std::is_function

 

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is_void (C++11) is_array (C++11) is_pointer (C++11) is_enum (C++11) is_union (C++11) is_class (C++11) is_function (C++11)	is_object (C++11) is_scalar (C++11) is_compound (C++11) is_integral (C++11) is_floating_point (C++11) is_fundamental (C++11) is_arithmetic (C++11)
is_reference (C++11)
is_lvalue_reference (C++11)
is_rvalue_reference (C++11)
is_member_pointer (C++11)
is_member_object_pointer (C++11)
is_member_function_pointer (C++11)

Type properties
is_const (C++11) is_volatile (C++11) is_pod (C++11) is_empty (C++11) is_polymorphic (C++11) is_abstract (C++11)	is_trivial (C++11) is_trivially_copyable (C++11) is_standard_layout (C++11) is_literal_type (C++11) is_signed (C++11) is_unsigned (C++11)
Supported operations
is_constructible is_trivially_constructible is_nothrow_constructible (C++11) (C++11) (C++11)
is_default_constructible is_trivially_default_constructible is_nothrow_default_constructible (C++11) (C++11) (C++11)
is_copy_constructible is_trivially_copy_constructible is_nothrow_copy_constructible (C++11) (C++11) (C++11)
is_move_constructible is_trivially_move_constructible is_nothrow_move_constructible (C++11) (C++11) (C++11)
is_assignable is_trivially_assignable is_nothrow_assignable (C++11) (C++11) (C++11)
is_copy_assignable is_trivially_copy_assignable is_nothrow_copy_assignable (C++11) (C++11) (C++11)
is_move_assignable is_trivially_move_assignable is_nothrow_move_assignable (C++11) (C++11) (C++11)
is_destructible is_trivially_destructible is_nothrow_destructible (C++11) (C++11) (C++11)
has_virtual_destructor (C++11)
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Type trait constants
integral_constant (C++11)

 

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>

Example

#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

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)