sub daemonize {
    # try to daemonize
    if (success) {
	return 1 
    } else {
	return errstr
    }
}

##</code><code>##

$isdaemon = daemonize()
if ($isdaemon ne "1") {
    print "error: $isdaemon";    
}

##</code><code>##

if (! daemonize) {
    report error
}

##</code><code>##

open($fh, file) or die "$!";

##</code><code>##

use Scalar::Util;
sub daemonize {
    # try to daemonize
    if (success) {
	return 1 
    } else {
	return dualvar 0, errstr
    }
}

##</code><code>##

$isdaemon = daemonize;
if ($isdaemon == 0) {
    print "error: $isdaemon";
}