use lib

Is it recommendable to use the pragma "use lib " when installing a
program on a server shared by many users?
Assuming my IPS did not install certain CPAN modules which my needs, and
I decide to install them in my www directory.
In such a scenario, putting "use lib" on my scripts will add my module
directory to @INC - which in fact isn't desired.

How can I avoid this situation?
Babs

From: "B. Fongo" <perl@fongo.de>
> Is it recommendable to use the pragma "use lib " when installing a
> program on a server shared by many users?  Assuming my IPS did not
> install certain CPAN modules which my needs, and I decide to install
> them in my www directory. In such a scenario, putting "use lib" on my
> scripts will add my module directory to @INC - which in fact isn't
> desired.

1) not sure how do you have this setup, but the directory containing
the modules should not be accessible via web

2) having a
use lib 'something';
in a script affects @INC just for this script. Which in fact is
desired. You need to do so, otherwise the modules would not be found.

You may remove the directory from the @INC after you import the
modules with
BEGIN {shift(@INC)};
(assuming you are sure the directory was NOT present in @INC before!)
but I do not see any reason to do so.

Jenda
===== Jenda@Krynicky.cz === http://Jenda.Krynicky.cz =====
When it comes to wine, women and song, wizards are allowed
to get drunk and croon as much as they like.
-- Terry Pratchett in Sourcery

B. Fongo wrote:
> Is it recommendable to use the pragma "use lib " when installing a
> program on a server shared by many users?
> Assuming my IPS did not install certain CPAN modules which my needs,
> and I decide to install them in my www directory.
> In such a scenario, putting "use lib" on my scripts will add my module
> directory to @INC - which in fact isn't desired.

This is only an issue under mod_perl, where @INC persists across requests
and would thus be shared by multiple scripts.

Under mod_cgi, the changes made by "use lib" affect only the current
process's copy of @INC, so there's nothing to be concerned about.

>
> How can I avoid this situation?

You could try something like this if you're running under mod_perl:

use lib '/my/lib/path';
use MyModule;
no lib '/my/lib/path';