is-const-class.md

description	title	ms.date	f1_keywords	helpviewer_keywords	ms.assetid
Learn more about: is_const Class	is_const Class	11/04/2016	type_traits/std::is_const	is_const class is_const	55b8e887-9c3f-4a1d-823a-4a257337b205

is_const Class

Tests if type is const.

Syntax

template <class Ty>
struct is_const;

Parameters

Ty
The type to query.

Remarks

An instance of the type predicate holds true if Ty is const-qualified.

Example

// std__type_traits__is_const.cpp
// compile with: /EHsc
#include <type_traits>
#include <iostream>

struct trivial
{
    int val;
};

int main()
{
    std::cout << "is_const<trivial> == " << std::boolalpha
        << std::is_const<trivial>::value << std::endl;
    std::cout << "is_const<const trivial> == " << std::boolalpha
        << std::is_const<const trivial>::value << std::endl;
    std::cout << "is_const<int> == " << std::boolalpha
        << std::is_const<int>::value << std::endl;
    std::cout << "is_const<const int> == " << std::boolalpha
        << std::is_const<const int>::value << std::endl;

    return (0);
}

is_const<trivial> == false
is_const<const trivial> == true
is_const<int> == false
is_const<const int> == true

Requirements

Header: <type_traits>

Namespace: std

See also

<type_traits>
is_volatile Class