#include <stdio.h>

int main(){
    const int a = 10;
    *(int*)(&a) = 9; //modify a
    printf("%d", a);
    return 0;
}

上面这段代码在VS里有效修改了a，结果为9
在Xcode里为10
为何

——————————————
stackoverflow 有点狠啊，一刷新就有答案了
http://stackoverflow.com/questions/30118051/modification-of-const-int-through-a-non-const-pointer