std::is_literal_type
Defined in header <type_traits> | ||
|---|---|---|
template< class T > struct is_literal_type; | (since C++11) (deprecated in C++17) (removed in C++20) |
If T satisfies all requirements of LiteralType, provides the member constant value equal true. For any other type, value is false.
The behavior is undefined if std::remove_all_extents_t<T> is an incomplete type and not (possibly cv-qualified) void.
Template parameters
| T | - | a type to check |
Helper variable template
template< class T > inline constexpr bool is_literal_type_v = is_literal_type<T>::value; | (since C++17) (deprecated) (removed in C++20) |
Inherited from std::integral_constant
Member constants
| value
[static] | true if T is a literal 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> |
Notes
Only literal types may be used as parameters to or returned from constexpr functions. Only literal classes may have constexpr member functions.
Example
#include <iostream>
#include <type_traits>
struct A {
int m;
};
struct B {
virtual ~B();
};
int main()
{
std::cout << std::boolalpha;
std::cout << std::is_literal_type<A>::value << '\n';
std::cout << std::is_literal_type<B>::value << '\n';
}Output:
true false
See also
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http://en.cppreference.com/w/cpp/types/is_literal_type