Is this struct POD in C++11?
Is this struct a POD in C++11?
struct B
{
int a;
B(int aa) : 开发者_如何转开发a(aa) {}
B() = default;
};
Note that this question is explicit about C++11. I know that this class is not a POD in C++98 nor C++03.
For an explanation of POD in C++11, see trivial vs. standard layout vs. POD
(Inspired by this question: Is there a compile-time func/macro to determine if a C++0x struct is POD? )
Yes, it is a POD according to the new rules.
If you look up paragraph §8.4.2/4 of the new standard, you can see that if a constructor is defaulted on the first declaration, it is not user-provided:
Explicitly-defaulted functions and implicitly-declared functions are collectively called defaulted functions, and the implementation shall provide implicit definitions for them (§12.1 §12.4, §12.8), which might mean defining them as deleted. A special member function is user-provided if it is user-declared and not explicitly defaulted or deleted on its first declaration. (...)
You can use the std::is_pod
type trait to have the compiler test this for you with static_assert
.
static_assert(std::is_pod<B>::value, "B should be a POD");
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