# get office_id for this office
my $office_id = get_office_id();
if ($office_id) {
   # found an office
} else {
   # no office found
}

##</code><code>##

# get office_id for this office
my $office_id = get_office_id();
if (defined $office_id) {
   # found an office
} else {
   # no office found
}

##</code><code>##

# get office_id for this office
my ($ok, $office_id) = get_office_id();
if ($ok) {
   # found an office
} else {
   # no office found
}