RAISERROR

raiserror( { msg_id | msg_string }, severity, state)

msg_id typically >=50000
severity 0..16
state 0..255 (location identifier)

Perl package 'constants'

If you use variables as 'constants', and you want to use them in a package, they should be defined in a BEGIN block inside the package, which (I think) is run as soon as the package is parsed by Perl.

package Map;
{
use Carp;

local ($s);

BEGIN {
$s = sqrt(2);
}
}

I think this is the same problem I recently came across here - if you define your 'constants' in the outermost scope of the package, you won't find them set when your script runs. It seems like they get re-initialised to undef at some point after they're defined.

(Btw in modern versions of Perl the 'use constant' pragma is a much better way of defining constants.)