"><tt>__VA_OPT__</tt> for preprocessor comma elision</td>
<td><a href="https://wg21.link/p0306r4">P0306R4</a></td>
<td class="full" align="center">Clang 6</td>
</tr>
<tr>
<td><a href="https://wg21.link/p1042r1">P1042R1</a></td>
<td class="full" align="center">Clang 9</td>
</tr>
<tr>
<td>Designated initializers</td>
<td><a href="https://wg21.link/p0329r4">P0329R4</a></td>
<td class="full" align="center">Clang 10</td>
</tr>
<tr>
<td><i>template-parameter-list</i> for generic lambdas</td>
<td><a href="https://wg21.link/p0428r2">P0428R2</a></td>
<td class="full" align="center">Clang 9</td>
</tr>
<tr id="p0734">
<td rowspan="13">Concepts</td>
<td><a href="https://wg21.link/p0734r0">P0734R0</a></td>
<td class="full" align="center">Clang 10</td>
</tr>
<tr>
<td><a href="https://wg21.link/p0857r0">P0857R0</a></td>
<td class="partial" align="center">
<details><summary>Partial</summary>
Constraining template template parameters is not yet supported.
</details>
</td>
</tr>
<tr>
<td><a href="https://wg21.link/p1084r2">P1084R2</a></td>
<td rowspan="2" class="full" align="center">Clang 10</td>
</tr>
<tr>
<td><a href="https://wg21.link/p1141r2">P1141R2</a></td>
</tr>
<tr>
<td><a href="https://wg21.link/p0848r3">P0848R3</a></td>
<td rowspan="1" class="none" align="center">No</td>
</tr>
<tr>
<td><a href="https://wg21.link/p1616r1">P1616R1</a></td>
<td rowspan="2" class="full" align="center">Clang 10</td>
</tr>
<tr>
<td><a href="https://wg21.link/p1452r2">P1452R2</a></td>
</tr>
<tr>
<td><a href="https://wg21.link/p1972r0">P1972R0</a></td>
<td rowspan="4" class="full" align="center">Clang 10</td>
</tr>
<tr>
<td><a href="https://wg21.link/p1980r0">P1980R0</a></td>
</tr>
<tr>
<td><a href="https://wg21.link/p2103r0">P2103R0</a></td>
</tr>
<tr>
<td><a href="https://wg21.link/p2493r0">P2493R0</a></td>
</tr>
<tr>
<td><a href="https://wg21.link/p2092r0">P2092R0</a></td>
<td rowspan="1" class="partial" align="center">
<details><summary>Partial</summary>
<tt>typename</tt> not yet optional (depends on P0634R3).
</details>
</td>
</tr>
<tr>
<td><a href="https://wg21.link/p2113r0">P2113R0</a></td>
<td rowspan="1" class="none" align="center">No</td>
</tr>
<tr>
<td>Range-based for statements with initializer</td>
<td><a href="https://wg21.link/p0614r1">P0614R1</a></td>
<td class="full" align="center">Clang 8</td>
</tr>
<tr>
<td>ADL and function templates that are not visible</td>
<td><a href="https://wg21.link/p0846r0">P0846R0</a></td>
<td class="full" align="center">Clang 9</td>
</tr>
<tr>
<td><tt>const</tt> mismatch with defaulted copy constructor</td>
<td><a href="https://wg21.link/p0641r2">P0641R2</a></td>
<td class="full" align="center">Clang 8</td>
</tr>
<tr>
<td rowspan="10">Consistent comparison (<tt>operator<=></tt>)</td>
<td><a href="https://wg21.link/p0515r3">P0515R3</a></td>
<td rowspan="8" class="full" align="center">Clang 10</td>
</tr>
<tr>
<td><a href="https://wg21.link/p0905r1">P0905R1</a></td>
</tr>
<tr>
<td><a href="https://wg21.link/p1120r0">P1120R0</a></td>
</tr>
<tr>
<td><a href="https://wg21.link/p1185r2">P1185R2</a></td>
</tr>
<tr>
<td><a href="https://wg21.link/p1186r3">P1186R3</a></td>
</tr>
<tr>
<td><a href="https://wg21.link/p1630r1">P1630R1</a></td>
</tr>
<tr>
<td><a href="https://wg21.link/p1946r0">P1946R0</a></td>
