use strict;
use warnings;

use MCE::Child;
use MCE::Channel;

my $chnl = MCE::Channel->new( impl => 'Simple' );

# spin up worker early before creating big hash
mce_child {
    local $SIG{__WARN__} = sub {};
    while ( my ($cmd, @args) = $chnl->recv ) {
        local ($?, $!);
        system($cmd, @args);
        $chnl->send2($?, $!);
    }
};

sub syscmd {
    my $cmd = shift;
    return unless $cmd;

    $chnl->send($cmd, @_);
    my ($status, $errmsg) = $chnl->recv2;
    
    if ($status == -1) {
        print "SYSTEM: failed to execute ($cmd): $errmsg\n";
    }
    elsif ($status & 127) {
        printf "SYSTEM: $cmd died with signal %s, %s coredump\n",
            ($status & 127), ($status & 128) ? 'with' : 'without';
    }
    else {
        printf "SYSTEM: $cmd exited with status %d\n", $status >> 8;
    }
}

# create big hash
my %big_hash;

# pass command and optionally args
syscmd('ls');

# attempt to run a command not found
syscmd('something');

# sleep for 2 seconds
syscmd('sleep', '2');

# notify no more work, then reap worker
$chnl->end;
MCE::Child->waitall;