Compiler support for C++20

 

C++

Compiler support

Freestanding and hosted

Language

Standard library

Standard library headers

Named requirements

Feature test macros(C++20)

Language support library

Concepts library(C++20)

Diagnostics library

Memory management library

Metaprogramming library(C++11)

General utilities library

Containers library

Iterators library

Ranges library(C++20)

Algorithms library

Strings library

Text processing library

Numerics library

Date and time library

Input/output library

Filesystem library(C++17)

Concurrency support library(C++11)

Execution control library(C++26)

Technical specifications

Symbols index

External libraries

 

Compiler support

C++11

C++14

C++17

C++20

C++23

C++26

 

* - 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.

C++20 core language features

C++20 feature	Paper(s)	GCC	Clang	MSVC	Apple Clang	EDG eccp	Intel C++	Nvidia HPC C++ (ex PGI)*	Nvidia nvcc	Cray
Allow Lambda capture[=, this]	P0409R2	8	6	19.22*	10.0.0*	5.1	2021.1	20.7	12.0	11.0
__VA_OPT__	P0306R4 P1042R1	8 (partial)* 10 (partial)* 12	9	19.25*	11.0.3*	5.1	2021.1	20.7	12.0	11.0
Designated initializers  (FTM)*	P0329R4	4.7 (partial)* 8	3.0 (partial)* 10	19.21*	12.0.0*	5.1	2021.1	20.7	12.0	11.0
template-parameter-list for generic lambdas  (FTM)*	P0428R2	8	9	19.22*	11.0.0*	5.1	2021.1	20.7	12.0	11.0
Default member initializers for bit-fields	P0683R1	8	6	19.25*	10.0.0*	5.1	2021.1	20.7	12.0	11.0
Initializer list constructors in class template argument deduction	P0702R1	8	6	19.14*	Yes	5.0	2021.1	20.7	12.0	11.0
const&-qualified pointers to members	P0704R1	8	6	19.0 (2015)*	10.0.0*	5.1	2021.1	20.7	12.0	11.0
Concepts  (FTM)*	P0734R0	5* 10	10	19.23*(partial)* 19.30*	12.0.0* (partial)	6.1	2023.1*	20.11	12.0	11.0
Lambdas in unevaluated contexts	P0315R4	9	13 (partial)* 14 (partial)* 17	19.28 (16.8)*	13.1.6* (partial)	6.2	2023.1 (partial) 2024.0	20.7	12.0
Three-way comparison operator  (FTM)*	P0515R3	10	8 (partial) 10	19.20*	12.0.0*	5.1	2021.1	20.7	12.0	11.0
DR11: Simplifying implicit lambda capture	P0588R1	8		19.24*		5.1	2021.1	20.7	12.0
init-statements for range-based for	P0614R1	9	8	19.25*	11.0.0*	6.0	2021.7	20.11	12.0	11.0
Default constructible and assignable stateless lambdas	P0624R2	9	8	19.22*	10.0.1*	5.1	2021.1	20.7	12.0	11.0
Type mismatch of defaulted special member functions	P0641R2	9 (partial)*	8	19.0 (2015)*(partial)*	10.0.1*	5.1	2021.1	20.7	12.0	11.0
Access checking on specializations	P0692R1	Yes	8 (partial) 14	19.26*	14.0.0*	5.1	2021.1	20.7	12.0
ADL and function templates that are not visible	P0846R0	9	9	19.21*	11.0.3*	5.1	2021.1	20.7	12.0	11.0
DR11: Specify when constexpr function definitions are needed for constant evaluation  (FTM)*	P0859R0	5.2 (partial)* 9	8	19.27* (partial)* 19.31**	11.0.0*	(partial)			12.0	11.0
