Re: flock return value / bit wise or'd LOCK_NB

[JupiterHost.Net]

Smoot Carl-Mitchell wrote:

On Wed, 07 Apr 2004 14:50:54 -0500
"JupiterHost.Net" <[EMAIL PROTECTED]> wrote:

So flock(FH, LOCK_EX | LOCK_NB) then?


Yes.



So:
my $rc = flock(FH, LOCK_EX | LOCK_NB);
if($rc == 0) { warn "rats! Exclusive lock not granted, oh well..."; } 
if(!defined $rc) { die "Could not get lock no how mr flock guy!"; }

or

if(!$rc) { $! =~ m/No Lock/ ? warn "not exclusive but locked - $!" :
die "no lock - $!"; }


If $rc is zero, you likely did not get the lock. You might have a zero
return code with a parameter error, in which case $! is set to a
different message.
Here is a little script I used to test all this.  I ran the script and
backgrounded it on my Linux box.  I then ran a second copy to see what
the return code and $! are when the lock is grabbed by the first
process.
#!/usr/bin/perl -w

use strict;                                                             
use Fcntl ':flock';
                                                                        
open(ZZZ, ">zzz");
                                                                        
my $ret = flock(ZZZ, LOCK_EX | LOCK_NB);
print "$ret $!\n";
sleep 60;



Thanks for the info BTW I really appreciate it! :)


No problem.

Excellent I'll give that go and experiment away, thanks a bunch for the 
great idea!

HAGO

Lee.M - JupiterHost.Net


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