Code for device only

I know that somewhere I've seen a snippet of code for separating out lines in a program that are for the device only. However, I can't find it again whatever search term I use.

Would some kind person please point me in the right direction?

Many thanks.

Caravelle

I guess you mean:

I guess I do. I spent 45 minutes looking for it.

I have a program which accesses file locations on the device, and to test it on the desktop I need to provide alternative file locations.

Many thanks

Caravelle