if ($some_condition) {
    return $X;
} else {
    return $Y;
}

die "not reached"; # but see comment below

##</code><code>##

 is only avaliable with the XS version at /usr/lib/perl5/site_perl/5.8.5/Compress/Zlib.pm line 9

##</code><code>##

  if (grep { /^(dualvar|set_prototype)$/ } @_ ) {
    require Carp;
    Carp::croak("$1 is only avaliable with the XS version");
  }