C++20

 

C++

컴파일러 지원

Freestanding and hosted

언어

표준 라이브러리 헤더

명명된 요구사항

Feature test macros (C++20)

언어 지원 라이브러리

개념 (C++20)

Diagnostics library

유틸리티 라이브러리

문자열 라이브러리

컨테이너 라이브러리

반복자 라이브러리

범위 라이브러리 (C++20)

알고리즘 라이브러리

수치 라이브러리

지역화 라이브러리

입/출력 라이브러리

파일시스템 라이브러리 (C++17)

정규 표현식 라이브러리 (C++11)

아토믹 연산 라이브러리 (C++11)

쓰레드 지원 라이브러리 (C++11)

Technical specifications

Symbols index

외부 라이브러리들

 

Versions

C++98

C++03

C++11

C++14

C++17

C++20

C++23

Current Status

 

The current revision of the C++ standard

New language features

• Feature test macros
• 3-way comparison operator <=> and operator==() = default
• designated initializers
• init-statements and initializers in range-for
• char8_t
• New attributes: [[no_unique_address]], [[likely]], [[unlikely]]
• pack-expansions in lambda init-captures
• removed the requirement to use typename to disambiguate types in many contexts
• consteval, constinit
• further relaxed constexpr
• signed integers are 2's complement
• aggregate initialization using parentheses
• Coroutines
• Modules
• Constraints and concepts
• Abbreviated function templates
• DR: array new can deduce array size

New library features

New headers

• <concepts>
• <coroutine>
• <compare>
• <version>
• <source_location>
• <format>
• <span>
• <ranges>
• <bit>
• <numbers>
• <syncstream>

in Thread support library:

• <stop_token>
• <semaphore>
• <latch>
• <barrier>

Library features

• Library feature-test macros
• Formatting library
• Calendar and Time Zone library
• source_location
• span
• endian
• array support for make_shared
• remove_cvref
• to_address
• floating-point atomics, shared_ptr atomics
• thread-coordination classes: barrier, latch, and counting_semaphore
• jthread and thread cancellation classes: stop_token, stop_source, and stop_callback
• basic_osyncstream
• u8string and other char8_t uses
• constexpr for <algorithm>, <utility>, <complex>
• string::starts_with / ends_with and string_view::starts_with / ends_with
• assume_aligned
• bind_front
• c8rtomb/mbrtoc8
• make_obj_using_allocator etc
• make_shared_for_overwrite/make_unique_for_overwrite
• heterogeneous lookup in unordered associative containers
• polymorphic_allocator with additional member functions and byte as its default template argument
• execution::unseq
• midpoint and lerp
• ssize
• is_bounded_array, is_unbounded_array
• Ranges
• uniform container erasure: std::erase/std::erase_if, e.g. std::erase(std::list) or erase_if(std::map) etc
• Mathematical constants in <numbers>

