What I was trying to do earlier is use a database handle from run_on_finish()

The child inherited the database handle and closed it. P::FM uses exit when it should probably use POSIX's _exit. finish is simply a call to exec, so if you call _exec instead of finish, that problem should go away.

That means you should replace 

for(my $i=0; $i< @hosts; $i++){
    $pm->start($hosts[$i]) and next;   
    system(@some_command);
    $return_code = $? >> 8;
    $pm->finish($return_code);
}

[download]
with 
use POSIX qw( _exit );

for(my $i=0; $i< @hosts; $i++){
    $pm->start($hosts[$i]) and next;   
    system(@some_command);
    $return_code = $? >> 8;
    _exit($return_code);
}

[download]

Of course, system + _exit is a silly way of doing exec, so you get: 

for my $host (@hosts) {
    $pm->start($host) and next;   
    exec(@some_command);
}

[download]

Error checking added: 

for my $host (@hosts) {
    $pm->start($host) and next;   
    exec(@some_command);
    print(STDERR "exec failed: $!\n");
    _exit($!);
}

[download]

That also fixes the bug where you'd return zero (success) when the child died from a signal.

Update: Clean up.

In reply to Re^3: Parallel::ForkManager run_on_finish exit code handler by ikegami
in thread Parallel::ForkManager run_on_finish exit code handler by sojourn548

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