给定一个静态成员变量，它是从静态成员变量初始化的另一个班级，非字面意思struct ii有时默认初始化为0 or to 333。这取决于编译或链接顺序。伪代码展示：
class StaticClass: // file 'ONE.cpp/.hpp'
static int i = 2
static struct ii { int a = 333 }
class ABC: // file 'abc.cpp'
static int abc_i = StaticClass::i // always 2
static struct abc_ii = StaticClass::ii // sometimes 0, sometimes 333
Calling g++ -std=c++11 abc.cpp ONE.cpp && ./a.out结果是i = 2 / ii = 0（gcc 4.8.1，与 clang++ 3.7 相同；-Wall -Wextra从不抱怨）。
但打电话g++ -std=c++11 ONE.cpp abc.cpp && ./a.out结果是i = 2 / ii = 333 !
同样的情况发生在ONE.o abc.o vs abc.o ONE.o以及以一种或另一种方式连接文件时：
cat ONE.cpp abc.cpp > X.cpp && g++ X.cpp && ./a.out vs
cat abc.cpp ONE.cpp > Y.cpp && g++ Y.cpp && ./a.out
删除包含并在单个文件中移动代码，当存在以下顺序时，默认初始化为 0：
const OneI ABC::def_ii = StaticClass::ii; const OneI StaticClass::ii = OneI{333};
1 到 333 的顺序如下：
const OneI StaticClass::ii = OneI{333}; const OneI ABC::def_ii = StaticClass::ii;
为什么两个独立的编译单元会发生这种情况？是否可以通过始终强制执行后者的顺序来以某种方式避免这种情况？正在使用静态指针ABC to StaticClass::ii安全（不过我不想）？
完整的C++代码：
/* File: abc.cpp */
#include <iostream>
#include "ONE.hpp"
struct ABC {
ABC();
static const int def_i;
static const OneI def_ii;
void arg_i(const int &x) { std::cout << "i = " << x << " ";};
void arg_ii(const OneI &x) { std::cout << "/ ii = " << x.a << " ";};
};
ABC::ABC() {
arg_i(def_i);
arg_ii(def_ii);
}
const int ABC::def_i = StaticClass::i;
const OneI ABC::def_ii = StaticClass::ii;
int main() {
ABC a;
std::cout << '\n';
}
/* End: abc.cpp */
/* File: ONE.cpp */
#include <iostream>
#include "ONE.hpp"
const int StaticClass::i = 2;
const OneI StaticClass::ii = OneI{333};
/* End: ONE.cpp */
/* File: ONE.hpp */
#include <iostream>
#ifndef One
#define One
struct OneI {
OneI(int a_) : a(a_) { }
int a;
};
struct StaticClass {
const static int i;
const static OneI ii;
};
#endif // One header guard
/* End: ONE.hpp */
