[ILUG] [OT] perl: file locking with flock

[Kathryn Cassidy]

Agh!  I've got a wee script here which is meant to put an exclusive lock on
a file, wait for a minute, then release the lock.  It goes something like
this:

    open LOCKED, '>>oqq.inc';

	$result=flock(LOCKED, LOCK_EX);

	if ($result == 0) {
		sleep 60;
		flock(LOCKED, LOCK_UN);
	}
	else {
		print "bugger";
	}

    close(LOCKED);
   

Now, I'm having a bit of a problem here as it appears that I can run two
instances of this script simultaneously with no problems.  This suggests
that more than one process is able to put an exclusive lock on the file.
Now, maybe I don't understand file locking as well as I thought I did, but
surely the whole point of an exclusive lock is that it's exclusive?

Anyone want to tell me what I'm doing wrong?