std::is_trivial
Defined in header <type_traits> |
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|---|---|---|
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(since C++11) |
std::is_trivial is a UnaryTypeTrait.
If T is a trivial type, provides the member constant value equal to true. For any other type, value is false.
If std::remove_all_extents_t<T> is an incomplete type and not (possibly cv-qualified) void, the behavior is undefined.
The behavior of a program that adds specializations for std::is_trivial or std::is_trivial_v is undefined.
Template parameters
| T | - | a type to check |
Helper variable template
|
(since C++17) |
Inherited from std::integral_constant
Member constants
|
value
[static]
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true if T is a trivial type, false otherwise (public static member constant) |
Member functions
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operator bool
|
converts the object to bool, returns value (public member function) |
|
operator()
(C++14)
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returns value (public member function) |
Member types
| Type | Definition |
|---|---|
value_type |
bool |
type |
std::integral_constant<bool, value> |
Example
#include <type_traits>
struct A { int m; };
static_assert(std::is_trivial_v<A> == true);
struct B { B() {} };
static_assert(std::is_trivial_v<B> == false);
int main() {}Defect reports
The following behavior-changing defect reports were applied retroactively to previously published C++ standards.
| DR | Applied to | Behavior as published | Correct behavior |
|---|---|---|---|
| LWG 2015 | C++11 | T could be an array of incompleteclass type with unknown bound |
the behavior is undefined in this case |
See also
|
(C++11)
|
checks if a type is trivially copyable (class template) |
|
(C++11)(C++11)(C++11)
|
checks if a type has a default constructor (class template) |
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