Bug #119356 for Proc-PID-File: Proc::PID::File should not die on all flock errors

Hi, I'm trying to use Proc::PID::File to discover if I a script is already running or not. It should return 0, or the pid of the running process, but I have found that sometimes instead the script just dies with a 'Resource temporarily unavailable' error. This seems to be the way this error is handled from flock(). The error seems to happen when the timing is JUST right so that 2 copies of the script try to create & lock the pid file at the same exact instant. The result is that instead of Proc::PID::File->running() (or alive) returning true or not true, the script will just die() unexpectedly. It is very rare under normal circumstances making it hard to debug, but here is a concocted example script that shows the problem: Run this script 10 times at once in bash; In rare cases, an instance of the script will exit without executing either "Running..." print statement. (IE if I run 10 copies at once in bash, I should see "Running Yes/No" 10 times but instead sometimes I will see only 9 + an error). Execute it as: ./flocktest.pl &./flocktest.pl &./flocktest.pl &./ flocktest.pl &./flocktest.pl &./flocktest.pl &./flocktest.pl &./flocktest.pl &./flocktest.pl &./flocktest.pl ----------- flocktest.pl ---------------------- #!/usr/bin/perl use strict; use warnings; use Proc::PID::File; my $waitcount = 0; # Check we arent running twice at once while(Proc::PID::File->running( dir => '/tmp' )) { if($waitcount++ > 90) { print "Running Yes: Pid file exists, tried $waitcount times, could not get a lock\n"; # do something important here before dieing exit 3; } select undef, undef, undef, 0.1; } print "Running No: Got the lockfile ourselves\n"; exit 0; ------------------------------------------ I'm not sure what the solution is, perhaps just returning true when flock() fails, or maybe retrying it a few times before dieing? Or maybe just a warning in the documentation that it could die() under 'normal' conditions. Thanks, -- -Alex