Defined in header <type_traits> | ||||
---|---|---|---|---|
| (since C++11) |
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
| (since C++17) |
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
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 | #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:
1 2 | true false |
See also
std::experimental::is_literal_type_v
(library fundamentals TS) | variable template alias of std::is_literal_type::value (variable template) |
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