On Wed, 07 Apr 2004 13:51:03 -0500
"JupiterHost.Net" <[EMAIL PROTECTED]> wrote:
> perldoc -f flock says
>
> "If LOCK_NB is bitwise-or'ed with LOCK_SH or LOCK_EX then "flock"
> will return immediately rather than blocking waiting for the lock
> (check the return status to see if you got it)."
>
> So that would mean:
>
> use Fcntl ':flock';
>
> flock(FH, LOCK_EX || LOCK_NB) or die "Lock failed $!";
> ...
> flock FH, LOCK_UN;
Not quite. The bitwise or operator is '|' not '||'. What you have
sets the 2nd argument to true or 1 which is not what you want.
> If so, does the numeric values work the same way?
The numeric values work the same, but I strongly encourage use of the
manifest constants. It makes the code more portable and easier to read.
> flock(FH, 1 || 4) or die "Lock failed $!";
> ...
> flock FH, 8;
>
> correct?
>
> If you do the (LOCK_EX || LOCK_NB) or (1 || 4) is the return code
> different depending on the type of lock received?
>
> IE
> my $rc = flock(FH, LOCK_EX || LOCK_NB);
> if($rc == 4) { warn "rats! Exclusive lock not granted, oh well...";
> } if(!$rc) { die "Could not get lock no how mr flock guy!"; }
The return code with LOCK_NB is false if the file is locked by another
process, true is you got the lock. $! holds the appropriate error
message.
--
Smoot Carl-Mitchell
Systems/Network Architect
email: [EMAIL PROTECTED]
cell: +1 602 421 9005
home: +1 480 922 7313
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