>Here is the situation:
>My main application is calling another program compiled in .APP program.
>
>

>DO MyAddOn.app with "XYZ"
>

>
>In the project MyAddOn.app I use some functions that are defined in the main/calling application. And even though when creating MyAddOn.app VFP compiler complains that a function is not found, the function works in MyAddOn.app. This tells me that the .APP program can use any function or any public variable defined in the main/calling application. Correct?
>
>My question is, when I open the calling/main application (before .app is called), does it automatically pulls the entire .APP in the memory of the PC?

Not before you call your .APP, but after you call the .APP, all functions/procedures, etc in your .APP file are now in memory and available to called.