How does drupal choose which function to process the submit form?

Question

I'm really confused, can someone clarify this?

Answer 1

Check the entries for “Validating Forms” and “Submitting Forms” in the Forms API Quick Start Guide - by default, Drupal will look for a function named [form_id]_submit , but this is only the default behavior. You can override this (or add more than one callback) by placing the callback function names in the #submit attribute of the #submit declaration (see http://api.drupal.org/api/drupal/developer--topics--forms_api_reference.html / 6 # submit-prop ).