std::is_function

From cppreference.com

Defined in header `<type_traits>`

template< class T > struct is_function;		(since C++11)

If T is function type (but not std::function, lambda expression or another callable object type), provides the member constant value equal true. For any other type, value is false.

Inherited from std::integral_constant

Member constants


value [static]	true if `T` is a function type , false otherwise (public static member constant)

Member functions


operator bool	converts the object to bool, returns `value` (public member function)

Member types


Type	Definition

`value_type`	`bool`

`type`	std::integral_constant<bool, value>

[edit] Example

run this code

#include <iostream>
#include <type_traits>
 
struct A {};
 
int f()
{
    return 1;
}
 
int main() 
{
    std::cout << std::boolalpha;
    std::cout << std::is_function<A>::value << '\n';
    std::cout << std::is_function<int(int)>::value << '\n';
    std::cout << std::is_function<decltype(f)>::value << '\n';
    std::cout << std::is_function<int>::value << '\n';
}

Output:

false
true
true
false

[edit] See also


is_object (C++11)	checks if a type is object type (class template)

is_class (C++11)	checks if a type is a class type (but not union type) (class template)

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)