关于函数指针

int func_s(int){return 1;}
typedef int (*FUNC_C)(int);
FUNC_C f = func_s;   //(1)
FUNC_C f = &func_s;  //(2)

 foo就是编译器看到了强转成foo()的地址，&foo编译器当取foo()的地址 

http://stackoverflow.com/questions/6893285/why-do-all-these-crazy-function-pointer-definitions-all-work-what-is-really-goi

http://stackoverflow.com/questions/9552663/function-pointers-and-address-of-a-function

老外解释，不可言传