#ifndef _SYS_FILE_H
#define _SYS_FILE_H 1
#include <sys/cdefs.h>
__BEGIN_DECLS
#define LOCK_UN 0
#define LOCK_EX 1
#define LOCK_SH 2
#define LOCK_NB 4
int flock(int fd, int op);
__END_DECLS
#endif