C++17

 

C++

Language

Standard Library Headers

Freestanding and hosted implementations

Named requirements

Language support library

Concepts library (C++20)

Diagnostics library

Utilities library

Strings library

Containers library

Iterators library

Ranges library (C++20)

Algorithms library

Numerics library

Localizations library

Input/output library

Filesystem library (C++17)

Regular expressions library (C++11)

Atomic operations library (C++11)

Thread support library (C++11)

Technical Specifications

 

Versions

C++98

C++03

C++11

C++14

C++17

C++20

Current Status

 

Following features were merged into C++17:

1. From TS's: the filesystem library, the library fundamentals v1 (including optional, any, string_view, polymorphic allocators, searchers, apply), parallelism v1 (including execution policies, reduce, inclusive_scan, exclusive_scan), but removing exception_list. From special function IS: mathematical special functions, from library fundamentals v2: std::gcd, std::lcm
2. From C11: std::aligned_alloc, std::timespec_get

Obsolete

Removed

auto_ptr, deprecated function objects, std::random_shuffle, std::unexpected, the obsolete iostreams aliases, trigraphs, the register keyword, bool increment

Deprecated

std::iterator, std::raw_storage_iterator, std::get_temporary_buffer, std::is_literal_type, std::result_of, all of <codecvt>

New language features

• fold-expressions
• class template argument deduction
• non-type template parameters declared with auto
• compile-time if constexpr
• inline variables
• structured bindings
• initializers for if and switch
• u8 character literal
• simplified nested namespaces
• using-declaration declaring multiple names
• made noexcept part of type system
• new order of evaluation rules

• guaranteed copy elision
• lambda capture of *this
• constexpr lambda
• attribute namespaces don't have to repeat
• new attributes:
  • [[fallthrough]]
  • [[nodiscard]]
  • [[maybe_unused]]
• __has_include

New headers

• <any>
• <optional>
• <variant>
• <memory_resource>
• <string_view>
• <charconv>
• <execution>
• <filesystem>

New library features

Utility types

• tuple:
  • apply
  • deduction_guides
  • make_from_tuple
• variant
• as_const
• searchers
• optional
• any
• not_fn

Memory management

• uninitialized memory algorithms
  • destroy_at
  • destroy
  • destroy_n
  • uninitialized_move
  • uninitialized_value_construct

• weak_from_this
• memory_resource and polymorphic_allocator
• aligned_alloc
• transparent owner_less
• array support for shared_ptr
• allocation functions with explicit alignment

Compile-time programming

• byte
• conjunction/disjunction/negation
• type trait variable templates (xxx_v)
• is_swappable
• is_invocable
• is_aggregate
• has_unique_object_representations

Algorithms

• clamp
• parallel algorithms and execution policies
• reduce
• inclusive_scan
• exclusive_scan
• gcd
• lcm

Iterators and containers

• map/set extract and map/set merge
• map/unordered_map try_emplace and insert_or_assign
• contiguous iterators
• non-member size/empty/data

Numerics

• mathematical special functions
• 3D hypot

Other

• launder
• to_chars/from_chars
• is_always_lock_free
• scoped_lock
• cache line interface
• uncaught_exceptions
• timespec_get
• rounding functions for duration and time_point

