C++ standard libraries extensions, version 3

 

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)

Metaprogramming library (C++11)

Diagnostics library

General 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)

Concurrency support library (C++11)

Execution support library (C++26)

Technical specifications

Symbols index

External libraries

 

Experimental

Technical Specification

Filesystem library (filesystem TS)

Library fundamentals (library fundamentals TS)

Library fundamentals 2 (library fundamentals TS v2)

Library fundamentals 3 (library fundamentals TS v3)

Extensions for parallelism (parallelism TS)

Extensions for parallelism 2 (parallelism TS v2)

Extensions for concurrency (concurrency TS)

Extensions for concurrency 2 (concurrency TS v2)

Concepts (concepts TS)

Ranges (ranges TS)

Reflection (reflection TS)

Mathematical special functions (special functions TR)

Experimental Non-TS

Pattern Matching

Linear Algebra

std::execution

Contracts

2D Graphics

 

Library fundamentals v3

experimental::scope_exit

experimental::scope_fail

experimental::scope_success

experimental::unique_resource

 

Version 3 of the C++ Extensions for Library Fundamentals, ISO/IEC TS 19568:2024, defines the following new components for the C++ standard library, in addition to those defined in version 1 and version 2.

Components merged into C++17/20 and the following components are removed in LFTS v3:

• std::experimental::make_array,
• std::experimental::erased_type,
• std::experimental::packaged_task, and
• std::experimental::promise.

Scope guard

Defined in header <experimental/scope>
scope_exit	wraps a function object and invokes it on exiting the scope (class template)
scope_fail	wraps a function object and invokes it on exiting the scope through an exception (class template)
scope_success	wraps a function object and invokes it on exiting the scope normally (class template)
unique_resource	universal RAII resource handle wrapper (class template)

Feature test macros

Defined in header <experimental/memory_resource>
__cpp_lib_experimental_memory_resources	a value of at least 201803 indicates that resource_adaptor is supported (macro constant)
Defined in header <experimental/functional>
__cpp_lib_experimental_function_polymorphic_allocator	a value of at least 202211 indicates that std::pmr::polymorphic_allocator<> is used for std::experimental::function (macro constant)
Defined in header <experimental/scope>
__cpp_lib_experimental_scope	a value of at least 201902 indicates that the scope guards are supported (macro constant)

Notes

The value of __cpp_lib_experimental_memory_resources has been increased in LFTS v3, because the design of resource_adaptor is rebased onto std::pmr::memory_resource.