正确，这是有效的C ++ 14;然而，在C ++ 11中，类成员初始化中的类不是聚合，因此在C中无效++ 11。

You are correct, this is valid C++14; however, in C++11 a class with in class member initializers was not an aggregate and so this is not valid in C++11.

我在回答上述问题时提到的问题，后来我发表了我的初步意见后意识到， gcc不支持此更改，直到5.0 （ 查看活动

The issue as I noted in my answer to the above question and I realized later after I made my initial comment is that gcc did not support this change until 5.0 (see it live):

支持具有非静态数据成员
初始化器的C ++ 14聚合。

G++ now supports C++14 aggregates with non-static data member initializers.

struct A { int i, j = i; };
A a = { 42 }; // a.j is also 42