[development] module_exists vs. functions_exists?

[Moshe Weitzman]

> Come Drupal 7, you'll want to use drupal_function_exists() specifically so
> that it can lazy-load the function if needed.  I suppose that's a strike in
> favor of using function_exists() for now so that your logic is already setup
> for that.

Right ... For D6 and below, module_invoke() does the if
(function_exists()) for you. Some people prefer that pattern.