Also, I need to have a central repository for the custom libraries.

Sure, but only custom libraries should be there. There should not, for example, be copies of core modules in there. That would create headaches.

I have to reference some custom libraries that were written for 5.005_03

If the custom libraries will also run under more recent versions, I don't see the problem. If they won't, then of course they have to be fixed so that they will.

So,when I tried running the same code on Solaris, it barfed because of the Perl 5.6.1 system is expecting Perl 5.6.1 versions of IO to be in PERL5LIB

Yes, that's what it should expect. If that system has 5.6.1, then its PERL5LIB should be the one for 5.6.1 also. That's basic consistency. If you are changing PERL5LIB to point to a central directory, then all the systems using that directory need to have the same version of Perl. Otherwise, if they have different versions of Perl, they must also have different versions of PERL5LIB.

what would the best practice be?

The best practice would be to write your code so that it doesn't matter which version of Perl it runs under, simply by not relying on version-specific hacks.

I still don't understand your problem with modules; for any given module you are trying to use, there are three possibilities: it will run fine under either version of Perl, it won't run at all under some versions, or a different version of it is needed depending on the Perl version. In the first (ideal) case, there should be no problem. In the second case, it should be obvious that you can't use that module. In the third case, you must install the right version of the module on each system for the version of Perl that is there.

In no event should any of your code ever be looking for specific versions of a module. Write your code generally, without version-specific hacks, so that any (supported) version of the module will just work.

(If the module changed its API between versions, you should either not use that module (my first inclination) or if you absolutely must use it write a wrapper module so that you don't have to use it directly; install the correct version of the wrapper module on each system for the version of the wrapped module that is there. All versions of the wrapper module should present the same API to the rest of your code.)

Some of my assumptions may be way off base; I had a hard time following your description of your problem, but as best I understand it, it _sounds_ like the custom modules aren't really your problem, but some core modules that you (or the custom modules) use. It sounds from some parts of your explanation like some installations are getting versions of the core modules that are wrong for the version of Perl and/or for eachother. This implies that someone at your site has messed with the core modules in an inappropriate way. It's hard to be more specific without knowing more details about your setup, except to say that each installation of Perl should have its own installation of the core modules, and any custom modules that are to be shared across multiple versions of Perl must be able to work correctly with whichever versions of Perl (and thus the core modules) they happen to get.

---

for(unpack("C*",'GGGG?GGGG?O__\?WccW?{GCw?Wcc{?Wcc~?Wcc{?~cc'
.'W?')){$j=$_-63;++$a;for$p(0..7){$h[$p][$a]=$j%2;$j/=2}}for$
p(0..7){for$a(1..45){$_=($h[$p-1][$a])?'#':' ';print}print$/}
[download]