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/*---------------------------------------------------------------------------*\
NAME
flock.c - flock(2), emulated (more or less) in terms of
lockf(3)
BUGS
Doesn't support shared locks.
LICENSE
This source code is released under a BSD-style. See the LICENSE
file for details.
Copyright (c) 2011-2015 Brian M. Clapper, bmc@clapper.org
\*---------------------------------------------------------------------------*/
/*---------------------------------------------------------------------------*\
Includes
\*---------------------------------------------------------------------------*/
#include <unistd.h>
#include <errno.h>
#ifdef HAVE_SYS_FILE_H
#include <sys/file.h>
#endif /* HAVE_SYS_FILE_H */
#include "config.h"
#include "flock.h"
/*---------------------------------------------------------------------------*\
Public Routines
\*---------------------------------------------------------------------------*/
int flock(int fd, int op)
{
int cmd = 0;
errno = 0;
if (op & LOCK_UN)
cmd = F_ULOCK;
else if (op & LOCK_SH) /* can't emulate shared lock with lockf() */
errno = EINVAL;
else if (op & LOCK_NB)
cmd = F_TLOCK;
else
cmd = F_LOCK;
return lockf(fd, cmd, 0);
}
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