Compiler support

Main Article: C++ compiler support

C++17 core language features

C++17 feature	Paper(s)	GCC	Clang	MSVC	Apple Clang	EDG eccp	Intel C++	IBM XLC++	Sun/Oracle C++	Embarcadero C++ Builder	Cray	Portland Group (PGI)	Nvidia nvcc
New auto rules for direct-list-initialization	N3922	5	3.8	19.0*	Yes	4.10.1	17.0			10.3		17.7
static_assert with no message	N3928	6	2.5	19.10*	Yes	4.12	18.0			10.3		17.7	11.0
typename in a template template parameter	N4051	5	3.5	19.0*	Yes	4.10.1	17.0			10.3		17.7
Removing trigraphs	N4086	5	3.5	16.0*	Yes	5.0				10.3		19.1
Nested namespace definition	N4230	6	3.6	19.0*	Yes	4.12	17.0			10.3		17.7
Attributes for namespaces and enumerators	N4266	4.9 (partial)* 6	3.6	19.0*	Yes	4.11	17.0			10.3		17.7
u8 character literals	N4267	6	3.6	19.0*	Yes	4.11	17.0			10.3		17.7
Allow constant evaluation for all non-type template arguments	N4268	6	3.6	19.12*	Yes	5.0	19.0.1			10.3		19.1
Fold Expressions	N4295	6	3.6	19.12*	Yes	4.14	19.0			10.3		18.1
Unary fold expressions and empty parameter packs	P0036R0	6	3.9	19.12*	Yes	4.14				10.3		19.1
Remove Deprecated Use of the register Keyword	P0001R1	7	3.8	19.11*	Yes	4.13	18.0			10.3		17.7
Remove Deprecated operator++(bool)	P0002R1	7	3.8	19.11*	Yes	4.13	18.0			10.3		17.7
Make exception specifications part of the type system	P0012R1	7	4	19.12*	Yes	4.14	19.0			10.3		19.1
Aggregate initialization of classes with base classes	P0017R1	7	3.9	19.14*	Yes	5.0	19.0.1			10.3		19.1
__has_include in preprocessor conditionals	P0061R1	5	Yes	19.11*	Yes	4.13	18.0			10.3		17.7
DR: New specification for inheriting constructors (DR1941 et al)	P0136R1	7	3.9	19.14*	Yes	6.1				10.3		19.1
Lambda capture of *this	P0018R3	7	3.9	19.11*	Yes	4.14	19.0			10.3		18.1
Direct-list-initialization of enumerations	P0138R2	7	3.9	19.11*	Yes	4.14	18.0			10.3		19.1
constexpr lambda expressions	P0170R1	7	5	19.11*	Yes	4.14	19.0			10.3		18.1
Differing begin and end types in range-based for	P0184R0	6	3.9	19.10*	Yes	4.12	18.0			10.3		17.7
[[fallthrough]] attribute	P0188R1	7	3.9	19.10*	Yes	4.13	18.0			10.3		17.7
[[nodiscard]] attribute	P0189R1	7	3.9	19.11*	Yes	4.13	18.0			10.3		17.7
[[maybe_unused]] attribute	P0212R1	7	3.9	19.11*	Yes	4.13	18.0			10.3		17.7
Hexadecimal floating-point literals	P0245R1	3.0	Yes	19.11*	Yes	4.13	18.0			10.3		17.7
Using attribute namespaces without repetition	P0028R4	7	3.9	19.11*	Yes	4.13	18.0			10.3		17.7
Dynamic memory allocation for over-aligned data	P0035R4	7	4	19.12*	10.0.0*	4.14	19.0			10.3		19.1
Class template argument deduction	P0091R3	7	5	19.14*	Yes	5.0	19.0.1			10.3		19.1
Non-type template parameters with auto type	P0127R2	7	4	19.14*	Yes	5.0	19.0.1			10.3		19.1
Guaranteed copy elision	P0135R1	7	4	19.13*	Yes	5.0	19.0.1			10.3		19.1
Replacement of class objects containing reference members	P0137R1	7	6	19.14*	Yes	5.0				10.3		19.1
Stricter expression evaluation order	P0145R3	7	4	19.14*	Yes	5.0	19.0.1			10.3		19.1
Structured Bindings	P0217R3	7	4	19.11*	Yes	4.14	19.0			10.3		18.1	11.0*
Ignore unknown attributes	P0283R2	Yes	3.9	19.11*	Yes	4.13	18.0			10.3		17.7
constexpr if statements	P0292R2	7	3.9	19.11*	Yes	4.14	19.0			10.3		18.1	11.0
init-statements for if and switch	P0305R1	7	3.9	19.11*	Yes	4.14	18.0			10.3		18.1
Inline variables	P0386R2	7	3.9	19.12*	Yes	4.14	19.0			10.3		18.1	11.0
Removing dynamic exception specifications	P0003R5	7	4	19.10*	Yes	4.14	19.0			10.3		19.1
Pack expansions in using-declarations	P0195R2	7	4	19.14*	Yes	5.0	19.0			10.3		19.1
DR: Matching of template template-arguments excludes compatible templates	P0522R0	7	4	19.12*	Yes	5.0	19.0.1			10.3		19.1
C++17 feature	Paper(s)	GCC	Clang	MSVC	Apple Clang	EDG eccp	Intel C++	IBM XLC++	Sun/Oracle C++	Embarcadero C++ Builder	Cray	Portland Group (PGI)	Nvidia nvcc

