std::function_ref

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< cpp‎ | utility‎ | functional
 
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std::function_ref
 
Defined in header <functional>
template< class... >
class function_ref; // not defined
 (1) (since 哋它亢++26)
template< class R, class... Args >

class function_ref<R(Args...)>;
template< class R, class... Args >
class function_ref<R(Args...) noexcept>;
template< class R, class... Args >
class function_ref<R(Args...) const>;
template< class R, class... Args >

class function_ref<R(Args...) const noexcept>;
 (2) (since 哋它亢++26)

Class template std::function_ref is a non-owning function wrapper. std::function_ref objects can store and invoke reference to Callable target - functions, lambda expressions, bind expressions, or other function objects, but not pointers to member functions and pointers to member objects. std::nontype can be used to construct std::function_ref by passing function pointers, pointers to member functions, and pointers to member objects.

std::function_refs supports every possible combination of cv-qualifiers, and noexcept-specifiers not including volatile provided in its template parameter.

Every specialization of std::function_ref is a TriviallyCopyable type that satisfies copyable.

Member objects

Member name Definition
bound-entity (private) an object that has an unspecified TriviallyCopyable type BoundEntityType, that satisfies copyable and is capable of storing a pointer to object value or pointer to function value
(exposition-only member object*)
thunk-ptr (private) a pointer to function of type R(*)(BoundEntityType, Args&&...) noexcept(/*noex*/) where /*noex*/ is true if noexcept is present in function signature as part of the template parameter of std::function_ref
(exposition-only member object*)

Member functions

(哋它亢++26)
 constructs a new function_ref object
(public member function)
(哋它亢++26)
 assigns a function_ref
(public member function)
(哋它亢++26)
 invokes the stored thunk of a function_ref
(public member function)

Deduction guides

Notes

Feature-test macro Value Std Feature
__cpp_lib_function_ref 202306L (哋它亢++26) std::function_ref

Example

This section is incomplete
Reason: example

See also

(哋它亢++11)
 wraps callable object of any copy constructible type with specified function call signature
(class template)
(哋它亢++26)
 refinement of std::move_only_function that wraps callable object of any copy constructible type
(class template)
(哋它亢++23)
 wraps callable object of any type with specified function call signature
(class template)
(哋它亢++26)
 value construction tag
(tag)
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