1 /* Copyright (C) 1994, 1996, 1997, 1998, 2000 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Library General Public License as
6 published by the Free Software Foundation; either version 2 of the
7 License, or (at your option) any later version.
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 Library General Public License for more details.
14 You should have received a copy of the GNU Library General Public
15 License along with the GNU C Library; see the file COPYING.LIB. If not,
16 see <http://www.gnu.org/licenses/>. */
19 #include <sys/types.h>
25 /* lockf is a simplified interface to fcntl's locking facilities. */
27 int lockf (int fd
, int cmd
, off_t len
)
31 memset ((char *) &fl
, '\0', sizeof (fl
));
33 /* lockf is always relative to the current file position. */
34 fl
.l_whence
= SEEK_CUR
;
41 /* Test the lock: return 0 if FD is unlocked or locked by this process;
42 return -1, set errno to EACCES, if another process holds the lock. */
44 if (fcntl (fd
, F_GETLK
, &fl
) < 0)
46 if (fl
.l_type
== F_UNLCK
|| fl
.l_pid
== getpid ())
69 return fcntl(fd
, cmd
, &fl
);
71 libc_hidden_def(lockf
)