Pass value between 2 Auotit compiled applications

How I can pass a value or variable between 2 application that both have been compiled with AutoIt?

Is "Environment Variables" a good idea? or there is another way.

aslo i don't want to do this by registry keys or a file or folder flag.

And if "Environment Variables" is a good idea, how i can create or call or use this Variables in AutoIt?

Thanks for any attention.