I find it useful to think of module variables as if they were C++ private member variables. Consider the "module" to be a class, and the functions that interact with the member variables are methods.

The whole idea is that the methods expose an interface and the class hides the inner workings.

While the overhead for a call to

ModuleGetFoo()

is more expensive than using an externed global, it's probably a reasonable expense in all but the stingiest of programs.

-a