C++17 library features

C++17 feature	Paper(s)	GCC libstdc++	Clang libc++	MSVC Standard Library	Apple Clang	Intel Parallel STL	Sun/Oracle C++ Standard Library	Embarcadero C++ Builder Standard Library	Cray C++ Standard Library
std::void_t	N3911	6	3.6	19.0*	Yes	N/A		10.3
std::uncaught_exceptions()	N4259	6	3.7	19.0*	Yes	N/A
std::size(), std::empty() and std::data()	N4280	6	3.6	19.0*	Yes	N/A		10.3
Improving std::pair and std::tuple	N4387	6	4	19.0*	Yes	N/A		10.3
std::bool_constant	N4389	6	3.7	19.0*	Yes	N/A		10.3
std::shared_mutex (untimed)	N4508	6	3.7	19.0*	Yes	N/A		10.3
Type traits variable templates	P0006R0	7	3.8	19.0*	Yes	N/A		10.3
Logical operator type traits	P0013R1	6	3.8	19.0*	Yes	N/A		10.3
Standardization of Parallelism TS	P0024R2	9*		19.14*		18.0*
std::clamp()	P0025R0	7	3.9	19.0*	10.0.0*	N/A		10.3
Hardware interference size	P0154R1			19.11*		N/A
(nothrow-)swappable traits	P0185R1	7	3.9	19.0*	10.0.0*	N/A		10.3
File system library	P0218R1	8 (partial)*	7	19.14*	11.0.0*	N/A		10.3
std::string_view	N3921 P0220R1	7	4	19.10*	10.0.0*	N/A		10.3
std::any	P0220R1	7	4	19.10*	10.0.0*	N/A		10.3
std::optional	P0220R1	7	4	19.10*	10.0.0*	N/A		10.3
Polymorphic memory resources	P0220R1	9		19.13*		N/A		10.3
Mathematical special functions	P0226R1	7		19.14*		N/A		10.3
C++17 should refer to C11 instead of C99	P0063R3	9	7	19.0* (partial)*	10.0.0*	N/A
Splicing Maps and Sets	P0083R3	7	8	19.12*	10.0.0*	N/A
std::variant	P0088R3	7	4	19.10*	10.0.0*	N/A		10.3
std::make_from_tuple()	P0209R2	7	3.9	19.10*	Yes	N/A		10.3
std::has_unique_object_representations	P0258R2	7	6	19.11*	Yes	N/A		10.3
std::gcd() and std::lcm()	P0295R0	7	4	19.11*	Yes	N/A		10.3
std::not_fn	P0005R4 P0358R1	7	3.9	19.12*	Yes	N/A		10.3
Elementary string conversions	P0067R5	8 (no FP) 11	7 (no FP)	19.14* (no FP)* 19.24*	10.0.0* (no FP)	N/A
std::shared_ptr and std::weak_ptr with array support	P0414R2	7	11	19.12*		N/A		10.3
std::scoped_lock	P0156R2	7	5	19.11*	Yes	N/A		10.3
std::byte	P0298R3	7	5	19.11*	Yes	N/A		10.3
std::is_aggregate	LWG2911	7	5	19.15*	Yes	N/A		10.3
C++17 feature	Paper(s)	GCC libstdc++	Clang libc++	MSVC Standard Library	Apple Clang	Intel Parallel STL	Sun/Oracle C++ Standard Library	Embarcadero C++ Builder Standard Library	Cray C++ Standard Library

* - hover over the version number to see notes

• Working c++17 examples