std::is_volatile
Defined in header <type_traits> | ||
|---|---|---|
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
| T | - | a type to check |
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
|
value
[static] |
true if T is a volatile-qualified type, 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> |
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() {}
See also
|
(C++11) | checks if a type is const-qualified (class template) |
|
(C++26) | checks if reflection represents a volatile type or a function type with volatile qualifier (function) |
|
(C++26) | checks if reflection represents a volatile-qualified type (function) |
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