Attributes [[likely]] and [[unlikely]]	P0479R5	9	12	19.26*	13.0.0*	5.1	2021.7	20.7	12.0
Make typename more optional	P0634R3	9	16	19.29 (16.10)*	16.0.0*	5.1	2023.1	20.7	12.0
Pack-expansions in lambda init-captures  (FTM)*	P0780R2	9	9	19.22*	11.0.3*	6.1	2021.7	20.11	12.0	11.0
Attribute [[no_unique_address]]	P0840R2	9	9	19.28 (16.9)**	11.0.3*	5.1	2021.1	20.7	12.0	11.0
Conditionally trivial special member functions  (FTM)*	P0848R3	10	16	19.28 (16.8)*		6.1	2021.7	20.11	12.0
DR17: Relaxing the structured bindings customization point finding rules	P0961R1	8	8	19.20*	10.0.1*	5.1	2021.1	20.7	12.0	11.0
DR11: Relaxing the range-for loop customization point finding rules	P0962R1	8	8	19.25*	11.0.0*	5.1	2021.1	20.7	12.0	11.0
DR17: Allow structured bindings to accessible members	P0969R0	8	8	19.20*	10.0.1*	5.1	2021.1	20.7	12.0	11.0
Destroying operator delete  (FTM)*	P0722R3	9	6	19.27*	10.0.0*	6.1	2023.1	20.11	12.0	11.0
Class types in Constant template parameters	P0732R2	9	12 (partial)	19.26*(partial)* 19.28 (16.9)*	13.0.0* (partial)	6.2	2023.1 (partial)	21.3	12.0
Deprecate implicit capture of this via [=]	P0806R2	9	7	19.22*	10.0.1*	5.1		20.7	12.0	11.0
explicit(bool)  (FTM)*	P0892R2	9	9	19.24*	11.0.3*	5.1	2021.1	20.7	12.0	11.0
Integrating feature-test macros	P0941R2	5	3.4	19.15* (partial) 19.20*	Yes	5.0	2021.1	20.7	12.0	11.0
Prohibit aggregates with user-declared constructors	P1008R1	9	8	19.20*	10.0.1*	5.1	2021.1	20.7	12.0	11.0
constexprvirtual function  (FTM)*	P1064R0	9	9	19.28 (16.9)*	11.0.3*	5.1	2021.1	20.7	12.0	11.0
Consistency improvements for comparisons	P1120R0	10	8 (partial) 10	19.22*	12.0.0*	5.1	2023.1	20.7	12.0	11.0
char8_t  (FTM)*	P0482R6	9	7*	19.22*	10.0.0*	5.1	2021.1	20.7	12.0	11.0
std::is_constant_evaluated()  (FTM)*	P0595R2	9	9	19.25*	11.0.3*	5.1	19.1	21.1	12.0	11.0
constexprtry-catch blocks	P1002R1	9	8	19.25*	10.0.1*	5.1	2023.1	20.7	12.0	11.0
Immediate functions (consteval)  (FTM)*	P1073R3	10 (partial)* 11	11 (partial) 14 (partial)* 17	19.28 (16.8)* (partial)* 19.29 (16.10)*	11.0.3* (partial) 15.0.0*	5.1	2021.1	20.7	12.0
Nested inline namespaces	P1094R2	9	8	19.27*	10.0.1*	5.1	2021.1	20.7	12.0	11.0
Yet another approach for constraineddeclarations	P1141R2	10	10	19.26* (partial) 19.28 (16.9)*	12.0.5*	6.1	2023.1	20.11	12.0	11.0
Signed integers are two's complement	P1236R1	9	9	Yes	11.0.3*	N/A	2023.1*	yes*	12.0	11.0
dynamic_cast and polymorphic typeid in constant expressions	P1327R1	10	9	19.28 (16.9)*	11.0.3*	5.1	2021.1	20.7	12.0	11.0
Changing the active member of a union inside constexpr  (FTM)*	P1330R0	9	9	19.10*	11.0.3*	5.1	2021.1	20.7	12.0	11.0
Coroutines  (FTM)*  (FTM)*	P0912R5 LWG3393	10	8 (partial) 17 (partial)*	19.0 (2015)* (partial) 19.10** 19.28 (16.8)*	10.0.1* (partial)	5.1	2021.1	23.3*	12.0 (host code only)
Parenthesized initialization of aggregates  (FTM)*	P0960R3	10	16	19.28 (16.8)*	16.0.0*	5.1	2021.1	20.7	12.0
