C++23

The next generation of the C++ standard.

See: The current IS schedule for C++23 (2023-05-10).

New language features

New library features

New modules

• std and std.compat

New headers

• <expected>
• <flat_map>
• <flat_set>
• <generator>
• <mdspan>
• <print>
• <spanstream>
• <stacktrace>
• <stdfloat>

C compatibility headers:

• <stdatomic.h>

Defect reports

Compiler support

Main Article: C++23 compiler support.

C++23 core language features

C++23 feature	Paper(s)	GCC	Clang	MSVC	Apple Clang	EDG eccp	Intel C++	IBM XLC++	Sun/Oracle C++	Embarcadero C++ Builder	Cray	Nvidia HPC C++ (ex Portland Group/PGI)	Nvidia nvcc
Literal suffix for (signed) size_t	P0330R8	11	13		13.1.6*	6.5
Make () more optional for lambdas	P1102R2	11	13		13.1.6*	6.3
if consteval	P1938R3	12	14		14.0.0*	6.3
Removing Garbage Collection Support	P2186R2	12		19.30*		N/A
Narrowing contextual conversions in static_assert and constexpr if	P1401R5	9	13 (partial)* 14		14.0.0*
Trimming whitespaces before line splicing	P2223R2	Yes	Yes		Yes
Make declaration order layout mandated	P1847R4	Yes	Yes	Yes	Yes
Removing mixed wide string literal concatenation	P2201R1	Yes	Yes	Yes	Yes	Yes	Yes
Explicit object parameter (deducing this)	P0847R7			19.32* (partial)*		6.3
auto(x) and auto{x}	P0849R8	12	15		14.0.3*	6.4
Change scope of lambda trailing-return-type	P2036R3		17
#elifdef and #elifndef	P2334R1	12	13		13.1.6*	6.5
Non-literal variables (and labels and gotos) in constexpr functions	P2242R3	12	15		14.0.3*	6.3
Consistent character literal encoding	P2316R2	Yes	Yes	19.30*	Yes	Yes
Character sets and encodings	P2314R4	10	Yes		Yes
Extend init-statement (of for loop) to allow alias-declaration	P2360R0	12	14		14.0.0*
Multidimensional subscript operator	P2128R6	12	15		14.0.3*
Attributes on lambdas	P2173R1	9	13		13.1.6*
#warning	P2437R1	Yes*	Yes		Yes	6.5	Yes
Remove non-encodable wide character literals and multicharacter wide character literals	P2362R3	13	14
Labels at the end of compound statements	P2324R2	13	16			6.5
Delimited escape sequences	P2290R3	13	15
Named universal character escapes	P2071R2	13	15
Relaxing some constexpr restrictions	P2448R2	13	17 (partial)
Simpler implicit move	P2266R3	13	13
static operator()	P1169R4	13	16
Requirements for optional extended floating-point types	P1467R9	13		N/A		6.4
Class template argument deduction from inherited constructors	P2582R1
Attribute [[assume]]	P1774R8	13
Support for UTF-8 as a portable source file encoding	P2295R6	13*	15*	19.0 (Update 2)*
static operator[]	P2589R0	13	16
Permitting static constexpr variables in constexpr functions	P2647R1	13	16
Extending the lifetime of temporaries in range-based for loop initializer	P2718R0
DR20: Meaningful exports	P2615R0		17 (partial)
DR20: consteval needs to propagate up	P2564R0		17
DR: C++ Identifier Syntax using Unicode Standard Annex 31	P1949R7	12	14		14.0.0*	6.4
DR11: Allow duplicate attributes	P2156R1	11	13		13.1.6*	6.5
DR20: Adjusting the value of feature-test macro __cpp_concepts	P2493R0	12		19.32*		6.4
DR98: Relax requirements on wchar_t to match existing practices	P2460R2	Yes	Yes
DR: Using unknown pointers and references in constant expressions	P2280R4
DR20: The Equality Operator You Are Looking For	P2468R2	13	16
DR20: char8_t Compatibility and Portability Fix	P2513R4	13	16	19.34*
DR: Clarify reporting of diagnostic directives and allow static_assert of non-value-dependent expressions in a template context	CWG2518	13
C++23 feature	Paper(s)	GCC	Clang	MSVC	Apple Clang	EDG eccp	Intel C++	IBM XLC++	Sun/Oracle C++	Embarcadero C++ Builder	Cray	Nvidia HPC C++ (ex Portland Group/PGI)	Nvidia nvcc

