Assuming I can solve the header/library issues, what can you tell me about using writeline() , writelinereadline(), etc?

I am guessing that I can pass strings (via the USB port) back and forth between the programs that reside on the two boards, and that I can parse the strings within each program.

First, can I have multiple threads per board? That is, let's say I have two boards, A nd B. Should I use a parser for A, and a parser for B, and then use those to modify global variables (such as flags, variables, etc), and have a "main program" thread for each board (so I'd have 4 threads total)?

As an alternate approach, would it be easier just to use the RS 232 port on each board to do coordination?

Thanks