installing multiple versions of same module

goonfest has asked for the wisdom of the Perl Monks concerning the following question:

Before I try it, I want to see if anyone has any insights.

I want to install version 2.0 of a perl module into a local directory. The concern is that version 1.0 of the same module already exists in the main PERL directory that I do NOT have write-access to.

Of course, I could always contact the system admin to upgrade the module, but I reckon it would not be high on his priority list.

In my script, I am using a standard header subroutine to pull in modules from both my local directory and the main PERL dir.

I am using a "use lib" statement for each directory, thus, what will @INC contain if it sees the same module name twice?

Are multiple "use lib" statments somehow prioritized, that is, will the last imported instance of a module overwrite any of those previously imported, or vice-versa?

I'm sure this same issue will arise again in the future. Any other ideas(not involving the sys admin) on what I can do?

Is their great risk of crashing anything? Mind you, I am doing this at work.

"Be proud, be a Goon"

Comment on installing multiple versions of same module

Replies are listed 'Best First'.
Re: installing multiple versions of same module by jsprat (Curate) on Apr 26, 2002 at 16:42 UTC
When you `use lib '/path/to/lib'` it is unshifted onto the front of @INC, so the directory you added at runtime will take precedence over the built-in @INC. HTH	[reply] [d/l]
Re: Re: installing multiple versions of same module by jreades (Friar) on Apr 26, 2002 at 16:48 UTC
You could also use a BEGIN block, I believe: `BEGIN { unshift @INC, /path/to/other/libs; }` [download]	[reply] [d/l]
Re: installing multiple versions of same module by TheHobbit (Pilgrim) on Apr 26, 2002 at 18:12 UTC
Hi, A better solution (at least on Unix) would be to define the `PERL5LIB` shell variable. See the ENVIRONMENT section in the perlrun man page. Cheers Leo TheHobbit	[reply] [d/l]
Re: Re: installing multiple versions of same module by jsprat (Curate) on Apr 26, 2002 at 18:46 UTC
For certain definitions of the word better ;-) Seriously, this does work, and it works on Windows too. Just not all the time. If you're the only one running the script, it will work fine. If someone else is running your script, he/she may not have the same environment that you do. Rather than force everyone to have the same environment variable set, I'd prefer giving them access to my module directory. Let the script handle the rest.	[reply]


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