I am using Lite C and cannot use Legacy C. I am trying to manage coroutine function during a "wait()" command. A command like "if(check != 2){return:}" at the beginning of a function does not seem to work. Any ideas please.

the check variable has to be a global var in your example.

better solution:
use "proc_kill(4);" at the beginning of the cofunction. Read the manual entry about that function.

Thank you for your reply. I have tried proc_kill(4). Unfortunately, it stops all the functions and I cannot read a keypress. There is no "my" or "you" as the program is for reaction time testing and not a "game". I suppose I could "pretend" a game and try proc_kill but I am not sure how to do that.