We\u2019re pleased to provide an update on C++23 support in the Microsoft C++ (MSVC) Build Tools. This blog post will cover the feature additions in MSVC Build Tools version 14.51, including C++23 language features, libraries, and ISO C++ Core Working Group (CWG) and Library Working Group (LWG) Issue resolutions. We\u2019ll also discuss the plans for completion of C++23 support in the MSVC compiler and how to make use of these latest feature updates.<\/p>\n
The following C++23 language features are now available under P2647R1<\/strong><\/a>\u00a0Static constexpr variables in constexpr functions<\/p>\n Static local variables can be declared at compile time:<\/p>\n This reduces friction when marking existing functions as P2448R2<\/strong><\/a>\u00a0Relaxing some constexpr restrictions<\/p>\n The declaration of a This means foo can be marked as This also protects against scenarios where bar is owned by a library and changing its The following features are improvements to character encoding to better support Unicode and interoperability for C++.<\/p>\n P2029R4<\/strong><\/a>\u00a0Numeric and universal character escapes in literals<\/p>\n P2071R2<\/strong><\/a> Named universal character escapes<\/p>\n P2314R4<\/strong><\/a>\u00a0Character sets and encodings<\/p>\n P1774R8<\/strong><\/a>\u00a0Portable assumptions<\/p>\n P2324R2<\/strong><\/a>\u00a0Labels at the end of compound statements (C compatibility)<\/p>\n P2582R1<\/strong><\/a>\u00a0CTAD from inherited constructors (wording)<\/p>\n P2615R1<\/strong><\/a>\u00a0Meaningful exports<\/p>\n MSVC Build Tools 14.51 also resolves the following Core Working Group (CWG)<\/strong> issues:<\/p>\n CWG 2355<\/a>\u00a0Deducing noexcept specifiers<\/p>\n CWG 2392<\/a>\u00a0new-expression size checks and constant evaluation<\/p>\n CWG 2405<\/a>\u00a0Additional type-dependent expressions<\/p>\n CWG 2479<\/a>\u00a0Missing specifications for consteval and constinit<\/p>\n CWG 2484<\/a>\u00a0char8_t \/ char16_t integral promotions<\/p>\n CWG 2490<\/a>\u00a0Restrictions on destruction in constant expressions<\/p>\n CWG 2491<\/a>\u00a0Export of typedef after first declaration<\/p>\n CWG 2518<\/a>\u00a0Conformance requirements and #error \/ #warning<\/p>\n CWG 2529<\/a>\u00a0Constant destruction of constexpr references<\/p>\n CWG 2538<\/a>\u00a0Ignoring standard attributes syntactically<\/p>\n CWG 2539<\/a>\u00a0Three-way comparison and floating-point strong ordering<\/p>\n CWG 2543<\/a>\u00a0constinit and optimized dynamic initialization<\/p>\n CWG 2597<\/a>\u00a0Replaceable allocation functions in the global module<\/p>\n CWG 2602<\/a>\u00a0consteval defaulted functions<\/p>\n CWG 2605<\/a>\u00a0Implicit-lifetime aggregates<\/p>\n CWG 2615<\/a>\u00a0Missing __has_cpp_attribute(assume)<\/p>\n CWG 2618<\/a>\u00a0Deduction excluding exception specifications<\/p>\n CWG 2627<\/a>\u00a0Bit-fields and narrowing conversions<\/p>\n CWG 2631<\/a>\u00a0Immediate function evaluation in default arguments<\/p>\n CWG 2640<\/a>\u00a0Extended characters in n-character sequences<\/p>\n CWG 2651<\/a>\u00a0Conversion function templates and noexcept<\/p>\n CWG 2664<\/a>\u00a0CTAD deduction failure for alias templates<\/p>\n On GitHub, the microsoft\/STL repo tracks its status with a high level of detail:<\/p>\n Notable library features that are newly available in MSVC Build Tools 14.51<\/strong>:<\/p>\n Other notable changes:<\/p>\n All of this has been possible thanks to our amazing GitHub contributors.<\/p>\n At this point, we have two remaining features for completion of support for C++23. Both of these features are in-progress and will land in an upcoming MSVC Build Tools 14.52 Preview update.<\/p>\n P2564R3<\/a> consteval needs to propagate up<\/p>\n P0533R9<\/a>\u00a0constexpr <cmath><\/p>\n Once the remaining C++23 features are completed, the Full support for C++23 IntelliSense support in Visual Studio 2026 is still in progress in time for MSVC Build Tools 14.52 becoming the default MSVC Build Tools version in Visual Studio 2026<\/p>\n We\u2019ve recently made major changes to our release processes, which will enable us to ship fixes and updates to MSVC Build Tools Previews with greater frequency (approximately weekly) than before.<\/p>\n Please try out the new MSVC Build Tools 14.51 Preview<\/a> features . We\u2019d love your feedback on these features using the Your feedback can help us address any bugs and improve build and runtime performance. To submit feedback, use the Help > Send Feedback menu from the IDE, or navigate directly to Visual Studio Developer Community<\/a>. For the STL, specifically, please report feedback directly to us on the STL GitHub (https:\/\/github.com\/microsoft\/STL\/issues<\/a>).