Compiler support

Main Article: C++ compiler support

C++20 core language features

C++20 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
Allow lambda-capture [=, this]	P0409R2	8	6	19.22*	10.0.0*	5.1						20.7
__VA_OPT__	P0306R4 P1042R1	8 (partial)* 10 (partial)* 12	9	19.25*	11.0.3*	5.1						20.7
Designated initializers	P0329R4	4.7 (partial)* 8	3.0 (partial)* 10	19.21*	(partial)*	5.1						20.7
template-parameter-list for generic lambdas	P0428R2	8	9	19.22*	11.0.0*	5.1						20.7
Default member initializers for bit-fields	P0683R1	8	6	19.25*	10.0.0*	5.1						20.7
Initializer list constructors in class template argument deduction	P0702R1	8	6	19.14*	Yes	5.0						20.7
const&-qualified pointers to members	P0704R1	8	6	19.0 (2015)*	10.0.0*	5.1						20.7
Concepts	P0734R0	6 (TS only) 10	10	19.23* (partial)* 19.30*	12.0.0* (partial)	6.1						20.11
Lambdas in unevaluated contexts	P0315R4	9	13 (partial)* 14 (partial)*	19.28 (16.8)*
Three-way comparison operator	P0515R3	10	8 (partial) 10	19.20*		5.1						20.7
DR: Simplifying implicit lambda capture	P0588R1	8		19.24*		5.1						20.7
init-statements for range-based for	P0614R1	9	8	19.25*	11.0.0*	6.0						20.11
Default constructible and assignable stateless lambdas	P0624R2	9	8	19.22*	10.0.1*	5.1						20.7
const mismatch with defaulted copy constructor	P0641R2	9	8	19.0 (2015)*	10.0.1*	5.1						20.7
Access checking on specializations	P0692R1	Yes	8 (partial) 14	19.26*	10.0.1* (partial)	5.1						20.7
ADL and function templates that are not visible	P0846R0	9	9	19.21*	11.0.3*	5.1						20.7
DR: Specify when constexpr function definitions are needed for constant evaluation	P0859R0	5.2 (partial)* 9	8	19.27* (partial)* 19.31*
Attributes [[likely]] and [[unlikely]]	P0479R5	9	12	19.26*	13.0.0*	5.1						20.7
Make typename more optional	P0634R3	9		19.29 (16.10)*		5.1						20.7
Pack expansion in lambda init-capture	P0780R2	9	9	19.22*	11.0.3*	6.1						20.11
Attribute [[no_unique_address]]	P0840R2	9	9	19.28 (16.9)**	11.0.3*	5.1						20.7
Conditionally Trivial Special Member Functions	P0848R3	10		19.28 (16.8)*		6.1						20.11
DR: Relaxing the structured bindings customization point finding rules	P0961R1	8	8	19.21*	10.0.1*	5.1						20.7
DR: Relaxing the range-for loop customization point finding rules	P0962R1	8	8	19.25*		5.1						20.7
DR: Allow structured bindings to accessible members	P0969R0	8	8	19.21*	10.0.1*	5.1						20.7
Destroying operator delete	P0722R3	9	6	19.27*	10.0.0*	6.1						20.11
Class types in non-type template parameters	P0732R2	9	12 (partial)	19.26*(partial)* 19.28 (16.9)*		6.2
Deprecate implicit capture of this via [=]	P0806R2	9	7	19.22*		5.1						20.7
explicit(bool)	P0892R2	9	9	19.24*	11.0.3*	5.1						20.7
Integrating feature-test macros	P0941R2	5	3.4	19.15* (partial) 19.20*	Yes	5.0						20.7
Prohibit aggregates with user-declared constructors	P1008R1	9	8	19.20*	10.0.1*	5.1						20.7
constexpr virtual function	P1064R0	9	9	19.28 (16.9)*	11.0.3*	5.1						20.7
Consistency improvements for comparisons	P1120R0	10	8 (partial) 10	19.22*	10.0.1* (partial)	5.1						20.7
char8_t	P0482R6	9	7	19.22*	10.0.0*	5.1						20.7
std::is_constant_evaluated()	P0595R2	9	9	19.25*	11.0.3*	5.1	19.1