</tr>
<tr>
<td><a href="https://wg21.link/p1959r0">P1959R0</a></td>
</tr>
<tr>
<td><a href="https://wg21.link/p2002r1">P2002R1</a></td>
<td class="partial" align="center">Partial</td>
</tr>
<tr>
<td><a href="https://wg21.link/p2085r0">P2085R0</a></td>
<td class="full" align="center">Clang 14</td>
</tr>
<tr>
<td>Access checking on specializations</td>
<td><a href="https://wg21.link/p0692r1">P0692R1</a></td>
<td class="full" align="center">Clang 14</td>
</tr>
<tr>
<td>Default constructible and assignable stateless lambdas</td>
<td><a href="https://wg21.link/p0624r2">P0624R2</a></td>
<td class="full" align="center">Clang 8</td>
</tr>
<tr>
<td>Lambdas in unevaluated contexts</td>
<td><a href="https://wg21.link/p0315r4">P0315R4</a></td>
<td class="partial" align="center">
<details><summary>Partial</summary>
temp.deduct/9 is not implemented yet.
</details>
</td>
</tr>
<tr>
<td><tt>[[no_unique_address]]</tt> attribute</td>
<td><a href="https://wg21.link/p0840r2">P0840R2</a></td>
<td class="full" align="center">Clang 9</td>
</tr>
<tr>
<td><tt>[[likely]]</tt> and <tt>[[unlikely]]</tt> attributes</td>
<td><a href="https://wg21.link/p0479r5">P0479R5</a></td>
<td class="full" align="center">Clang 12</td>
</tr>
<tr>
<td><tt>typename</tt> optional in more contexts</td>
<td><a href="https://wg21.link/p0634r3">P0634R3</a></td>
<td class="none" align="center">No</td>
</tr>
<tr>
<td>Pack expansion in lambda <i>init-capture</i></td>
<td><a href="https://wg21.link/p0780r2">P0780R2</a></td>
<td class="full" align="center">Clang 9</td>
</tr>
<tr>
<td rowspan="2">Class types as non-type template parameters</td>
<td><a href="https://wg21.link/p0732r2">P0732R2</a></td>
<td rowspan="2" class="partial" align="center">Partial</td>
</tr>
<tr>
<td><a href="https://wg21.link/p1907r1">P1907R1</a></td>
</tr>
<tr>
<td>Destroying operator delete</td>
<td><a href="https://wg21.link/p0722r3">P0722R3</a></td>
<td class="full" align="center">Clang 6</td>
</tr>
<tr>
<td rowspan="7">Relaxations of <tt>constexpr</tt> restrictions</td>
<td><a href="https://wg21.link/p1064r0">P1064R0</a></td>
<td class="full" align="center">Clang 9</td>
</tr>
<tr>
<td><a href="https://wg21.link/p1002r1">P1002R1</a></td>
<td class="full" align="center">Clang 8</td>
</tr>
<tr>
<td><a href="https://wg21.link/p1327r1">P1327R1</a></td>
<td rowspan="2" class="full" align="center">Clang 9</td>
</tr>
<tr>
<td><a href="https://wg21.link/p1330r0">P1330R0</a></td>
</tr>
<tr>
<td><a href="https://wg21.link/p1331r2">P1331R2</a></td>
<td rowspan="3" class="full" align="center">Clang 10</td>
</tr>
<tr>
<td><a href="https://wg21.link/p1668r1">P1668R1</a></td>
</tr>
<tr>
<td><a href="https://wg21.link/p0784r7">P0784R7</a></td>
</tr>
<tr>
<td>Prohibit aggregates with user-declared constructors</td>
<td><a href="https://wg21.link/p1008r1">P1008R1</a></td>
<td class="full" align="center">Clang 8</td>
</tr>
<tr>
<td>Feature test macros</td>
<td><a href="https://wg21.link/p0941r2">P0941R2</a></td>
<td class="full" align="center"><a href="#sd6">(see below)</a></td>
</tr>
<tr>
<td><tt>explicit(bool)</tt></td>
<td><a href="https://wg21.link/p0892r2">P0892R2</a></td>
<td class="full" align="center">Clang 9</td>
</tr>
<tr>
<td>Signed integers are two's complement</td>
