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Date: Sun, 04 Nov 2001 13:33:05 -0600
From: Steven Lembark <lembark@wrkhors.com>
Reply-To: lembark@wrkhors.com
To: modperl@apache.org
Subject: Re: Are global variables truly global?
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In-Reply-To: <9DB60AFDAB1A5E4093762030DBB38978103ED2@WEBSERVER.advdata.com.au>
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-- "Chui G. Tey" <chui.tey@advdata.com.au>

> I have some state data that I need to persist between requests. At the
> moment these are COM objects, but they'll be ported to Perl Classes. It
> is quite important that only one of these instances exist per web
> server. These instances are too large to write and read to file on every
> request. So I have defined the variable as a package level variable.
>
> I have been instantiating the variable in my handler() routine if it has
> not already been instantiated. ie.

Global variables are exactly that: global. If you use
something like:

    our $foo ||= somefunc;

or

    our $foo = Someclass->constructor( @blah );

then you'll get a value that goes into the symbol table and
is unique w/in the executing process. Thing you'll need to
read up on are global variables, packages/namespaces and
how "use strict" effects things (all of which are in the Camel
or Llama books).

--
Steven Lembark                               2930 W. Palmer
Workhorse Computing                       Chicago, IL 60647
                                            +1 800 762 1582