DR11: Array size deduction in new-expressions	P1009R2	11	9	19.27*	11.0.3*	5.1	2021.1	20.7	12.0	11.0
Modules  (FTM)*	P1103R3	11 (partial)	8 (partial)	19.0 (2015)* (partial) 19.10** 19.28 (16.8)*	10.0.1* (partial)		2023.1 (partial)
Stronger Unicode requirements	P1041R4 P1139R2	10	Yes	19.0 (2015)** 19.26**	Yes	N/A	2023.1*	Yes	12.0	11.0
<=> != ==	P1185R2	10	10	19.22*	12.0.0*	5.1	2021.1	20.7	12.0	11.0
DR11: Explicitly defaulted functions with different exception specifications	P1286R2	10	9	19.28 (16.8)*	11.0.3*	5.1	2021.1	20.7	12.0	11.0
Lambda capture and storage class specifiers of structured bindings	P1091R3 P1381R1	10	8 (partial) 16	19.11** 19.24**	16.0.0*	5.1	2021.1	20.7	12.0
Permit conversions to arrays of unknown bound	P0388R4	10	14	19.27*	14.0.0*	6.0	2021.5	20.11	12.0
constexpr container operations  (FTM)*	P0784R7	10	10	19.28 (16.9)*	12.0.0*	6.0	2021.5	20.11	12.0	11.0
Deprecating some uses of volatile	P1152R4	10	10	19.27*	12.0.0*	6.0	2021.5	20.11	12.0	11.0
constinit  (FTM)*	P1143R2	10	10	19.29 (16.10)*	12.0.0*	6.1	2021.7	20.11	12.0	11.0
Deprecate comma operator in subscripts	P1161R3	10	9	19.25*	11.0.3*	6.0	2021.7	20.11	12.0	11.0
[[nodiscard]] with message	P1301R4	10	9	19.25*	11.0.3*	6.0	2021.5	20.11	12.0	11.0
Trivial default initialization in constexpr functions	P1331R2	10	10	19.27*	12.0.0*	6.1	2021.7	20.11	12.0	11.0
Unevaluated asm-declaration in constexpr functions	P1668R1	10	10	19.28 (16.9)*	12.0.0*	6.1	2021.7	20.11	12.0	11.0
using enum  (FTM)*	P1099R5	11	13	19.24*	13.1.6*	6.3	2023.1	22.5	12.0
Synthesizing Three-way comparison for specified comparison category	P1186R3	11	10	19.24*	12.0.0*	6.0	2021.5	20.11	12.0	11.0
DR17: [[nodiscard]] for constructors	P1771R1	10	9	19.24*	11.0.3*	6.0	2021.5	20.11	12.0	11.0
class template argument deduction for alias templates  (FTM)*	P1814R0	10	19	19.27*		6.5		23.9	12.0
class template argument deduction for aggregates  (FTM)*	P1816R0 P2082R1	10* 11*	17	19.27*		6.3	2023.1 (partial)* 2024.1	23.3	12.0
DR11: Implicit move for more local objects and rvalue references	P1825R0	11*	13	19.24*	13.1.6*	6.0	2021.5	20.11	12.0
Allow defaulting comparisons by value	P1946R0	10	10	19.25*	12.0.0*	6.1	2021.7	20.11	12.0	11.0
Remove std::weak_equality and std::strong_equality	P1959R0	10	10	19.25*	12.0.0*	6.1	2021.7	20.11	12.0	11.0
Inconsistencies with constant template parameters  (FTM)*	P1907R1	10 (partial) 11	18 (partial)*	19.26*	13.1.6* (partial)	6.2	2023.1 (partial)	21.3	12.0
DR98: Pseudo-destructors end object lifetimes	P0593R6	11	11	Yes	12.0.5*	N/A	2023.1*	Yes	12.0	11.0
DR11: Converting from T* to bool should be considered narrowing	P1957R2	10* 11*	11	19.27*	12.0.5*	6.1			12.0	11.0
C++20 feature	Paper(s)	GCC	Clang	MSVC	Apple Clang	EDG eccp	Intel C++	Nvidia HPC C++ (ex PGI)*	Nvidia nvcc	Cray