<td><a href="https://wg21.link/p1236r1">P1236R1</a></td>
<td class="full" align="center">Clang 9</td>
</tr>
<tr>
<td><tt>char8_t</tt></td>
<td><a href="https://wg21.link/p0482r6">P0482R6</a></td>
<td class="full" align="center">Clang 7 <a href="#p0482">(11)</a></td>
</tr>
<tr>
<td rowspan=2>Immediate functions (<tt>consteval</tt>)</td>
<td><a href="https://wg21.link/p1073r3">P1073R3</a></td>
<td class="unreleased" align="center">Clang 15</td>
</tr>
<tr>
<td><a href="https://wg21.link/p1937r2">P1937R2</a></td>
<td class="full" align="center">Clang 14</td>
</tr>
<tr>
<td><tt>std::is_constant_evaluated</tt></td>
<td><a href="https://wg21.link/p0595r2">P0595R2</a></td>
<td class="full" align="center">Clang 9</td>
</tr>
<tr>
<td>Nested inline namespaces</td>
<td><a href="https://wg21.link/p1094r2">P1094R2</a></td>
<td class="full" align="center">Clang 8</td>
</tr>
<tr>
<td rowspan="2">Structured binding extensions</td>
<td><a href="https://wg21.link/p1091r3">P1091R3</a></td>
<td rowspan="2" class="partial" align="center">Partial</td>
</tr>
<tr>
<td><a href="https://wg21.link/p1381r1">P1381R1</a></td>
</tr>
<tr>
<td rowspan="2">Stronger Unicode requirements</td>
<td><a href="https://wg21.link/p1041r4">P1041R4</a></td>
<td rowspan="2" class="full" align="center">Yes</td>
</tr>
<tr>
<td><a href="https://wg21.link/p1139r2">P1139R2</a></td>
</tr>
<tr>
<td rowspan="2">Parenthesized initialization of aggregates</td>
<td><a href="https://wg21.link/p0960r3">P0960R3</a></td>
<td rowspan="2" class="none" align="center">No</td>
</tr>
<tr>
<td><a href="https://wg21.link/p1975r0">P1975R0</a></td>
</tr>
<tr>
<td rowspan="10">Modules</td>
<td><a href="https://wg21.link/p1103r3">P1103R3</a></td>
<td class="unreleased" align="center">Clang 15</td>
</tr>
<tr>
<td><a href="https://wg21.link/p1766r1">P1766R1</a> (<a href="#dr">DR</a>)</td>
<td class="full" align="center">Clang 11</td>
</tr>
<tr>
<td><a href="https://wg21.link/p1811r0">P1811R0</a></td>
<td class="none" align="center">No</td>
</tr>
<tr>
<td><a href="https://wg21.link/p1703r1">P1703R1</a></td>
<td class="none" align="center">Subsumed by P1857</td>
</tr>
<tr>
<td><a href="https://wg21.link/p1874r1">P1874R1</a></td>
<td class="unreleased" align="center">Clang 15</td>
</tr>
<tr>
<td><a href="https://wg21.link/p1979r0">P1979R0</a></td>
<td class="none" align="center">No</td>
</tr>
<tr>
<td><a href="https://wg21.link/p1779r3">P1779R3</a></td>
<td class="unreleased" align="center">Clang 15</td>
</tr>
<tr>
<td><a href="https://wg21.link/p1857r3">P1857R3</a></td>
<td class="none" align="center">No</td>
</tr>
<tr>
<td><a href="https://wg21.link/p2115r0">P2115R0</a></td>
<td class="partial" align="center">Partial</td>
</tr>
<tr>
<td><a href="https://wg21.link/p1815r2">P1815R2</a></td>
<td class="partial" align="center">Partial</td>
</tr>
<tr>
<td>Coroutines</td>
<td><a href="https://wg21.link/p0912r5">P0912R5</a></td>
<td class="partial" align="center">
<details><summary>Partial</summary>
The optimizer does not yet handle TLS with
<tt>__attribute__((const))</tt> attribute correctly. There can be issues where the
coroutine may resume on a different thread. <br \>This feature requires further
analysis of the C++ Standard to determine what work is necessary for conformance.
