用 C 实现 yield 功能， gcc 与 clang 编译结果不一样？

http://coolshell.cn/articles/10975.html

#include <stdio.h>
#define Begin() static int state=0; switch(state) { case 0:
#define Yield(x) do { state=__LINE__; return x; case __LINE__:; } while (0)
#define End() }

int function(void) {
  static int i;
  Begin();
  for (i = 0; i < 10; i++)
    Yield(i);
  End();
}

int main(){
    int j;
    for(j = 0; j < 20; j++){
        printf("%d | ", function());
    }
    printf ("\n");
    return 0;
}