C++23 library features

C++23 feature	Paper(s)	GCC libstdc++	Clang libc++	MSVC STL	Apple Clang	Sun/Oracle C++ Standard Library	Embarcadero C++ Builder Standard Library
Stacktrace library	P0881R7 P2301R1	12 (partial)*		19.34*
<stdatomic.h>	P0943R6	12	15	19.31*	14.0.3*
std::is_scoped_enum	P1048R1	11	12	19.30*	13.0.0*
std::basic_string::contains(), std::basic_string_view::contains()	P1679R3	11	12	19.30*	13.0.0*
std::to_underlying	P1682R3	11	13	19.30*	13.1.6*
Relaxing requirements for time_point<>::clock	P2212R2	N/A		N/A
Providing size feedback in the Allocator interface	P0401R6		15	19.30*	14.0.3*
<spanstream>: string-stream with std::span-based buffer	P0448R4	12		19.31*
std::out_ptr(), std::inout_ptr()	P1132R8			19.30*
constexpr type_info::operator==()	P1328R1	12	17	19.33** 19.34*
Iterator pair constructors for std::stack and std::queue	P1425R4	12	14	19.31*	14.0.3*
Non-deduction context for allocators in container deduction guides	P1518R2	12	13	19.31*	13.1.6*
ranges::starts_with() and ranges::ends_with()	P1659R3		17 (partial)*	19.31*
Prohibiting std::basic_string and std::basic_string_view construction from nullptr	P2166R1	12	13	19.30*	13.1.6*
std::invoke_r()	P2136R3	12	17	19.31*
Range constructor for std::basic_string_view	P1989R2	11	14	19.30*	14.0.3*
Default template arguments for std::pair's forwarding constructor	P1951R1		14	19.30*	14.0.3*
Remove Garbage Collection and Reachability-Based Leak Detection (library support)	P2186R2	12	14	19.30*	14.0.3*
zip: views::zip, views::zip_transform, views::adjacent, and views::adjacent_transform	P2321R2	13	15 (partial)*	19.33*(partial)*** 19.37*	14.0.3*
Heterogeneous erasure overloads for associative containers	P2077R3			19.32*
std::byteswap()	P1272R4	12	14	19.31*	14.0.3*
Printing volatile T*	P1147R1	11.3	14	19.31*	14.0.3*
basic_string::resize_and_overwrite()	P1072R10	12	14	19.31*	14.0.3*
Monadic operations for std::optional	P0798R8	12	14	19.32*	14.0.3*
std::move_only_function	P0288R9	12		19.32*
Add a conditional noexcept specification to std::exchange	P2401R0	12	14	19.25*	14.0.3*
Require std::span & std::basic_string_view to be TriviallyCopyable	P2251R1	Yes	Yes	Yes	Yes
Clarifying the status of the “C headers”	P2340R1	Yes	Yes	Yes	Yes
<expected>	P0323R12 P2549R1	12	16	19.33*
constexpr for <cmath> and <cstdlib>	P0533R9	4.6 (partial)*
std::unreachable()	P0627R6	12	15	19.32*	14.0.3*
Deprecating std::aligned_storage and std::aligned_union	P1413R3	13	16	19.33*
std::reference_constructs_from_temporary & std::reference_converts_from_temporary	P2255R2	13 (partial)*
constexpr std::unique_ptr	P2273R3	12	16	19.33*
Constructing containers and strings from ranges with ranges::to(), tagged constructors, insert and assign member functions	P1206R7		17	19.34*
Pipe support for user-defined range adaptors (ranges::range_adaptor_closure, std::bind_back)	P2387R3	13 (partial)*		19.34*
ranges::iota(), ranges::shift_left(), and ranges::shift_right()	P2440R1	13 (partial)*		19.34*
views::join_with	P2441R2	13		19.34*
views::chunk and views::slide	P2442R1	13		19.33*
views::chunk_by	P2443R1	13		19.33*
std::mdspan: a non-owning multidimensional array reference	P0009R18 P2599R2 P2604R0 P2613R1 P2763R1		17 (partial)*
<flat_map>	P0429R9
<flat_set>	P1222R4
ranges::find_last(), ranges::find_last_if(), and ranges::find_last_if_not()	P1223R5	13		19.36*
Freestanding Library: Easy <utility>, <ranges>, and <iterator>	P1642R11	13*		N/A
views::stride	P1899R3	13		19.34*
Compatibility between std::tuple and tuple-like objects	P2165R4		2.9 (partial)*	19.36* (partial)* 19.37*	partial*
Rectifying constant iterators, sentinels, and ranges	P2278R4	13		19.35* (partial)* 19.36*
Formatting Ranges	P2286R8		16
Improve default container formatting	P2585R1		16 (partial)* 17
Formatted output library <print>	P2093R14 P2539R3		17 (partial)*	19.37*