constexpr try-catch blocks	P1002R1	9	8	19.25*	10.0.1*	5.1						20.7
Immediate functions (consteval)	P1073R3	10 (partial)* 11	11 (partial) 14 (partial)*	19.28 (16.8)** (partial) 19.29 (16.10)*		5.1						20.7
Nested inline namespaces	P1094R2	9	8	19.27*	10.0.1*	5.1						20.7
Yet another approach for constrained declarations	P1141R2	10	10	19.26* (partial) 19.28 (16.9)*		6.1						20.11
Signed integers are two's complement	P1236R1	9	9	Yes	11.0.3*	N/A						yes
dynamic_cast and polymorphic typeid in constant expressions	P1327R1	10	9	19.29 (16.10)*	11.0.3*	5.1						20.7
Changing the active member of a union inside constexpr	P1330R0	9	9	19.10*	11.0.3*	5.1						20.7
Coroutines	P0912R5	10	8 (partial)	19.0 (2015)* (partial) 19.10* (TS only) 19.28 (16.8)*	10.0.1* (partial)	5.1
Parenthesized initialization of aggregates	P0960R3	10		19.28 (16.8)*		5.1						20.7
DR: Array size deduction in new-expressions	P1009R2	11	9	19.27*	11.0.3*	5.1						20.7
Modules	P1103R3	11 (partial)	8 (partial)	19.0 (2015)* (partial) 19.10* (TS only) 19.28 (16.8)*	10.0.1* (partial)
Stronger Unicode requirements	P1041R4 P1139R2	10	Yes	19.0 (2015)* (P1041R4) 19.26* (P1139R2)	Yes	N/A
<=> != ==	P1185R2	10	10	19.22*		5.1						20.7
DR: Explicitly defaulted functions with different exception specifications	P1286R2	10	9	19.28 (16.8)*	11.0.3*	5.1						20.7
Lambda capture and storage class specifiers of structured bindings	P1091R3 P1381R1	10	8 (partial)	19.11*(P1381R1) 19.24*(P1091R3)	10.0.1* (partial)	5.1						20.7
Permit conversions to arrays of unknown bound	P0388R4	10	14	19.27*		6.0						20.11
constexpr container operations	P0784R7	10	10	19.28 (16.9)*		6.0						20.11
Deprecating some uses of volatile	P1152R4	10	10	19.27*		6.0						20.11
constinit	P1143R2	10	10	19.29 (16.10)*		6.1						20.11
Deprecate comma operator in subscripts	P1161R3	10	9	19.25*	11.0.3*	6.0						20.11
[[nodiscard]] with message	P1301R4	10	9	19.25*	11.0.3*	6.0						20.11
Trivial default initialization in constexpr functions	P1331R2	10	10	19.27*		6.1						20.11
Unevaluated asm-declaration in constexpr functions	P1668R1	10	10	19.28 (16.9)*		6.1						20.11
using enum	P1099R5	11	13	19.24*		6.3
Synthesizing three-way comparison for specified comparison category	P1186R3	11	10	19.24*		6.0						20.11
DR: [[nodiscard]] for constructors	P1771R1	10	9	19.24*	11.0.3*	6.0						20.11
Class template argument deduction for alias templates	P1814R0	10		19.27*
Class template argument deduction for aggregates	P1816R0 P2082R1	10(P1816R0) 11(P2082R1)		19.27*
DR: Implicit move for more local objects and rvalue references	P1825R0	11*	13	19.24*		6.0						20.11
Allow defaulting comparisons by value	P1946R0	10	10	19.25*		6.1						20.11
Remove std::weak_equality and std::strong_equality	P1959R0	10	10	19.25*		6.1						20.11
Inconsistencies with non-type template parameters	P1907R1	10 (partial) 11	12 (partial)	19.26*		6.2
DR: Pseudo-destructors end object lifetimes	P0593R6	11	11	Yes		N/A
DR: Converting from T* to bool should be considered narrowing	P1957R2	10* 11*	11	19.27*		6.1
C++20 feature	Paper(s)	GCC	Clang	MSVC	Apple Clang	EDG eccp	Intel C++	IBM XLC++	Sun/Oracle C++	Embarcadero C++ Builder	Cray	Nvidia HPC C++	Nvidia nvcc

