c++ - g++ -Wreorder 的意义何在？

Question

g++ -Wall 选项包括 -Wreorder。该选项的作用如下所述。我不清楚为什么有人会关心(尤其是在 -Wall 中默认打开它)。

-Wreorder (C++ only)  Warn when the order of member initializers given in the code does not  match the order in which they must be executed.  For instance:    struct A {      int i;      int j;      A(): j (0), i (1) { }    };  The compiler will rearrange the member initializers for i and j to  match the declaration order of the members, emit-ting a warning to that  effect.  This warning is enabled by -Wall.

Answer 1

考虑:

struct A {
    int i;
    int j;
    A() : j(0), i(j) { }
};

现在 i 被初始化为某个未知值，而不是零。

另外，i 的初始化可能会产生一些副作用，这对顺序很重要。例如

A(int n) : j(n++), i(n++) { }