std::is_convertible

 

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Defined in header <type_traits>
template< class From, class To > struct is_convertible;		(since C++11)

If an imaginary rvalue of type From can be used in the return statement of a function returning To, that is, if it can be converted to To using implicit conversion, provides the member constant value equal to true. Otherwise value is false.

Helper variable template

template< class From, class To > constexpr bool is_convertible_v = is_convertible<From, To>::value;		(since C++17)

Inherited from std::integral_constant

Member constants

value [static]

true if From is convertible to To , false otherwise (public static member constant)

Member functions

operator bool	converts the object to bool, returns value (public member function)
operator() (C++14)	returns value (public member function)

Member types

Type	Definition
value_type	bool
type	std::integral_constant<bool, value>

Notes

Gives well-defined results for reference types, void types, array types, and function types.

Example

Run this code

#include <iostream>
#include <type_traits>
 
int main() 
{
    class A {};
    class B : public A {};
    class C {};
 
    bool b2a = std::is_convertible<B*, A*>::value;
    bool a2b = std::is_convertible<A*, B*>::value;
    bool b2c = std::is_convertible<B*, C*>::value;
 
    std::cout << std::boolalpha;
    std::cout << b2a << '\n';
    std::cout << a2b << '\n';
    std::cout << b2c << '\n';
}

Output:

true
false
false

See also

std::experimental::is_convertible_v (library fundamentals TS)

variable template alias of std::is_convertible::value (variable template)