</details></td>
</tr>
<tr>
<td>Deprecate <tt>a[b,c]</tt></td>
<td><a href="https://wg21.link/p1161r3">P1161R3</a></td>
<td class="full" align="center">Clang 9</td>
</tr>
<tr>
<td>Deprecate some problematic uses of <tt>volatile</tt></td>
<td><a href="https://wg21.link/p1152r4">P1152R4</a></td>
<td class="full" align="center">Clang 10</td>
</tr>
<tr>
<td><tt>[[nodiscard("with reason")]]</tt></td>
<td><a href="https://wg21.link/p1301r4">P1301R4</a></td>
<td class="full" align="center">Clang 9</td>
</tr>
<tr>
<td><tt>using enum</tt></td>
<td><a href="https://wg21.link/p1099r5">P1099R5</a></td>
<td class="full" align="center">Clang 13</td>
</tr>
<tr>
<td rowspan=2>Class template argument deduction for aggregates</td>
<td><a href="https://wg21.link/p1816r0">P1816R0</a></td>
<td rowspan=2 class="none" align="center">No</td>
</tr>
<tr>
<td><a href="https://wg21.link/p2082r1">P2082R1</a></td>
</tr>
<tr>
<td>Class template argument deduction for alias templates</td>
<td><a href="https://wg21.link/p1814r0">P1814R0</a></td>
<td class="none" align="center">No</td>
</tr>
<tr>
<td>Permit conversions to arrays of unknown bound</td>
<td><a href="https://wg21.link/p0388r4">P0388R4</a></td>
<td class="full" align="center">Clang 14</td>
</tr>
<tr>
<td><tt>constinit</tt></td>
<td><a href="https://wg21.link/p1143r2">P1143R2</a></td>
<td class="full" align="center">Clang 10</td>
</tr>
<tr>
<td>Pseudo-destructors end object lifetimes</td>
<td><a href="https://wg21.link/p0593r6">P0593R6</a> (<a href="#dr">DR</a>)</td>
<td class="full" align="center">Clang 11</td>
</tr>
<tr>
<td>More implicit moves</td>
<td><a href="https://wg21.link/p1825r0">P1825R0</a> (<a href="#dr">DR</a>)</td>
<td class="full" align="center">Clang 13</td>
</tr>
</table>
<p>
<span id="p0482">(11): Prior to Clang 8, this feature is not enabled by
<tt>-std=c++20</tt>, but can be enabled with <tt>-fchar8_t</tt>.
</span>
</p>
</details>
<h2 id="cxx23">C++2b implementation status</h2>
<p>Clang has support for some of the features of the C++ standard following
C++20, informally referred to as C++2b.</p>
<p>You can use Clang in C++2b mode with the <code>-std=c++2b</code> option.</p>
<details open>
<summary>List of features and minimum Clang version with support</summary>
<table width="689" border="1" cellspacing="0">
<tr>
<th>Language Feature</th>
<th>C++2b Proposal</th>
<th>Available in Clang?</th>
</tr>
<tr>
<td>Literal suffix <tt>uz</tt>, <tt>z</tt> for <tt>size_t</tt>, <tt>ssize_t</tt></td>
<td><a href="https://wg21.link/p0330r8">P0330R8</a></td>
<td class="full" align="center">Clang 13</td>
</tr>
<tr>
<td>Make <tt>()</tt> in lambdas optional in all cases</td>
<td><a href="https://wg21.link/p1102r2">P1102R2</a></td>
<td class="full" align="center">Clang 13</td>
</tr>
<tr>
<td>Simpler implicit move</td>
<td><a href="https://wg21.link/p2266r1">P2266R1</a></td>
<td class="full" align="center">Clang 13</td>
</tr>
<tr>
<td><tt>if consteval</tt></td>
<td><a href="https://wg21.link/P1938R3">P1938R3</a></td>
<td class="full" align="center">Clang 14</td>
</tr>
<tr>
<td>Allow duplicate attributes</td>
<td><a href="https://wg21.link/P2156R1">P2156R1</a></td>
<td class="full" align="center">Clang 13</td>
