类模板
<type_traits>
std::is_trivially_constructible
template <class T, class... Args> struct is_trivially_constructible;
Is trivially constructible
模板参数
- T
- 一个完整类型，或者void（可能带 cv 限定），或者一个未知边界的数组。
- Args
- A list of complete types (orvoid, possibly cv-qualified, or an array of unknown bound) representing the argument types for the constructor form, in the same order as in the constructor.
If omitted, it checks whether the type is trivially default-constructible.
示例
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// is_trivially_constructible example
#include <iostream>
#include <type_traits>
struct A { };
struct B { B(){} }; // non-trivial default ctor.
int main() {
std::cout << std::boolalpha;
std::cout << "is_trivially_constructible:" << std::endl;
std::cout << "A(): " << std::is_trivially_constructible<A>::value << std::endl;
std::cout << "A(A): " << std::is_trivially_constructible<A,A>::value << std::endl;
std::cout << "B(): " << std::is_trivially_constructible<B>::value << std::endl;
std::cout << "B(B): " << std::is_trivially_constructible<B,B>::value << std::endl;
return 0;
}
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输出
is_trivially_constructible:
A(): true
A(A): true
B(): false
B(B): true
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