这个结构是C11中的POD吗？
struct B
{
int a;
B(int aa) : a(aa) {}
B() = default;
};
请注意,这个问题对C 11是明确的.我知道这个类不是C98或C03中的POD.
有关C 11中POD的说明,请参见trivial vs. standard layout vs. POD
(灵感来自这个问题：Is there a compile-time func/macro to determine if a C++0x struct is POD?)
解决方法
是的,这是根据
new rules的POD.
如果您查阅新标准的§8.4.2/ 4段,您可以看到,如果构造函数在第一个声明中是默认的,则不是用户提供的：
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. (…)
您可以使用std :: is_pod类型trait为您提供带有static_assert的编译器test this.
static_assert(std::is_pod<B>::value,"B should be a POD");
