The .info file and other files
I'm writing a module in Drupal 7 with both classes and functions. I want to split these over several files and call one function from another file. I notice that some files need to be declared in the .info file and others not. I'm having problems with 'seeing' functions whose definition resides in other files when called from another file.
What are the rules here? Can someone point me in the direction of some good documentation?
Thanks in advance.