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C++ standard libraries extensions

From cppreference.com

The C++ Extensions for Library Fundamentals, ISO/IEC TS 19568:2015 defines the following new components for the C++ standard library:

Contents

[edit] Not merged into C++17

The following components of ISO/IEC TS 19568:2015 were not selected for inclusion in C++17

[edit] Modified versions of existing classes to support type-erased allocators

Defined in header <experimental/functional>
a modified version of std::function with support for type-erased allocators
(class template)
Defined in header <experimental/future>
a modified version of std::promise with support for type-erased allocators
(class template)
a modified version of std::packaged_task with support for type-erased allocators
(class template)

[edit] Polymorphic allocators and memory resources

adapts an allocator into a memory_resource
(alias template)

Note: According to LWG issue 2700. the omission of resource_adaptor from C++17 merge may have been accidental.

[edit] General utilities

Defined in header <experimental/utility>
placeholder type for type erasure, such as in allocators
(class)
Defined in header <experimental/type_traits>
deduce the implied function type of the callable object when called with the given argument types
(class template)

[edit] Merged into C++17

The following components of ISO/IEC TS 19568:2015 were included into C++17

[edit] optional objects

Defined in header <experimental/optional>
a class template representing optional objects
(class template)

[edit] class any

Defined in header <experimental/any>
a type-safe container for single values of any type
(class)

[edit] string_view

Defined in header <experimental/string_view>
a non-owning reference to a string
(class template)

[edit] Type-erased and polymorphic allocators

[edit] Polymorphic allocators and memory resources

The entities in this section are declared in the std::experimental::pmr namespace.

Defined in header <experimental/memory_resource>
an abstract interface for classes that encapsulate memory resources
(class)
a thread-safe memory_resource for managing allocations in pools of different block sizes
(class) [edit]
a thread-unsafe memory_resource for managing allocations in pools of different block sizes
(class) [edit]
a special-purpose memory_resource that releases the allocated memory only when the resource is destroyed
(class)
an allocator that supports run-time polymorphism based on the memory_resource it is constructed with
(class template)
returns a static program-wide memory_resource that uses the global operator new and operator delete to allocate and deallocate memory
(function) [edit]
returns a static memory_resource that performs no allocation
(function) [edit]
gets the default memory_resource
(function) [edit]
sets the default memory_resource
(function) [edit]

[edit] Convenience aliases for containers using polymorphic allocators

Convenience aliases and alias templates for containers using polymorphic allocators are provided in the std::experimental::pmr namespace for the following class templates in the standard library:

List of container templates for which convenience aliases are provided

[edit] Array support for shared_ptr

Defined in header <experimental/memory>
Class Description
A modified version of std::shared_ptr that supports arrays
(class template)
A modified version of std::weak_ptr that supports arrays
(class template)

[edit] Sampling and searching algorithms

Defined in header <experimental/algorithm>
selects n random elements from a sequence
(function template)
applies a Searcher to a sequence
(function template)
Defined in header <experimental/functional>
standard C++ library search algorithm implementation
(class template)
helper function to create a default_searcher
(function template)
Boyer-Moore search algorithm implementation
(class template)
helper function to create a boyer_moore_searcher
(function template)
Boyer-Moore-Horspool search algorithm implementation
(class template)
helper function to create a boyer_moore_horspool_searcher
(function template)

[edit] General utilities

Defined in header <experimental/tuple>
calls a function to a tuple of arguments
(function template)

In addition, the TS provides numerous constexpr variable templates for the following type traits and other class templates in the standard library:

List of type traits and other class templates for which variable templates are provided

[edit] Feature test macros

Defined in header <experimental/optional>
__cpp_lib_experimental_optional
a value of at least 201411 indicates that the optional type is supported
(macro constant)
Defined in header <experimental/any>
__cpp_lib_experimental_any
a value of at least 201411 indicates that the any type is supported
(macro constant)
Defined in header <experimental/string_view>
__cpp_lib_experimental_string_view
a value of at least 201411 indicates that basic_string_view template is supported
(macro constant)
Defined in header <experimental/tuple>
__cpp_lib_experimental_apply
a value of at least 201402 indicates that the tuple apply() function is supported
(macro constant)
Defined in header <experimental/type_traits>
__cpp_lib_experimental_type_trait_variable_templates
a value of at least 201402 indicates that variable template type traits are supported
(macro constant)
__cpp_lib_experimental_invocation_type
a value of at least 201406 indicates that invocation type traits are supported
(macro constant)
Defined in header <experimental/functional>
__cpp_lib_experimental_boyer_moore_searching
a value of at least 201411 indicates that additional searching algorithms are supported
(macro constant)
__cpp_lib_experimental_function_erased_allocator
a value of at least 201406 indicates that type-erased allocator for std::function is supported
(macro constant)
Defined in header <experimental/future>
__cpp_lib_experimental_promise_erased_allocator
a value of at least 201406 indicates that type-erased allocator for std::promise is supported
(macro constant)
__cpp_lib_experimental_packaged_task_erased_allocator
a value of at least 201406 indicates that type-erased allocator for std::packaged_task is supported
(macro constant)
Defined in header <experimental/memory>
__cpp_lib_experimental_shared_ptr_arrays
a value of at least 201406 indicates that shared_ptr arrays are supported
(macro constant)
Defined in header <experimental/memory_resource>
__cpp_lib_experimental_memory_resources
a value of at least 201402 indicates that polymorphic memory resources are supported
(macro constant)
Defined in header <experimental/algorithm>
__cpp_lib_experimental_sample
a value of 201402 indicates that the sample algorithm is supported
(macro constant)