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

From cppreference.com
< cpp‎ | utility‎ | functional‎ | function
 
 
Utilities library
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Relational operators (deprecated in C++20)
 
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Old binders and adaptors
(until C++17*)
(until C++17*)
(until C++17*)
(until C++17*)  
(until C++17*)
(until C++17*)(until C++17*)(until C++17*)(until C++17*)
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(until C++17*)(until C++17*)

(until C++17*)
(until C++17*)(until C++17*)(until C++17*)(until C++17*)
(until C++20*)
(until C++20*)
 
 
const std::type_info& target_type() const noexcept;
(since C++11)

Returns the type of the stored function.

Contents

[edit] Parameters

(none)

[edit] Return value

typeid(T) if the stored function has type T, otherwise typeid(void)

[edit] Example

#include <functional>
#include <iostream>
 
int f(int a) { return -a; }
void g(double) {}
int main()
{
    // fn1 and fn2 have the same type, but their targets do not
    std::function<int(int)> fn1(f),
                            fn2([](int a) {return -a;});
    std::cout << fn1.target_type().name() << '\n'
              << fn2.target_type().name() << '\n';
 
    // since C++17 deduction guides (CTAD) can avail
    std::cout << std::function{g}.target_type().name() << '\n';
}

Possible output:

PFiiE
Z4mainEUliE_
PFvdE

[edit] See also

obtains a pointer to the stored target
(public member function) [edit]
contains some type’s information, the class returned by the typeid operator
(class) [edit]
typeid queries information of a type, returning a std::type_info object representing the type
(operator)