I am using Proc::Simple module to fork 5 child processes. I polling the processes to check if the processes are still running or not. If poll function does not return anything, we are using the exit_status() function to check the exit status of the child process.

Sometime it is happening like, the exit_status function is returning -1 although I can see that the child process has done it's job. I am not getting this problem everyday. But every 5-7 days I can see in the log that one of the processes returned exit status as -1.

Please find the sample code snippet below.

my $proc = Proc::Simpler->new();
....
...

if($proc->poll){
  # process is running
} else {
  # process not running
  # call exit_status function 
  # my $exit_status = $proc->exit_status();
  # if exit_status returns true, log error for that process
 
}
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I want to know why it happens like sometime, the exit_status returns -1 and what should be done to resolve this issue?