C++20 library features

C++20 feature	Paper(s)	GCC libstdc++	Clang libc++	MSVC STL	Apple Clang	Sun/Oracle C++ Standard Library	Embarcadero C++ Builder Standard Library	Cray C++ Standard Library
std::endian	P0463R1	8	7	19.22*	10.0.0*
Extending std::make_shared() to support arrays	P0674R1			19.27*
Floating-point atomic	P0020R6	10		19.22*
Synchronized buffered (std::basic_osyncstream)	P0053R7	11		19.29 (16.10)*
constexpr for <algorithm> and <utility>	P0202R3	10	8 (partial) 12	19.26*	10.0.1* (partial) 12.0.5*
More constexpr for <complex>	P0415R1	9	7 (partial)	19.27*	10.0.0* (partial)
Make std::memory_order a scoped enumeration	P0439R0	9	9	19.25*	11.0.3*
String prefix and suffix checking: string(_view) ::starts_with/ends_with	P0457R2	9	6	19.21*	10.0.0*
Library support for operator<=> <compare>	P0768R1	10	7 (partial) 12	19.20* (partial) 19.28 (16.9)*	10.0.0* (partial)
std::remove_cvref	P0550R2	9	6	19.20*	10.0.0*
[[nodiscard]] in the standard library	P0600R1	9	7 (partial)	19.13* (partial) 19.22*	10.0.0* (partial)
Using std::move in numeric algorithms	P0616R0	9	12	19.23*
Utility to convert a pointer to a raw pointer	P0653R2	8	6	19.22*	Yes
Atomic std::shared_ptr and std::weak_ptr	P0718R2			19.27*
std::span	P0122R7	10	7	19.26*	10.0.0*
Calendar and timezone	P0355R7	11 (partial)	7 (partial)	19.29 (16.10)*	10.0.0* (partial)
<version>	P0754R2	9	7	19.22*	10.0.0*
Comparing unordered containers	P0809R0	Yes	Yes	16.0*	Yes
ConstexprIterator requirements	P0858R0	9	12	19.11*
std::basic_string::reserve() should not shrink	P0966R1	11	8	19.25*	10.0.1*
Atomic Compare-And-Exchange with padding bits	P0528R3			19.28 (16.8)*
std::atomic_ref	P0019R8	10		19.28 (16.8)*
contains() member function of associative containers, e.g. std::map::contains()	P0458R2	9	9 (partial)* 13	19.21*	11.0.3*
DR: Guaranteed copy elision for piecewise construction	P0475R1	9	Yes	19.29 (16.10)*	Yes
std::bit_cast()	P0476R2	11	14	19.27*
Integral power-of-2 operations: std::bit_ceil(), std::bit_floor(), std::bit_width(), std::has_single_bit()	P0556R3 P1956R1	9 (P0556R3) 10 (P1956R1)	9 (P0556R3) 12 (P1956R1)	19.25* (P0556R3)* 19.27* (P1956R1)* 19.28 (16.8)*
Improving the return value of erase-like algorithms	P0646R1	9	10	19.21*
std::destroying_delete	P0722R3	9	9	19.27*	11.0.3*
std::is_nothrow_convertible	P0758R1	9	9	19.23*	11.0.3*
Add std::shift_left/right to <algorithm>	P0769R2	10	12	19.21*
Constexpr for std::swap() and swap related functions	P0879R0	10	12 (partial) 13	19.26*
std::type_identity	P0887R1	9	8	19.21*	10.0.1*
Concepts library	P0898R3	10	13	19.23*	12.0.0* (partial)
constexpr comparison operators for std::array	P1023R0	10	8	19.27*	10.0.1*
std::unwrap_ref_decay and std::unwrap_reference	P0318R1	9	8	19.21*	10.0.1*
std::bind_front()	P0356R5	9	13	19.25*
std::reference_wrapper for incomplete types	P0357R3	9	8	19.26*	10.0.1*
Fixing operator>>(basic_istream&, CharT*)	P0487R1	11	8	19.23*	10.0.1*
Library support for char8_t	P0482R6	9	8 (partial)*	19.22*
Utility functions to implement uses-allocator construction	P0591R4	9		19.29 (16.10)*
DR: std::variant and std::optional should propagate copy/move triviality	P0602R4	8.3	8	19.11*	10.0.1*
