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| <!--*********************************************************************--> |
| <h1>libc++ C++2a Status</h1> |
| <!--*********************************************************************--> |
| |
| <p>In July 2017, the C++ standard committee created a draft for the next version of the C++ standard, known here as "C++2a" (probably to be C++20).</p> |
| <p>This page shows the status of libc++; the status of clang's support of the language features is <a href="https://clang.llvm.org/cxx_status.html#cxx2a">here</a>.</p> |
| |
| <p>Reminder: Features in unreleased drafts of the standard are subject to change.</p> |
| |
| <p>The groups that have contributed papers: |
| <ul> |
| <li>LWG - Library working group</li> |
| <li>CWG - Core Language Working group</li> |
| <li>SG1 - Study group #1 (Concurrency working group)</li> |
| </ul> |
| </p> |
| |
| <h3>Paper Status</h3> |
| <table id="papers" border="1"> |
| <tr><th>Paper #</th><th>Group</th><th>Paper Name</th><th>Meeting</th><th>Status</th><th>First released version</th></tr> |
| <!-- |
| <tr><td><a href="https://wg21.link/n3346">3346</a></td><td>LWG</td><td>Terminology for Container Element Requirements - Rev 1</td><td>Kona</td><td>Complete</td><td>3.4</td></tr> |
| --> |
| <tr><td><a href="https://wg21.link/P0463R1">P0463R1</a></td><td>LWG</td><td>Endian just Endian</td><td>Toronto</td><td>Complete</td><td>7.0</td></tr> |
| <tr><td><a href="https://wg21.link/P0674R1">P0674R1</a></td><td>LWG</td><td>Extending make_shared to Support Arrays</td><td>Toronto</td><td></td><td></td></tr> |
| |
| <tr><td></td><td></td><td></td><td></td><td></td><td></td></tr> |
| <tr><td><a href="https://wg21.link/P0020R6">P0020R6</a></td><td>LWG</td><td>Floating Point Atomic</td><td>Albuquerque</td><td></td><td></td></tr> |
| <tr><td><a href="https://wg21.link/P0053R7">P0053R7</a></td><td>LWG</td><td>C++ Synchronized Buffered Ostream</td><td>Albuquerque</td><td></td><td></td></tr> |
| <tr><td><a href="https://wg21.link/P0202R3">P0202R3</a></td><td>LWG</td><td>Add constexpr modifiers to functions in <algorithm> and <utility> Headers</td><td>Albuquerque</td><td><I>In Progress</I></td><td>7.0</td></tr> |
| <tr><td><a href="https://wg21.link/P0415R1">P0415R1</a></td><td>LWG</td><td>Constexpr for <tt>std::complex</tt></td><td>Albuquerque</td><td><I>In Progress</I></td><td>7.0</td></tr> |
| <tr><td><a href="https://wg21.link/P0439R0">P0439R0</a></td><td>LWG</td><td>Make <tt>std::memory_order</tt> a scoped enumeration</td><td>Albuquerque</td><td></td><td></td></tr> |
| <tr><td><a href="https://wg21.link/P0457R2">P0457R2</a></td><td>LWG</td><td>String Prefix and Suffix Checking</td><td>Albuquerque</td><td>Complete</td><td>6.0</td></tr> |
| <tr><td><a href="https://wg21.link/P0550R2">P0550R2</a></td><td>LWG</td><td>Transformation Trait <tt>remove_cvref</tt></td><td>Albuquerque</td><td>Complete</td><td>6.0</td></tr> |
| <tr><td><a href="https://wg21.link/P0600R1">P0600R1</a></td><td>LWG</td><td>nodiscard in the Library</td><td>Albuquerque</td><td><I>In Progress</I></td><td>7.0</td></tr> |
| <tr><td><a href="https://wg21.link/P0616R0">P0616R0</a></td><td>LWG</td><td>de-pessimize legacy <numeric> algorithms with std::move</td><td>Albuquerque</td><td></td><td></td></tr> |
| <tr><td><a href="https://wg21.link/P0653R2">P0653R2</a></td><td>LWG</td><td>Utility to convert a pointer to a raw pointer</td><td>Albuquerque</td><td>Complete</td><td>6.0</td></tr> |
| <tr><td><a href="https://wg21.link/P0718R2">P0718R2</a></td><td>LWG</td><td>Atomic shared_ptr</td><td>Albuquerque</td><td></td><td></td></tr> |
| <tr><td><a href="https://wg21.link/P0767R1">P0767R1</a></td><td>CWG</td><td>Deprecate POD</td><td>Albuquerque</td><td>Complete</td><td>7.0</td></tr> |
| <tr><td><a href="https://wg21.link/P0768R1">P0768R1</a></td><td>CWG</td><td>Library Support for the Spaceship (Comparison) Operator</td><td>Albuquerque</td><td></td><td></td></tr> |
| <tr><td><a href="https://wg21.link/P0777R1">P0777R1</a></td><td>LWG</td><td>Treating Unnecessary <tt>decay</tt></td><td>Albuquerque</td><td>Complete</td><td>7.0</td></tr> |