</tr>
<tr>
<td>Narrowing contextual conversions to bool</td>
<td><a href="https://wg21.link/P1401R5">P1401R5</a></td>
<td class="full" align="center">Clang 14</td>
</tr>
<tr>
<td>Trimming whitespaces before line splicing</td>
<td><a href="https://wg21.link/P2223R2">P2223R2</a></td>
<td class="full" align="center">Yes</td>
</tr>
<tr>
<td>Make declaration order layout mandated</td>
<td><a href="https://wg21.link/p1847r4">P1874R4</a></td>
<td class="full" align="center">Yes</td>
</tr>
<tr>
<td>C++ identifier syntax using UAX 31</td>
<td><a href="https://wg21.link/P1949R7">P1949R7</a></td>
<td class="full" align="center">Clang 14</td>
</tr>
<tr>
<td>Mixed string literal concatenation</td>
<td><a href="https://wg21.link/p2201r1">P2201R1</a></td>
<td class="full" align="center">Yes</td>
</tr>
<tr>
<td>Deducing this</td>
<td><a href="https://wg21.link/P0847R7">P0847R7</a></td>
<td class="none" align="center">No</td>
</tr>
<tr>
<td rowspan=2>Change scope of lambda trailing-return-type</td>
<td><a href="https://wg21.link/P2036R3">P2036R3</a></td>
<td rowspan=2 class="none" align="center">No</td>
</tr>
<tr>
<td><a href="https://wg21.link/P2579R0">P2579R0</a></td>
</tr>
<tr>
<td>Multidimensional subscript operator</td>
<td><a href="https://wg21.link/P2128R6">P2128R6</a></td>
<td class="unreleased" align="center">Clang 15</td>
</tr>
<tr>
<td>Non-literal variables (and labels and gotos) in constexpr functions</td>
<td><a href="https://wg21.link/P2242R3">P2242R3</a></td>
<td class="unreleased" align="center">Clang 15</td>
</tr>
<tr>
<td>Character encoding of diagnostic text</td>
<td><a href="https://wg21.link/P2246R1">P2246R1</a></td>
<td class="full" align="center">Yes</td>
</tr>
<tr>
<td>Character sets and encodings</td>
<td><a href="https://wg21.link/P2314R4">P2314R4</a></td>
<td class="full" align="center">Yes</td>
</tr>
<tr>
<td>Consistent character literal encoding</td>
<td><a href="https://wg21.link/P2316R2">P2316R2</a></td>
<td class="full" align="center">Yes</td>
</tr>
<tr>
<td>Add support for preprocessing directives elifdef and elifndef</td>
<td><a href="https://wg21.link/P2334R1">P2334R1</a></td>
<td class="full" align="center">Clang 13</td>
</tr>
<tr>
<td>Extend init-statement to allow alias-declaration</td>
<td><a href="https://wg21.link/P2360R0">P2360R0</a></td>
<td class="full" align="center">Clang 14</td>
</tr>
<tr>
<td>auto(x): decay-copy in the language</td>
<td><a href="https://wg21.link/P0849R8">P0849R8</a></td>
<td class="unreleased" align="center">Clang 15</td>
</tr>
<tr>
<td>Attributes on Lambda-Expressions</td>
<td><a href="https://wg21.link/P2173R1">P2173R1</a></td>
<td class="full" align="center">Clang 13</td>
</tr>
<tr>
<td><tt>constexpr</tt> for <tt><cmath></tt> and <tt><cstdlib></tt></td>
<td><a href="https://wg21.link/P0533R9">P0533R9</a></td>
<td class="none" align="center">No</td>
</tr>
<tr>
<td>Type trait to determine if a reference binds to a temporary</td>
<td><a href="https://wg21.link/P2255R2">P2255R2</a></td>
<td class="partial" align="center">
<details><summary>Partial</summary>
Clang provides a <tt>__reference_binds_to_temporary</tt> type trait
builtin, with which the library facility can be partially implemented.
