Will a process run independent of the main once it is called from the
main?

What I want to do is to check for a condition 'continuously' and
basically, whenever this condition is true, the `main' should
terminate. But I don't want it the case where I call on this process or
function at the beginning of the loop or at the end or any other
pattern as such.

Is there a way of coding so that the process is continuously running
with the others tasks running simultaneously in the background or vice
versa?

Any help is greatly appreciated!