To clarify Corion's point: use() is expanded to this:

BEGIN { require Module; import Module LIST; }
[download]

So unlike a plain require() (which does only load the file once), use() calls import() each time, which is responsible for making the functions available in your code where you need it.

"Turning your required file into a module" means giving it an import() routine that makes functions available in whatever package you happen to be in when use() is called. That is typically done with Exporter. use() also takes a bareword -- not a file name, so you have to ensure the file name and barewords are in sync.

So, for example, in the file "utility.pm":

package utility; # package "utility" is sought as "utility.pm"

use base 'Exporter'; # inherit the "import" sub

@utility::EXPORT = qw( wibble wobble ); # tell "import" what subs to e
+xport

sub wibble { print "wibble" }

sub wobble { print "wobble" }

1; # modules must return a true value
[download]