Both <tt>__reference_constructs_from_temporary</tt> and
<tt>__reference_converts_from_temporary</tt> builtins should be
provided, following the normal cross-vendor convention to implement
traits requiring compiler support directly.
</details></td>
</td>
</tr>
<tr>
<td>The Equality Operator You Are Looking For</td>
<td><a href="https://wg21.link/P2468R2">P2468R2</a></td>
<td class="none" align="center">No</td>
</tr>
<tr>
<td>De-deprecating volatile compound operations</td>
<td><a href="https://wg21.link/P2327R1">P2327R1</a></td>
<td class="unreleased" align="center">Clang 15</td>
</tr>
<tr>
<td>Support for <code>#warning</code></td>
<td><a href="https://wg21.link/P2437R1">P2437R1</a></td>
<td class="full" align="center">Yes</td>
</tr>
<tr>
<td>Remove non-encodable wide character literals and multicharacter wide character literals</td>
<td><a href="https://wg21.link/P2362R3">P2362R3</a></td>
<td class="full" align="center">Clang 14</td>
</tr>
<tr>
<td>Labels at the end of compound statements</td>
<td><a href="https://wg21.link/P2324R2">P2324R2</a></td>
<td class="none" align="center">No</td>
</tr>
<tr>
<td>Delimited escape sequences</td>
<td><a href="https://wg21.link/P2290R3">P2290R3</a></td>
<td class="unreleased" align="center">Clang 15</td>
</tr>
<tr>
<td>Named universal character escapes</td>
<td><a href="https://wg21.link/P2071R2">P2071R2</a></td>
<td class="unreleased" align="center">Clang 15</td>
</tr>
<tr>
<td>Relaxing some constexpr restrictions</td>
<td><a href="https://wg21.link/P2448R2">P2448R2</a></td>
<td class="none" align="center">No</td>
</tr>
<tr>
<td>Using unknown pointers and references in constant expressions</td>
<td><a href="https://wg21.link/P2280R4">P2280R4</a></td>
<td class="none" align="center">No</td>
</tr>
<tr>
<td>static <code>operator()</code></td>
<td><a href="https://wg21.link/P1169R4">P1169R4</a></td>
<td class="none" align="center">No</td>
</tr>
<tr>
<td>Extended floating-point types and standard names</td>
<td><a href="https://wg21.link/P1467R9">P1467R9</a></td>
<td class="none" align="center">No</td>
</tr>
<tr>
<td>Class template argument deduction from inherited constructors</td>
<td><a href="https://wg21.link/P2582R1">P2582R1</a></td>
<td class="none" align="center">No</td>
</tr>
<tr>
<td>Portable assumptions</td>
<td><a href="https://wg21.link/P1774R8">P1774R8</a></td>
<td class="none" align="center">No</td>
</tr>
<tr>
<td>Support for UTF-8 as a portable source file encoding</td>
<td><a href="https://wg21.link/P2295R6">P2295R6</a></td>
<td class="unreleased" align="center">Clang 15</td>
</tr>
<tr>
<td><code>char8_t</code> Compatibility and Portability Fix</td>
<td><a href="https://wg21.link/P2513R3">P2513R3</a></td>
<td class="none" align="center">No</td>
</tr>
<tr>
<td>Relax requirements on <code>wchar_t</code> to match existing practices</td>
<td><a href="https://wg21.link/P2460R2">P2460R2</a></td>
<td class="full" align="center">Yes</td>
</tr>
<tr>
<td>Explicit lifetime management</td>
<td><a href="https://wg21.link/P2590R2">P2590R2</a></td>
<td class="none" align="center">No</td>
</tr>
</table>
</details>
<h2 id="dr">Defect reports</h2>
<p>Clang generally aims to implement resolutions to Defect Reports (bug fixes
against prior standards) retroactively, in all prior standard versions where
the fix is meaningful. Significant Defect Report changes to language features
after the publication of the relevant standard are marked (DR) in the above
table.</p>
<p>Clang also has a test suite for conformance to resolutions for issues on the
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_toc.html">C++ core issues list</a>,
most of which are considered Defect Reports.