Formatting std::thread::id and std::stacktrace	P2693R1		17 (partial)*
constexpr for integral overloads of std::to_chars() and std::from_chars().	P2291R3	13	16	19.34*
ranges::contains() and ranges::contains_subrange()	P2302R4	13		19.34*
Ranges fold algorithms	P2322R6	13		19.35*
views::cartesian_product	P2374R4 P2540R1	13		19.37*
Adding move-only types support for comparison concepts	P2404R3			19.36*
Ranges iterators as inputs to non-ranges algorithms	P2408R5			19.34*
constexpr std::bitset	P2417R2	13	16	19.34*
basic_string::substr() &&	P2438R2		16	19.34*
views::as_rvalue	P2446R2	13	16	19.34*
Standard Library Modules	P2465R3		17 (partial)*	19.35* (partial)* 19.36*
std::forward_like()	P2445R1		16	19.34*
Support exclusive mode for std::fstream	P2467R1	12		19.36*
views::repeat	P2474R2	13	17	19.36*
Relaxing range adaptors to allow for move-only types	P2494R2		17	19.34*
std::basic_string_view range constructor should be explicit	P2499R0	12.2	16	19.34*
std::generator: synchronous coroutine generator for ranges	P2502R2 P2787R0
Add a conditional noexcept specification to std::apply	P2517R1	10		19.34*
Explicit lifetime management (std::start_lifetime_as)	P2590R2 P2679R2
Clarify handling of encodings in localized formatting of chrono types	P2419R2			19.34**
std::move_iterator should not always be input_iterator	P2520R0	12.3*	17*	19.34**
Deduction guides update for explicit object parameter call operators	LWG3617			19.34*
Deduction guides update for static operator()	P1169R4	13	16
Standard names and library support for extended floating-point types	P1467R9	13		19.37**
Monadic operations for std::expected	P2505R5	13	17	19.36*
views::enumerate	P2164R9	13		19.37*
std::is_implicit_lifetime	P2674R1
std::common_reference_t of std::reference_wrapper should be a reference type	P2655R3			19.37*
Disallowing user specialization of std::allocator_traits	P2652R2			19.37*
Deprecating std::numeric_limits::has_denorm	P2614R2			19.37*
std::barrier's phase completion guarantees	P2588R3			19.36*
Making Multi-Param Constructors Of views explicit	P2711R1		17 (partial)*	19.36**
Relaxing Ranges Just A Smidge	P2609R3			19.37*
Stashing Stashing Iterators For Proper Flattening	P2770R0			19.37*
DR17: std::visit() for classes derived from std::variant	P2162R2	11.3	13	19.20** 19.30*	13.1.6*
DR20: Conditionally borrowed ranges	P2017R1	11		19.30*
DR20: Repairing input range adaptors and std::counted_iterator	P2259R1	12		19.30*(partial)* 19.31*
DR20: views::join should join all views of ranges	P2328R1	11.2	15	19.30*	14.0.3*
DR20: view does not require default_initializable	P2325R3	11.3	16	19.30*
DR20: Range adaptor objects bind arguments by value	P2281R1	11	14	19.29 (16.10)* (partial)* 19.31*	14.0.3*
DR20: constexpr for std::optional and std::variant	P2231R1	11.3 (partial)* 12	13 (partial)*	19.31*	13.1.6* (partial).
DR20: views::lazy_split and redesigned views::split	P2210R2	12	16	19.31*
DR20: Fix ranges::istream_view	P2432R1	12	16	19.31*
DR20: view with ownership	P2415R2	12	14	19.31*	14.0.3*
DR20: Fixing locale handling in chrono formatters	P2372R3			19.31*
DR20: Cleaning up integer-class types	P2393R1			19.32*
DR20: std::format() improvements	P2216R3	13	14 (partial)* 15	19.32*	14.0.3*
DR20: Add support for non-const-formattable types to std::format	P2418R2	13	15	19.32*	14.0.3*
DR20: std::basic_format_string	P2508R1	13	15	19.35*	14.0.3*
DR20: Poison Pills are Too Toxic	P2602R2			19.36*
DR20: std::format fill character allowances	P2572R1		17	19.37*
C++23 feature	Paper(s)	GCC libstdc++	Clang libc++	MSVC STL	Apple Clang	Sun/Oracle C++ Standard Library	Embarcadero C++ Builder Standard Library

* - hover over a cell marked with the star * to see additional pop-up notes.
DRnn - the number nn after "DR" denotes target C++ revision the Defect Report is applied to, e.g., DR20 → C++20.