Efficiently loading modules

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

Which below is generally more efficient considering that the directory with the modules has perhaps 15-20 custom modules? And also, are the used modules loaded dynamically or is everything in the 'lib' directory compiled at runtime?

use lib '/path/to/modules';
use CustomMod1;
use CustomMod2; ...etc.
-or-

require '/path/to/modules/CustomMod1.pm';
require '/path/to/modules/CustomMod2.pm';
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And as a side question, are modules more efficient than libraries (if so why?) Thanks from a novice!

Comment on Efficiently loading modules Download Code

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Re: Efficiently loading modules by arturo (Vicar) on May 10, 2001 at 19:25 UTC
`use` and `require` do different things, so there really is no comparison here. `use` is a compile-time directive, while `require` is a run-time directive (happens after the script starts executing). In addition, `use Foo` imports all of the symbols (variables, subroutines, etc.) that the module exports, while `require` doesn't. I doubt there's that much of a speed difference when you add in the code that would make the second method do what the first does. The first is also way easier to maintain. Your best optimizations in this area come with using only the modules you need and importing only the symbols you need. HTH! `perl -e 'print "How sweet does a rose smell? "; chomp $n = <STDIN>; $r +ose = "smells sweet to degree $n"; other_name = rose; print "$other +_name\n"'` [download]	[reply] [d/l] [select]
Re: Efficiently loading modules by merlyn (Sage) on May 10, 2001 at 19:25 UTC
The differences in speed will be down in the noise level, and the `use` permits prototyped subroutines to have an influence on the following compilation. So all other things being equal, use the `use`, luke! -- Randal L. Schwartz, Perl hacker	[reply]
Re: Efficiently loading modules by petdance (Parson) on May 10, 2001 at 19:53 UTC
`#include <standard_efficiency_screed.h>` Does it matter which is "more efficient"? Are you having a speed problem? Have you run anything thru Benchmark? Dijkstra says "Premature optimization is the root of all evil". My corrollary is that "'Unnecessary' is, by definition, premature." xoxo, Andy %_=split/;/,".;;n;u;e;ot;t;her;c; ". # Andy Lester 'Perl ;@; a;a;j;m;er;y;t;p;n;d;s;o;'. # http://petdance.com "hack";print map delete$_{$_},split//,q< andy@petdance.com >	[reply]