This file is used with some of the targets in the makefile, like distcheck, distclean, dist, etc. This the skeleton module file. For XS modules, the Dynaloader, and boostrap areas are the importiant parts. It will contain the functions and methods that are implemented in C, and the glue code so they can be called from Perl. Verifying the code can help point out platform dependencies and platform differences when other users attempt to build your software.
Unit tests are also useful for helping test and debug code.
We add a clear method, to clear all of these fields. This is where the actual implementation will go. We create the XS functions and give them the same names as the C functions they'll be calling. XS functions have to be written with a specific format for the XS compiler to recognize them. The return value must be on it's own line.