std::reference_wrapper<T>::operator()

template< class... ArgTypes >
typename std::result_of<T&(ArgTypes&&...)>::type
    operator() ( ArgTypes&&... args ) const;

(since C++11)
(until C++17)

template< class... ArgTypes >
std::invoke_result_t<T&, ArgTypes...>
    operator() ( ArgTypes&&... args ) const;

(since C++17)

Calls the Callable object, reference to which is stored. This function is available only if the stored reference points to a Callable object.

T must be a complete type.

Parameters

args

arguments to pass to the called function

Return value

The return value of the called function.

Exceptions

(none).

Example

#include <iostream>
#include <functional>
 
void f1()
{
    std::cout << "reference to function called\n";
}
void f2(int n)
{
    std::cout << "bind expression called with " << n << " as the argument\n";
}
 
int main()
{
    std::reference_wrapper<void()> ref1 = std::ref(f1);
    ref1();
 
    auto b = std::bind(f2, std::placeholders::_1);
    auto ref2 = std::ref(b);
    ref2(7);
 
    auto c = []{std::cout << "lambda function called\n"; };
    auto ref3 = std::ref(c);
    ref3();
}

Output:

reference to function called
bind expression called with 7 as the argument
lambda function called

std::reference_wrapper<T>::operator()

Parameters

Return value

Exceptions

Example

See also