#define sigemptyset(set) (*(set) = 0, 0)
这是什么意思？
struct sigaction new_sa;
sigemptyset(&new_sa.sa_mask);
struct sigaction {
//...
sigset_t sa_mask; /* signal mask to apply */
//...
};
typedef __darwin_sigset_t sigset_t;
typedef __uint32_t __darwin_sigset_t
typedef unsigned int __uint32_t;
