How do I make private functions in a Perl module?

Question

I am working on a little Perl module and for some reason I had the test driver script that was using my new module call one of the functions that I thought would be private,

Answer 1

From perldoc perltoot (about a quarter way through the document):

Perl doesn't impose restrictions on who gets to use which methods. The public-versus-private distinction is by convention, not syntax. (Well, unless you use the Alias module described below in "Data Members as Variables".) Occasionally you'll see method names beginning or ending with an underscore or two. This marking is a convention indicating that the methods are private to that class alone and sometimes to its closest acquaintances, its immediate subclasses. But this distinction is not enforced by Perl itself. It's up to the programmer to behave.

Therefore, I recommend you put an underscore or two at the beginning of your "private" methods to help dissuade usage.