1 #ifndef _SYS_FILE_H 2 #define _SYS_FILE_H 3 4 #include <features.h> 5 #include <fcntl.h> 6 7 #ifndef L_SET 8 9 #define L_SET 0 /* absolute offset */ 10 #define L_INCR 1 /* relative to current offset */ 11 #define L_XTND 2 /* relative to end of file */ 12 13 #endif 14 15 #ifndef LOCK_SH 16 17 /* Operations for the `flock' call. */ 18 #define LOCK_SH 1 /* Shared lock. */ 19 #define LOCK_EX 2 /* Exclusive lock. */ 20 #define LOCK_UN 8 /* Unlock. */ 21 22 /* Can be OR'd in to one of the above. */ 23 #define LOCK_NB 4 /* Don't block when locking. */ 24 25 #endif 26 27 __BEGIN_DECLS 28 29 /* Apply or remove an advisory lock, according to OPERATION, 30 on the file FD refers to. */ 31 extern int flock __P ((int __fd, int __operation)); 32 33 __END_DECLS 34 35 #endif 36