Question

I’ve always wondered this. I have a habit of always adding

use strict;
use warnings;
use Data::Dumper;

to the top of every script I write. Does this add overhead if I don’t even use the Dumper function? Also, in most cases Data::Dumper was called earlier in another package but I need it in this package so I include it again. In this case does it produce additional overhead?

Answer 1

If they have BEGIN blocks or import routines, then yes, it always adds overhead. Also any mainline code will be executed eventually and any INIT, CHECK, and END blocks will also execute.

The only way it won’t add overhead is if the module expects use to be nothing more than like require. (Of course, require also runs everything except the import routine, but that’s why I mentioned the view from the use-d module. It “expects” to be nothing but a simple require.)

If you want to retain that line, for some reason, just comment it out. In development, it’s okay to have modules that you don’t use. In QA or production, that’s a mistake, IMO.