1/* Copyright (C) 1991-2025 Free Software Foundation, Inc.
 2   This file is part of the GNU C Library.
 3
 4   The GNU C Library is free software; you can redistribute it and/or
 5   modify it under the terms of the GNU Lesser General Public
 6   License as published by the Free Software Foundation; either
 7   version 2.1 of the License, or (at your option) any later version.
 8
 9   The GNU C Library is distributed in the hope that it will be useful,
10   but WITHOUT ANY WARRANTY; without even the implied warranty of
11   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
12   Lesser General Public License for more details.
13
14   You should have received a copy of the GNU Lesser General Public
15   License along with the GNU C Library; if not, see
16   <https://www.gnu.org/licenses/>.  */
17
18#ifndef	_SYS_FILE_H
19#define	_SYS_FILE_H	1
20
21#include <features.h>
22
23#ifndef	_FCNTL_H
24# include <fcntl.h>
25#endif
26
27__BEGIN_DECLS
28
29
30/* Alternate names for values for the WHENCE argument to `lseek'.
31   These are the same as SEEK_SET, SEEK_CUR, and SEEK_END, respectively.  */
32#ifndef L_SET
33# define L_SET	0	/* Seek from beginning of file.  */
34# define L_INCR	1	/* Seek from current position.  */
35# define L_XTND	2	/* Seek from end of file.  */
36#endif
37
38
39/* Operations for the `flock' call.  */
40#define	LOCK_SH	1	/* Shared lock.  */
41#define	LOCK_EX	2 	/* Exclusive lock.  */
42#define	LOCK_UN	8	/* Unlock.  */
43
44/* Can be OR'd in to one of the above.  */
45#define	LOCK_NB	4	/* Don't block when locking.  */
46
47
48/* Apply or remove an advisory lock, according to OPERATION,
49   on the file FD refers to.  */
50extern int flock (int __fd, int __operation) __THROW;
51
52
53__END_DECLS
54
55#endif /* sys/file.h  */