C++20 library features

C++20 feature	Paper(s)	GCC libstdc++	Clang libc++	MSVC STL	Apple Clang*
std::endian  (FTM)*	P0463R1	8	7	19.22*	10.0.0*
Extending std::make_shared() to support arrays  (FTM)*	P0674R1	12	15	19.27*	14.0.3*
Floating-point atomic  (FTM)*	P0020R6	10	18	19.22*	16.0.0*
Synchronized buffered (std::basic_osyncstream)  (FTM)*	P0053R7	11	18	19.29 (16.10)*
constexpr for <algorithm> and <utility>  (FTM)*	P0202R3	10	8 (partial) 12	19.26*	10.0.1* (partial) 13.0.0*
More constexpr for <complex>  (FTM)*	P0415R1	9	7 (partial) 16	19.27*	10.0.0* (partial) 15.0.0*
Make std::memory_order a scoped enumeration	P0439R0	9	9	19.25*	11.0.3*
Stringprefix and suffix checking: string(_view) ::starts_with / ends_with  (FTM)*	P0457R2	9	6	19.21*	10.0.0*
Library support for operator<=><compare>  (FTM)*	P0768R1	10	7 (partial) 12 (partial)* 17	19.20* (partial) 19.28 (16.9)*	13.0.0*
std::remove_cvref  (FTM)*	P0550R2	9	6	19.20*	10.0.0*
[[nodiscard]] in the standard library	P0600R1	9	7 (partial) 16	19.13* (partial) 19.22*	10.0.0* (partial) 15.0.0*
Using std::move in numeric algorithms	P0616R0	9	12	19.23*	13.0.0*
Utility to convert a pointer to a raw pointer  (FTM)*	P0653R2	8	6	19.22*	Yes
Atomic std::shared_ptr and std::weak_ptr  (FTM)*	P0718R2	12		19.27*
std::span  (FTM)*	P0122R7	10	7	19.26*	10.0.0*
Calendar and Time zone  (FTM)*	P0355R7	11 (partial)* 13 (partial)* 14	7 (partial) 19 (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  (FTM)*  (FTM)*	P0858R0	9	12	19.11*	13.0.0*
std::basic_string::reserve() should not shrink	P0966R1	11	8	19.25*	10.0.1*
Atomic Compare-And-Exchange with padding bits	P0528R3	13		19.28 (16.8)*
std::atomic_ref  (FTM)*	P0019R8	10	19	19.28 (16.8)*
contains() member function of associative containers, e.g. std::map::contains()	P0458R2	9	13	19.21*	13.1.6*
DR11: Guaranteed copy elision for piecewise construction	P0475R1	9	Yes	19.29 (16.10)*	Yes
std::bit_cast()  (FTM)*	P0476R2	11	14	19.27*	14.0.3*
Integral power-of-2 operations: std::bit_ceil(), std::bit_floor(), std::bit_width(), std::has_single_bit()  (FTM)*	P0556R3 P1956R1	9* 10*	9* 12*	19.25** 19.27** 19.28 (16.8)*	11.0.3** 13.0.0**
Improving the return value of erase-like algorithms  (FTM)*	P0646R1	9	10	19.21*	12.0.0*
std::destroying_delete_t  (FTM)*	P0722R3	9	9	19.27*	11.0.3*
std::is_convertible  (FTM)*	P0758R1	9	9	19.23*	11.0.3*
Add std::shift_left/right to <algorithm>  (FTM)*	P0769R2	10	12	19.21*	13.0.0*
Constexpr for std::swap() and swap related functions	P0879R0	10	13	19.26*	13.1.6*
std::type_identity  (FTM)*	P0887R1	9	8	19.21*	10.0.1*
Concepts library  (FTM)*	P0898R3	10	13	19.23*	13.1.6*
constexprcomparison operators for std::array	P1023R0	10	8	19.27*	10.0.1*
std::unwrap_ref_decay and std::unwrap_reference  (FTM)*	P0318R1	9	8	19.21*	10.0.1*
std::bind_front()  (FTM)*	P0356R5	9	13	19.25*	13.1.6*
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  (FTM)*	P0482R6	9	8 (partial) 16	19.22*	10.0.1* (partial) 15.0.0*
Utility functions to implement uses-allocatorconstruction	P0591R4	9	16	19.29 (16.10)*	15.0.0*
DR17: std::variant and std::optional should propagate copy/move triviality	P0602R4	8.3	8	19.11*	10.0.1*
DR17: A sane std::variant converting constructor	P0608R3	10	9	19.29 (16.10)** 19.42**	11.0.3*
