class template
<type_traits>
std::is_trivially_copy_assignable
template <class T> struct is_trivially_copy_assignable;
Is trivially copy assignable
Trait class that identifies whether T is a trivially copy assignable type.
The class inherits from integral_constant as being either true_type or false_type, depending on whether T is trivially copy assignable.
Template parameters
- T
- A complete type, or void (possible cv-qualified), or an array of unknown bound.
Member constants
Inherited from integral_constant:
| member constant | definition |
|---|
| value | either true or false |
Example
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
|
// is_trivially_copy_assignable example
#include <iostream>
#include <type_traits>
struct A { };
struct B : A {};
struct C { C& operator= (const A&){return *this;} };
int main() {
std::cout << std::boolalpha;
std::cout << "is_trivially_copy_assignable:" << std::endl;
std::cout << "int=short: " << std::is_trivially_copy_assignable<int,short>::value << std::endl;
std::cout << "A=A: " << std::is_trivially_copy_assignable<A,A>::value << std::endl;
std::cout << "A=B: " << std::is_trivially_copy_assignable<A,B>::value << std::endl;
std::cout << "B=A: " << std::is_trivially_copy_assignable<B,A>::value << std::endl;
std::cout << "C=A: " << std::is_trivially_copy_assignable<C,A>::value << std::endl;
return 0;
}
| |
Output:
is_trivially_copy_assignable:
int=short: true
A=A: true
A=B: false
B=A: true
C=A: false
|