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

Calls the Callable object, reference to which is stored, as if by INVOKE ( get() , std:: forward < ArgTypes > ( args ) ... ) . This function is available only if the stored reference points to a Callable object.

T must be a complete type.

Parameters

Return value

The return value of the called function.

Exceptions

Example

#include <functional>
#include <iostream>
 
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();
}

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

Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

See also