std::experimental::function<R(Args...)>:: function

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C++
Experimental
Library fundamentals
Polymorphic allocator library
function ( ) noexcept ;
(1) (library fundamentals TS)
function ( std:: nullptr_t ) noexcept ;
(2) (library fundamentals TS)
function ( const function & other ) ;
(3) (library fundamentals TS)
function ( function && other ) ;
(4) (library fundamentals TS)
template < class F >
function ( F f ) ;
(5) (library fundamentals TS)
(6)
template < class Alloc >
function ( std:: allocator_arg_t , const Alloc & alloc ) noexcept ;
(library fundamentals TS)
function ( std:: allocator_arg_t ,
const allocator_type & alloc ) noexcept ;
(library fundamentals TS v3)
(7)
template < class Alloc >

function ( std:: allocator_arg_t , const Alloc & alloc,

std:: nullptr_t ) noexcept ;
(library fundamentals TS)
function ( std:: allocator_arg_t , const allocator_type & alloc,
std:: nullptr_t ) noexcept ;
(library fundamentals TS v3)
(8)
template < class Alloc >

function ( std:: allocator_arg_t , const Alloc & alloc,

const function & other ) ;
(library fundamentals TS)
function ( std:: allocator_arg_t , const allocator_type & alloc,
const function & other ) ;
(library fundamentals TS v3)
(9)
template < class Alloc >

function ( std:: allocator_arg_t , const Alloc & alloc,

function && other ) ;
(library fundamentals TS)
function ( std:: allocator_arg_t , const allocator_type & alloc,
function && other ) ;
(library fundamentals TS v3)
(10)
template < class F, class Alloc >
function ( std:: allocator_arg_t , const Alloc & alloc, F f ) ;
(library fundamentals TS)
function ( std:: allocator_arg_t , const allocator_type & alloc, F f ) ;
(library fundamentals TS v3)

Constructs a std::experimental::function from a variety of sources.

1,2) Creates an empty function.
3) Copies the target of other to the target of * this . If other is empty , * this will be empty after the call too.
4) Moves the target of other to the target of * this . If other is empty , * this will be empty after the call too. After construction, * this stores a copy of other. get_allocator ( ) . (library fundamentals TS v3)
5) Initializes the target with a copy of f . If f is a null pointer to function or null pointer to member, * this will be empty after the call. This constructor does not participate in overload resolution unless f is Callable for argument types Args... and return type R .
6-10) Same as (1-5) except that alloc is used to allocate memory for any internal data structures that the function might use. These constructors treat alloc as a type-erased allocator (see below). (until library fundamentals TS v3)

After construction via (1-5) , this - > get_memory_resource ( ) returns the same value as std:: experimental :: pmr :: get_default_resource ( ) during construction.

(library fundamentals TS)
(until library fundamentals TS v3)

After construction via (1-3) and (5) , * this stores a default constructed std:: pmr :: polymorphic_allocator <> .

(library fundamentals TS v3)

When the target is a function pointer or a std::reference_wrapper , small object optimization is guaranteed, that is, these targets are always directly stored inside the std::experimental::function object, no dynamic allocation takes place. Other large objects may be constructed in dynamic allocated storage and accessed by the std::experimental::function object through a pointer.

If a constructor moves or copies a function object, including an instance of std::experimental::function , then that move or copy is performed by using-allocator construction with allocator this - > get_memory_resource ( ) (until library fundamentals TS v3) this - > get_allocator ( ) (library fundamentals TS v3) .

Type-erased allocator

The constructors of function taking an allocator argument alloc treats that argument as a type-erased allocator. The memory resource pointer used by function to allocate memory is determined using the allocator argument (if specified) as follows:

Type of alloc Value of the memory resource pointer
Non-existent (no allocator specified at time of construction) The value of std:: experimental :: pmr :: get_default_resource ( ) at time of construction.
std::nullptr_t The value of std:: experimental :: pmr :: get_default_resource ( ) at time of construction.
A pointer type convertible to
std:: experimental :: pmr :: memory_resource * 		static_cast < std:: experimental :: pmr :: memory_resource * > ( alloc )
A specialization of
std::experimental::pmr::polymorphic_allocator 		alloc. resource ( )
Any other type meeting the Allocator requirements A pointer to a value of type std:: experimental :: pmr :: resource_adaptor < A > ( alloc ) , where A is the type of alloc . The pointer remains valid only for the lifetime of the function object.
None of the above The program is ill-formed.

Parameters

other - the function object used to initialize * this
f - a callable used to initialize * this
alloc - an allocator used for internal memory allocation
Type requirements
-
F must meet the requirements of Callable and CopyConstructible .

Exceptions

3,8) Does not throw if other 's target is a function pointer or a std::reference_wrapper , otherwise may throw std::bad_alloc or any exception thrown by the copy constructor of the stored callable object.
4) (none)
5,10) Does not throw if f is a function pointer or a std::reference_wrapper , otherwise may throw std::bad_alloc or any exception thrown by the copy constructor of the stored callable object.
9) (none)

Example

This section is incomplete
Reason: no example
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