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/* Copyright (C) 1993, 1995 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If
not, write to the Free Software Foundation, Inc., 675 Mass Ave,
Cambridge, MA 02139, USA. */
#include <ansidecl.h>
#include <errno.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/file.h>
/* Apply or remove an advisory lock, according to OPERATION,
on the file FD refers to. */
int
DEFUN(__flock, (fd, operation), int fd AND int operation)
{
struct flock flock;
int cmd;
#ifdef __linux__
/* We try the system call first. */
cmd = __syscall_flock (fd, operation);
if (cmd == 0 || (cmd < 0 && errno != ENOSYS))
{
return cmd;
}
errno = 0;
#endif
switch (operation & ~LOCK_NB) {
case LOCK_SH:
#ifdef __linux__
flock.l_type = F_SHLCK;
#else
flock.l_type = F_RDLCK;
#endif
break;
case LOCK_EX:
#ifdef __linux__
flock.l_type = F_EXLCK;
#else
flock.l_type = F_WRLCK;
#endif
break;
case LOCK_UN:
flock.l_type = F_UNLCK;
break;
default:
errno = EINVAL;
return -1;
}
flock.l_whence = SEEK_SET;
flock.l_start = flock.l_len = 0L;
cmd = (operation & LOCK_NB) ? F_SETLK : F_SETLKW;
return (__fcntl (fd, cmd, &flock));
}
#include <gnu-stabs.h>
#ifdef weak_alias
weak_alias (__flock, flock);
#endif
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