std::is_fundamental - cppreference.com (original) (raw)
| | | | | -------------------------------------------- | | ------------- | | template< class T > struct is_fundamental; | | (since C++11) |
std::is_fundamental is a UnaryTypeTrait.
If T is a fundamental type (that is, arithmetic type, void, or nullptr_t), provides the member constant value equal true. For any other type, value is false.
If the program adds specializations for std::is_fundamental or std::is_fundamental_v, the behavior is undefined.
Contents
[edit] Template parameters
[edit] Helper variable template
| template< class T > constexpr bool is_fundamental_v = is_fundamental<T>::value; | | (since C++17) | | ------------------------------------------------------------------------------------- | | ------------- |
Inherited from std::integral_constant
Member constants
| | true if T is a fundamental 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
[edit] Possible implementation
[edit] Example
#include static_assert(std::is_fundamental_v == true); static_assert(std::is_fundamental_v<int&> == false); static_assert(std::is_fundamental_v<int*> == false); static_assert(std::is_fundamental_v == true); static_assert(std::is_fundamental_v<void*> == false); static_assert(std::is_fundamental_v == true); static_assert(std::is_fundamental_v<float&> == false); static_assert(std::is_fundamental_v<float*> == false); static_assert(std::is_fundamental_v<std::nullptr_t> == true); static_assert(std::is_fundamental_v<std::is_fundamental> == false); class A {}; static_assert(std::is_fundamental_v == false); static_assert(std::is_fundamental_v<std::is_fundamental::value_type>); int main() {}