We are planning to upgrade our servers from IBM AIX - V5.1 to V5.2. But the existing perl codes which work fine in AIX - V5.1(perl5.6.0) are hanging in AIX - V5.2(perl5.8.0). The reason is this.

We have four perl scripts a)loader, b)load_domain, c)run_command and d)execute command. loader triggers, load_domain which in turn triggers run_command which in turn triggers execute_command. The perl script execute_command triggers Unix shell scripts.

The perl script run_command is not able to reap the process id of it's grandchild(the one triggered by execute_command). The command used was waitpid(-1, WNOHANG).

This command gets the process id of it's grandchild but the return code is a negative 1 (-1). So the unidentified grand child script stays as a zombie and the grandfather perl script(run_command) hangs indefinitely.

The following piece of code is used to reap the grandchild. ************************************************************

sub loader_process_reaper {
    use POSIX qw/:sys_wait_h/;

    while ((my $pid = waitpid(-1, WNOHANG)) != -1) {
    if (WIFEXITED($?)) {
        $domain_loaders{$pid}{SYSTEM_STATUS} = WEXITSTATUS($?);
        $domain_loaders{$pid}{LOADER_STATUS} = RETURNED;
        }
    }
    }
[download]

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Could someone please tell us why this happens. We are breaking our head over this issue.

Thanks,

Karthik

Edit g0n - added code & formatting tags