1/* Copyright (C) 1991-2018 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 <http://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#define __LOCK_ATOMIC 16 /* Atomic update. */
44
45/* Can be OR'd in to one of the above. */
46#define LOCK_NB 4 /* Don't block when locking. */
47
48
49/* Apply or remove an advisory lock, according to OPERATION,
50 on the file FD refers to. */
51extern int flock (int __fd, int __operation) __THROW;
52
53
54__END_DECLS
55
56#endif /* sys/file.h */
57