std::is_volatile - cppreference.com

From cppreference.com


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

std::is_volatile is a UnaryTypeTrait.

If T is a volatile-qualified type (that is, volatile, or const volatile), provides the member constant value equal to true. For any other type, value is false.

If the program adds specializations for std::is_volatile or std::is_volatile_v, the behavior is undefined.

Template parameters

Helper variable template

`template< class T > constexpr bool is_volatile_v = is_volatile<T>::value;`		(since C++17)

Inherited from std::integral_constant

Member constants

true if T is a volatile-qualified type, false otherwise
(public static member constant)

Member functions

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

Member types

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

Possible implementation

template<class T> struct is_volatile : std::false_type {};
template<class T> struct is_volatile<volatile T> : std::true_type {};

Example

#include <type_traits>
#include <valarray>

static_assert(!std::is_volatile_v<int>);
static_assert(std::is_volatile_v<volatile int>);
static_assert(std::is_volatile_v<volatile const int>);
static_assert(std::is_volatile_v<volatile std::valarray<float>>);
static_assert(!std::is_volatile_v<std::valarray<volatile float>>);

int main() {}