sub msg {
    $msg_num = @_[0];
    $msg_txt = "$msg_num $msgs{$msg_num}";
    print "HTTP/1.0 $msg_txt\n";
}

##</code><code>##

%msgs = ("200", "OK", 
         "400", "Bad Request",
         "403", "Forbidden", 
         "404", "Not Found", 
         "500", "Internal Server Error");

##</code><code>##

&msg(400);

##</code><code>##

HTTP/1.0 400 Bad Request

##</code><code>##

if ($proto ne "HTTP/1.0") { 
    &msg(400); 
}

##</code><code>##

HTTP/1.0 400