这个结构POD在C 11？

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");

原文地址：https://www.jb51.cc/c/114298.html