Using BLOCK with user input polling

[RyanBurnside]

I'm currently working on a paint program and it's going well enough.
I call BLOCK in my program once per loop to allow other programs to do their things while the paint program is running.

The problem comes in when BLOCK returns control to the OS and the underlying windows start getting keyboard input once more. The issue makes sense but perhaps I don't know how to structure a self updating program that needs to also absorb all keystrokes for interaction while running. For example holding the < and > keys adjust brush size but between BLOCKs those characters eco into the EXEC below.

What is the correct(?) way to structure a Medley program that needs to not take over the system but also absorb keystrokes?

[pamoroso]

An (untested) approach that comes to mind is to grab the TTY while the program is doing work and release the TTY just before blocking.

[pamoroso]

This section of the IRM may help: Switching the TTY Process.

[RyanBurnside]

I'll give it a shot, thanks!