std::function's move constructor should be noexcept	P0771R1	7.2	6	19.22*	Yes
The OneRangesProposal  (FTM)*	P0896R4	10	13 (partial) 15*	19.29 (16.10)*	14.0.3*
Heterogeneous lookup for unordered associative containers  (FTM)*	P0919R3 P1690R1	11	12	19.23* (P0919R3) 19.25* (P1690R1)	13.0.0*
<chrono>zero(), min(), and max() should be noexcept	P0972R0	9	8	19.14*	10.0.1*
constexpr in std::pointer_traits  (FTM)*	P1006R1	9	8	19.26*	10.0.1*
std::assume_aligned()  (FTM)*	P1007R3	9* 11	15	19.28 (16.9)*	14.0.3*
Smart pointer creation with default initialization (e.g. make_unique_for_overwrite)  (FTM)*	P1020R1 P1973R1	11* 12*	16	19.28 (16.9)*	15.0.0*
Misc constexpr bits  (FTM)*  (FTM)*  (FTM)*  (FTM)*  (FTM)*  (FTM)*	P1032R1	10	13	19.28 (16.8)*	13.1.6*
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	15	19.26*	14.0.3*
Consistent container erasure, e.g. std::erase(std::vector), or std::erase_if(std::map)  (FTM)*	P1209R0 P1115R3	9* 10*	8* 11*	19.25** 19.27**	10.0.1** 12.0.5**
Standard library header units	P1502R1	11		19.29 (16.10)*
polymorphic_allocator<> as a vocabulary type  (FTM)*	P0339R6	9	16	19.28 (16.9)*	15.0.0*
std::execution::unseq  (FTM)*	P1001R2	9	17	19.28 (16.8)*
std::lerp() and std::midpoint()  (FTM)*	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*
DR17: Make std::create_directory() intuitive	P1164R1	8.3	12	19.20*	13.0.0*
std::ssize() and unsigned extent for std::span  (FTM)*	P1227R2	10	9	19.25*	11.0.3*
Traits for (un)bounded arrays  (FTM)*	P1357R1	9	9	19.25*	11.0.3*
std::to_array()  (FTM)*	P0325R4	10	10	19.25*	12.0.0*
Efficient access to std::basic_stringbuf’s buffer	P0408R7	11	17	19.29 (16.10)*	15.0.0*
Layout-compatibility and pointer-interconvertibility traits  (FTM)*  (FTM)*	P0466R5	12		19.29 (16.10)**
Bit operations: std:: rotl(), rotr(), countl_zero(), countl_one(), countr_zero(), countr_one(), popcount()  (FTM)*	P0553R4	9	9	19.25** 19.28 (16.8)*	11.0.3*
Mathematical constants  (FTM)*	P0631R8	10	11	19.25*	12.0.5*
Text formatting  (FTM)*	P0645R10	13	14** 17	19.29 (16.10)*	15.0.0*
std::stop_token and std::jthread  (FTM)*	P0660R10	10	17 (partial)* 20*	19.28 (16.9)*
constexprstd::allocator and related utilities  (FTM)*	P0784R7	10	12	19.29 (16.10)*	13.0.0*
constexprstd::string  (FTM)*	P0426R1 P1032R1 P0980R1	12	15	19.29 (16.10)* 19.30**	14.0.3*
constexprstd::vector  (FTM)*	P1004R2	12	15	19.29 (16.10)* 19.30**	14.0.3*
Input range adaptors	P1035R7	10	16	19.29 (16.10)*	15.0.0*
constexprstd::invoke() and related utilities	P1065R2	10	12	19.28 (16.8)*	13.0.0*
Atomic waiting and notifying, std::counting_semaphore, std::latch and std::barrier  (FTM)*  (FTM)*  (FTM)*  (FTM)*  (FTM)*  (FTM)*	P1135R6	11	11	19.28 (16.9)*	13.1.6*
std::source_location  (FTM)*	P1208R6	11	15* (partial) 16	19.29 (16.10)*	15.0.0*
Adding <=> to the standard library	P1614R2	10	14* (partial) 17* (partial) 19	19.29 (16.10)*	13.1.6* (partial)
constexpr default constructor of std::atomic and std::atomic_flag  (FTM)*	P0883R2	10	13	19.26*	13.1.6*
constexpr for numeric algorithms  (FTM)*	P1645R1	10	12	19.26*	13.0.0*
Safe integral comparisons  (FTM)*	P0586R2	10	13	19.27*	13.1.6*
C++20 feature	Paper(s)	GCC libstdc++	Clang libc++	MSVC STL	Apple Clang*