| |
| <!-- <tr><td></td><td></td><td></td><td></td><td></td><td></td></tr> --> |
| </table> |
| |
| <p><i>[ Note: "Nothing to do" means that no library changes were needed to implement this change -- end note]</i></p> |
| |
| <p>The missing bits in P0600 are in [mem.res.class], [mem.poly.allocator.class], and [container.node.overview]</p> |
| |
| <p>The missing bits in P0202 are in <tt>copy</tt>, <tt>copy_backwards</tt>, <tt>move</tt>, and <tt>move_backwards</tt> (and the ones that call them: <tt>copy_n</tt>, <tt>rotate_copy</tt>, <tt>merge</tt>, <tt>set_union</tt>, <tt>set_difference</tt>, and <tt>set_symmetric_difference</tt>). This is because the first four algorithms have specializations that call <tt>memmove</tt> which is not constexpr. See <a href="https://bugs.llvm.org/show_bug.cgi?id=25165">Bug 25165</a></p> |
| |
| |
| <h3>Library Working group Issues Status</h3> |
| <!-- <I>Note: "NAD" means that the issue was deemed "Not a defect"</I> --> |
| <table id="issues" border="1"> |
| <tr><th>Issue #</th><th>Issue Name</th><th>Meeting</th><th>Status</th></tr> |
| <!-- |
| <tr><td><a href="https://wg21.link/LWG1214">1214</a></td><td>Insufficient/inconsistent key immutability requirements for associative containers</td><td>Urbana</td><td></td></tr> |
| --> |
| <tr><td><a href="https://wg21.link/LWG2070">2070</a></td><td><tt>allocate_shared</tt> should use <tt>allocator_traits<A>::construct</tt></td><td>Toronto</td><td>Resolved by <a href="https://wg21.link/P0674R1">P0674R1</a></td></tr> |
| <tr><td><a href="https://wg21.link/LWG2444">2444</a></td><td>Inconsistent complexity for <tt>std::sort_heap</tt></td><td>Toronto</td><td></td></tr> |
| <tr><td><a href="https://wg21.link/LWG2593">2593</a></td><td>Moved-from state of Allocators</td><td>Toronto</td><td></td></tr> |
| <tr><td><a href="https://wg21.link/LWG2597">2597</a></td><td><tt>std::log</tt> misspecified for complex numbers</td><td>Toronto</td><td></td></tr> |
| <tr><td><a href="https://wg21.link/LWG2783">2783</a></td><td><tt>stack::emplace()</tt> and <tt>queue::emplace()</tt> should return <tt>decltype(auto)</tt></td><td>Toronto</td><td>Complete</td></tr> |
| <tr><td><a href="https://wg21.link/LWG2932">2932</a></td><td>Constraints on parallel algorithm implementations are underspecified</td><td>Toronto</td><td></td></tr> |
| <tr><td><a href="https://wg21.link/LWG2937">2937</a></td><td>Is <tt>equivalent("existing_thing", "not_existing_thing")</tt> an error</td><td>Toronto</td><td>Complete</td></tr> |
| <tr><td><a href="https://wg21.link/LWG2940">2940</a></td><td><tt>result_of</tt> specification also needs a little cleanup</td><td>Toronto</td><td></td></tr> |
| <tr><td><a href="https://wg21.link/LWG2942">2942</a></td><td>LWG 2873's resolution missed <tt>weak_ptr::owner_before</tt></td><td>Toronto</td><td>Complete</td></tr> |
| <tr><td><a href="https://wg21.link/LWG2954">2954</a></td><td>Specialization of the convenience variable templates should be prohibited</td><td>Toronto</td><td>Complete</td></tr> |
| <tr><td><a href="https://wg21.link/LWG2961">2961</a></td><td>Bad postcondition for <tt>set_default_resource</tt></td><td>Toronto</td><td></td></tr> |
| <tr><td><a href="https://wg21.link/LWG2966">2966</a></td><td>Incomplete resolution of US 74</td><td>Toronto</td><td><i>Nothing to do</i></td></tr> |
| <tr><td><a href="https://wg21.link/LWG2974">2974</a></td><td>Diagnose out of bounds <tt>tuple_element/variant_alternative</tt></td><td>Toronto</td><td>Complete</td></tr> |
| |
| <tr><td></td><td></td><td></td><td></td></tr> |
| <tr><td><a href="https://wg21.link/LWG2779">2779</a></td><td>[networking.ts] Relax requirements on buffer sequence iterators</td><td>Albuquerque</td><td></td></tr> |
| <tr><td><a href="https://wg21.link/LWG2870">2870</a></td><td>Default value of parameter theta of polar should be dependent</td><td>Albuquerque</td><td>Complete</td></tr> |
