include " <filename> "
When the compiler reaches an Include statement, it continues compilation at the included file (usually *.INC) and when it's done resumes compiling from the Include statement. In other words, these files contain code that gets inserted at the place of inclusion.
This is very handy for breaking up your code into pieces. The handling of video in one include file, audio in another, game logic in another, etc. This makes code more maintainable and understandable; moreover it makes code reusable. The video handling include file you made for one game can be used for another game (if it was coded in a generic fashion) without spitting through the whole sourcecode of the first game.
Also headers can be used to import DLLs and possibly give a little more functionality to that DLL. For example Network.DLL uses a .INC header file to assure the DLL is only imported once during compilation and provides a little more functionality.
// The code in "bar.inc" will be processed first: include "bar.inc" import "mod_say" Process Main() Private int barcode; Begin barcode = bar(); say(barcode); End
import "mod_rand" Function int bar() Begin return rand(0,10); End