DllCall is a powerful way to use AutoIt code to run functions that were created in other languages and are stored in shared libraries outside of AutoIt.  With DllCall, you can call Windows APIs directly, execute pieces of code that shipped with another vendor's product, and pass information between that code and your own script. However, DllCall is intended for the advanced user who is already familiar with how that stuff works.  That definitely isn't me, and I find the process of converting var