In an earlier post I asked about require, if using it multiple times would slow things down. As merlyn explains, require is just a hash look up.

Going back to some of my code, I removed some use directives and put them as require directives inside subs and methods. This sped things up a lot for some procedures. Where I have used web apps, this has helped tremendously.

The next question I have is about the 'use' statement.

My basic question is do multiple use statements cause as little expense as multiple require statements? I know that use runs at compile time where require at run time, does this relate to the answer, how?

Long version of my question:

What if I three packages; A, B1, and B2. All three packages 'use' C. A imports B1 and B2. (pseudocode) 

package A;
use C;
use B1;
use B2;
1;

package B1;
use C;
1;

package B2;
use C;
1;

[download]

Does package C get loaded 3 times?
If C exports into into all three namespaces, does it slow things down?
(Should I be looking into coding C instead, for this kind of nitpicking?)

This is a loose example, what I am concerned with are more intricate dependencies, bigger things.

In reply to Do multiple use statements across module dependency hierarchies require as little expense as multiple require statements? by leocharre

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