| <tr><td><a href="https://wg21.link/LWG2935">2935</a></td><td>What should create_directories do when p already exists but is not a directory?</td><td>Albuquerque</td><td></td></tr> |
| <tr><td><a href="https://wg21.link/LWG2941">2941</a></td><td>[thread.req.timing] wording should apply to both member and namespace-level functions</td><td>Albuquerque</td><td><i>Nothing to do</i></td></tr> |
| <tr><td><a href="https://wg21.link/LWG2944">2944</a></td><td>LWG 2905 accidentally removed requirement that construction of the deleter doesn't throw an exception</td><td>Albuquerque</td><td><i>Nothing to do</i></td></tr> |
| <tr><td><a href="https://wg21.link/LWG2945">2945</a></td><td>Order of template parameters in optional comparisons</td><td>Albuquerque</td><td>Complete</td></tr> |
| <tr><td><a href="https://wg21.link/LWG2948">2948</a></td><td>unique_ptr does not define operator<< for stream output</td><td>Albuquerque</td><td>Complete</td></tr> |
| <tr><td><a href="https://wg21.link/LWG2950">2950</a></td><td>std::byte operations are misspecified</td><td>Albuquerque</td><td>Complete</td></tr> |
| <tr><td><a href="https://wg21.link/LWG2952">2952</a></td><td>iterator_traits should work for pointers to cv T</td><td>Albuquerque</td><td>Complete</td></tr> |
| <tr><td><a href="https://wg21.link/LWG2953">2953</a></td><td>LWG 2853 should apply to deque::erase too</td><td>Albuquerque</td><td></td></tr> |
| <tr><td><a href="https://wg21.link/LWG2958">2958</a></td><td>Moves improperly defined as deleted</td><td>Albuquerque</td><td></td></tr> |
| <tr><td><a href="https://wg21.link/LWG2964">2964</a></td><td>Apparently redundant requirement for dynamic_pointer_cast</td><td>Albuquerque</td><td></td></tr> |
| <tr><td><a href="https://wg21.link/LWG2965">2965</a></td><td>Non-existing path::native_string() in filesystem_error::what() specification</td><td>Albuquerque</td><td></td></tr> |
| <tr><td><a href="https://wg21.link/LWG2972">2972</a></td><td>What is is_trivially_destructible_v<int>?</td><td>Albuquerque</td><td>Complete</td></tr> |
| <tr><td><a href="https://wg21.link/LWG2976">2976</a></td><td>Dangling uses_allocator specialization for packaged_task</td><td>Albuquerque</td><td>Complete</td></tr> |
| <tr><td><a href="https://wg21.link/LWG2977">2977</a></td><td>unordered_meow::merge() has incorrect Throws: clause</td><td>Albuquerque</td><td></td></tr> |
| <tr><td><a href="https://wg21.link/LWG2978">2978</a></td><td>Hash support for pmr::string and friends</td><td>Albuquerque</td><td></td></tr> |
| <tr><td><a href="https://wg21.link/LWG2979">2979</a></td><td>aligned_union should require complete object types</td><td>Albuquerque</td><td>Complete</td></tr> |
| <tr><td><a href="https://wg21.link/LWG2980">2980</a></td><td>Cannot compare_exchange empty pointers</td><td>Albuquerque</td><td></td></tr> |
| <tr><td><a href="https://wg21.link/LWG2981">2981</a></td><td>Remove redundant deduction guides from standard library</td><td>Albuquerque</td><td></td></tr> |
| <tr><td><a href="https://wg21.link/LWG2982">2982</a></td><td>Making size_type consistent in associative container deduction guides</td><td>Albuquerque</td><td></td></tr> |
| <tr><td><a href="https://wg21.link/LWG2988">2988</a></td><td>Clause 32 cleanup missed one typename</td><td>Albuquerque</td><td></td></tr> |
| <tr><td><a href="https://wg21.link/LWG2993">2993</a></td><td>reference_wrapper<T> conversion from T&&</td><td>Albuquerque</td><td></td></tr> |
| <tr><td><a href="https://wg21.link/LWG2998">2998</a></td><td>Requirements on function objects passed to {forward_,}list-specific algorithms</td><td>Albuquerque</td><td><i>Nothing to do</i></td></tr> |
| <tr><td><a href="https://wg21.link/LWG3001">3001</a></td><td>weak_ptr::element_type needs remove_extent_t</td><td>Albuquerque</td><td></td></tr> |
| <tr><td><a href="https://wg21.link/LWG3024">3024</a></td><td>variant's copies must be deleted instead of disabled via SFINAE</td><td>Albuquerque</td><td></td></tr> |
| |
| <!-- <tr><td></td><td></td><td></td><td></td></tr> --> |
| </table> |
| |
| <p>Last Updated: 6-Mar-2018</p> |
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