I want to use data from one of my FM program to use it on my other FM program to make some calculation. I want to use the data while both programs are open and running so I can have an active link between both program.
go to 'define database', tab 'relationship,. Hit the '+' button (down left) , add a new FileMaker source (Your other file..), define matching elements (or 'X' for all) - and You can access data in file A from file B
You'll find mote details about this in the help/manual (i.e. FileMaker Pro help, 'define relationship')
Retrieving data ...