<\/p>\n Finally, I would like to thank Stephan T. Lavavej and RanDair Porter for their content contributions to this blog post.<\/p>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n","protected":false},"excerpt":{"rendered":" We\u2019re pleased to provide an update on C++23 support in the Microsoft C++ (MSVC) Build Tools. This blog post will cover the feature additions in MSVC Build Tools version 14.51, including C++23 language features, libraries, and ISO C++ Core Working Group (CWG) and Library Working Group (LWG) Issue resolutions. We\u2019ll also discuss the plans for […]<\/p>\n","protected":false},"author":44789,"featured_media":35994,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[1],"tags":[],"class_list":["post-36397","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-cplusplus"],"acf":[],"blog_post_summary":" We\u2019re pleased to provide an update on C++23 support in the Microsoft C++ (MSVC) Build Tools. This blog post will cover the feature additions in MSVC Build Tools version 14.51, including C++23 language features, libraries, and ISO C++ Core Working Group (CWG) and Library Working Group (LWG) Issue resolutions. We\u2019ll also discuss the plans for […]<\/p>\n","_links":{"self":[{"href":"https:\/\/devblogs.microsoft.com\/cppblog\/wp-json\/wp\/v2\/posts\/36397","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/devblogs.microsoft.com\/cppblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/devblogs.microsoft.com\/cppblog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/cppblog\/wp-json\/wp\/v2\/users\/44789"}],"replies":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/cppblog\/wp-json\/wp\/v2\/comments?post=36397"}],"version-history":[{"count":1,"href":"https:\/\/devblogs.microsoft.com\/cppblog\/wp-json\/wp\/v2\/posts\/36397\/revisions"}],"predecessor-version":[{"id":36420,"href":"https:\/\/devblogs.microsoft.com\/cppblog\/wp-json\/wp\/v2\/posts\/36397\/revisions\/36420"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/cppblog\/wp-json\/wp\/v2\/media\/35994"}],"wp:attachment":[{"href":"https:\/\/devblogs.microsoft.com\/cppblog\/wp-json\/wp\/v2\/media?parent=36397"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/cppblog\/wp-json\/wp\/v2\/categories?post=36397"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/cppblog\/wp-json\/wp\/v2\/tags?post=36397"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}\/std:c++23preview<\/code> and \/std:c++latest<\/code> in the MSVC Build Tools 14.51 Preview. An update of the documentation on learn.microsoft.com<\/a> to reflect these additions is scheduled before this version transitions to full support<\/a>:<\/p>\nCompile-time evaluation<\/h4>\n
constexpr char xdigit(int n)\r\n{\r\n static constexpr char digits[] = \"0123456789abcdef\";\r\n return digits[n];\r\n}\r\n<\/code><\/pre>\nconstexpr<\/code>. Users will no longer see an error when evaluating the function at compile time, so the static variable gets to remain locally scoped. And because the variable has static storage duration, it is much easier to optimize the run time version of the function.<\/p>\nconstexpr<\/code> function no longer fails if it’s decidedly unable to run at compile time.<\/p>\nvoid bar();\r\n\r\n\/\/ Now accepted, but only executable at run time\r\nconstexpr void foo()\r\n{\r\n bar();\r\n}<\/code><\/pre>\nconstexpr<\/code> without being penalized for its definition. It can still be used at run time. At compile time, it will fail when attempting to call bar.<\/p>\nconstexpr<\/code>-ness could make foo ill-formed, regardless of how foo is used.<\/p>\nUnicode support<\/h4>\n
Other C++23 Features<\/h4>\n
CWG Issue Resolutions<\/h2>\n
C++23 Library Features<\/strong><\/h2>\n
\n
\n
\n
\n
<regex><\/code> to fix long-standing correctness and performance problems that have been present since its initial implementation in VS 2008 SP1. After almost two decades, the stack overflows are finally fixed!<\/li>\n<hash_map><\/code>, <hash_set><\/code>, <experimental\/filesystem><\/code>, stdext::checked_array_iterator<\/code>, and stdext::unchecked_array_iterator<\/code>.<\/li>\n<\/ul>\nMSVC Build Tools 14.52 Previews and remaining C++23 Features<\/strong><\/h2>\n
Completion of C++23 and \/std:c++23<\/h4>\n
\/std:c++23<\/code> switch will be added in upcoming MSVC Build Tools 14.52 Preview releases. At that point in time, \/std:c++23preview<\/code> will be deprecated.<\/p>\n\/std:c++23<\/code> will begin once MSVC Build Tools 14.52 becomes the default (non-Preview) version in a Visual Studio 2026 Insiders release. Please see New release cadence and support lifecycle for Microsoft C++ Build Tools – C++ Team Blog<\/a> for additional details.<\/p>\nIntelliSense Support<\/h4>\n
Conclusion<\/h1>\n
\/std:c++23preview<\/code> switch.<\/p>\n