To quote David R. Butenhof "It is always best to avoid using signals in conjunction with threads. When signals and threads meet, beware"[1]

I'd rather not have to handle signals. I'm sure we can come up with another way that would work just as well - how about a named pipe which uses exactly the same commands as the serial port? (Not that I'm volunteering to write it anytime soon!)

[1] Programming with POSIX Threads, David R. Butenhof, Addison Wesley. section 6.6.

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Mike Crowe
I may not be speaking on behalf of empeg above :-)