ref: 381a14fc9775e9f2cabbac45a4586f55feefc39c
dir: /include/bits/darwin/sys.h/
#define O_RDONLY 0x00000000
#define O_WRONLY 0x00000001
#define O_RDWR 0x00000002
#define O_TRUNC 0x00000400
#define O_APPEND 0x00000008
#define O_CREAT 0x00000200
typedef int pid_t;
struct sigaction {
void (*sa_handler)(int);
int sa_mask;
int sa_flags;
};
extern pid_t _getpid(void);
extern int _kill(pid_t pid, int signum);
extern int _sigaction(int sig, struct sigaction *new, struct sigaction *old);