A sane std::variant converting constructor	P0608R3	10	9	19.29 (16.10)*	11.0.3*
std::function's move constructor should be noexcept	P0771R1	7.2	6	19.22*	Yes
The One Ranges Proposal	P0896R4	10	13 (partial)	19.29 (16.10)*
Heterogeneous lookup for unordered containers	P0919R3 P1690R1	11	12	19.23* (P0919R3) 19.25* (P1690R1)
<chrono> zero(), min(), and max() should be noexcept	P0972R0	9	8	19.14*	10.0.1*
constexpr in std::pointer_traits	P1006R1	9	8	19.26*	10.0.1*
std::assume_aligned()	P1007R3	9* 11		19.28 (16.9)*
Smart pointer creation with default initialization (e.g. make_unique_for_overwrite)	P1020R1 P1973R1			19.28 (16.9)*
Misc constexpr bits	P1032R1	10	13	19.28 (16.8)*
Remove comparison operators of std::span	P1085R2	10	8	19.26*	10.0.1*
Make stateful allocator propagation more consistent for operator+(basic_string)	P1165R1	10		19.26*
Consistent container erasure, e.g. std::erase(std::vector), or std::erase_if(std::map)	P1209R0 P1115R3	9 (P1209R0) 10 (P1115R3)	8 (P1209R0) 11 (P1115R3)	19.25* (P1209R0) 19.27* (P1115R3)	10.0.1* (P1209R0)
Standard library header units	P1502R1	11		19.29 (16.10)*
polymorphic_allocator<> as a vocabulary type	P0339R6	9		19.28 (16.9)*
std::execution::unseq	P1001R2	9		19.28 (16.8)*
std::lerp() and std::midpoint()	P0811R3	9	9	19.23* (partial) 19.28 (16.8)*	11.0.3*
Usability enhancements for std::span	P1024R3	10	9* 14	19.26*	11.0.3*
DR: Make create_directory() intuitive	P1164R1	8.3	12	19.20*
std::ssize() and unsigned extent for std::span	P1227R2	10	9	19.25*	11.0.3*
Traits for (un)bounded arrays	P1357R1	9	9	19.25*	11.0.3*
std::to_array()	P0325R4	10	10	19.25*
Efficient access to std::basic_stringbuf’s buffer	P0408R7	11		19.29 (16.10)*
Layout-compatibility and pointer-interconvertibility traits	P0466R5	12		19.29 (16.10)**
Bit operations: std:: rotl(), rotr(), countl_zero(), countl_one(), countr_zero(), countr_one(), popcount()	P0553R4	9	9	19.25** 19.28 (16.8)*	11.0.3*
Mathematical constants	P0631R8	10	11	19.25*
Text formatting	P0645R10		14 (partial)*	19.29 (16.10)*
std::stop_token and std::jthread	P0660R10	10		19.28 (16.9)*
constexpr std::allocator and related utilities	P0784R7	10	12	19.29 (16.10)*
constexpr std::string	P0980R1	12		19.29 (16.10)* 19.30**
constexpr std::vector	P1004R2	12		19.29 (16.10)* 19.30**
Input range adaptors	P1035R7	10		19.29 (16.10)*
constexpr std::invoke() and related utilities	P1065R2	10	12	19.28 (16.8)*
Atomic waiting and notifying, std::counting_semaphore, std::latch and std::barrier	P1135R6	11	11	19.28 (16.8)*
std::source_location	P1208R6	11		19.29 (16.10)*
Adding <=> to the standard library	P1614R2	10	14	19.29 (16.10)*
constexpr default constructor of std::atomic and std::atomic_flag	P0883R2	10	13	19.26*
constexpr for numeric algorithms	P1645R1	10	12	19.26*
Safe integral comparisons	P0586R2	10	13	19.27*
C++20 feature	Paper(s)	GCC libstdc++	Clang libc++	MSVC STL	Apple Clang	Sun/Oracle C++ Standard Library	Embarcadero C++ Builder Standard Library	Cray C++ Standard Library

* - hover over the version number to see notes

• Working C++20 examples