<a href="cxx_dr_status.html">Implementation status for C++ core issues</a> based on
that test suite is tracked on a separate page.</p>
<h2 id="ts">Technical specifications and standing documents</h2>
<p>ISO C++ also publishes a number of documents describing additional language
and library features that are not part of standard C++.</p>
<details open>
<summary>List of features and minimum Clang version with support</summary>
<table width="689" border="1" cellspacing="0">
<tr>
<th>Document</th>
<th>Latest draft</th>
<th>Compiler flag</th>
<th>Available in Clang?</th>
</tr>
<tr id="sd6">
<td rowspan="7">SD-6: SG10 feature test recommendations</td>
<td rowspan="7"><a href="https://isocpp.org/std/standing-documents/sd-6-sg10-feature-test-recommendations">SD-6</a></td>
<td rowspan="7">N/A</td>
<td class="full" align="center">
Clang 3.4 (<a href="https://wg21.link/n3745">N3745</a>)</br>
</td>
</tr>
<tr>
<td class="full" align="center">
Clang 3.6 (<a href="https://wg21.link/n4200">N4200</a>)</a>
</td>
</tr>
<tr>
<td class="full" align="center">
Clang 4 (<a href="https://wg21.link/p0096r3">P0096R3</a>)</a>
</td>
</tr>
<tr>
<td class="full" align="center">
Clang 5 (<a href="https://wg21.link/p0096r4">P0096R4</a>)</a>
</td>
</tr>
<tr>
<td class="full" align="center">
Clang 7 (<a href="https://wg21.link/p0096r5">P0096R5</a>)</a>
</td>
</tr>
<tr>
<td class="full" align="center">
Clang 9 (<a href="https://wg21.link/p1353r0">P1353R0</a>)
</td>
</tr>
<tr>
<td class="full" align="center">
Clang 10 (<a href="https://wg21.link/p1902r1">P1902R1</a>)</a>
</td>
</tr>
<tr>
<td>[TS] Concepts</td>
<td><a href="https://wg21.link/p0121r0">P0121R0</a></td>
<td></td>
<td class="na" align="center">Superseded by <a href="#p0734">P0734R0</a></td>
</tr>
<tr>
<td rowspan="2">[TS] Coroutines</td>
<td rowspan="2"><a href="https://isocpp.org/files/papers/N4663.pdf">N4663</a></td>
<td><tt>-fcoroutines-ts<br>-stdlib=libc++</tt></td>
<td class="full" align="center">Clang 5</td>
</tr>
<tr>
<td><tt>-std=c++20<br>-stdlib=libc++</tt></td>
<td class="na" align="center">Superseded by <a href="#p0912">P0912R5</a></td>
</tr>
<tr>
<td>[TS] Library Fundamentals, Version 1 (invocation type traits)</td>
<td><a href="https://wg21.link/n4480">N4480</a></td>
<td>N/A</td>
<td class="none" align="center">No</td>
</tr>
<tr>
<td>[TS] Library Fundamentals, Version 2 (<tt>source_location</tt>)</td>
<td><a href="https://wg21.link/n4617">N4617</a></td>
<td>N/A</td>
<td class="full" align="center">Clang 9 (<a href="docs/LanguageExtensions.html#source-location-builtins">documentation</a>)</td>
</tr>
<tr>
<td>[TS] Modules</td>
<td><a href="https://wg21.link/n4720">N4720</a></td>
<td><tt>-fmodules-ts</tt></td>
<td class="na" align="center">Superseded by <a href="#p1103">P1103R3</a></td>
</tr>
<tr>
<td>[DRAFT TS] Reflection</td>
<td><a href="https://wg21.link/n4818">N4818</a></td>
<td></td>
<td class="none" align="center">No</td>
</tr>
<tr>
<td>[TS] Transactional Memory</td>
<td><a href="https://wg21.link/n4514">N4514</a></td>
<td></td>
<td class="none" align="center">No</td>
</tr>
</table>
</details>
</div>
</body>
</html>