std::reference_wrapper::operator()

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< cpp | utility | functional | reference wrapper


template< class... ArgTypes > typename std::result_of<T&(ArgTypes&&...)>::type operator() ( ArgTypes&&... args ) const;		(since C++11)

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

#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

[edit] See also


get operator T&	accesses the stored reference (public member function)

Language
Standard library headers
Concepts
Utilities library
Strings library
Containers library
Algorithms library
Iterators library
Numerics library
Input/output library
Localizations library
Regular expressions library (C++11)
Atomic operations library (C++11)
Thread support library (C++11)

std::reference_wrapper::operator()

Contents

[edit] Parameters

[edit] Return value

[edit] Exceptions

[edit] Example

[edit] See also