Application Programming Interface (API) is a set of subroutine definitions, protocols, and tools for building application software. In general terms, it is a set of clearly defined methods of communication between various software components.
Due to a new project I'm getting involved inside %Installer stuff deeper than ever I'd be happy to. Most of it was pretty easy to get, thanks to documentation, articles and SAMPLES example, while I can't dig good solution for one problem.
By update