gdb on Linux w. spawn'ed threads?

[Andy Valencia]

I'm cooking a micro-web service using serverino.  I have used 
gdb, but now I've set a breakpoint in a function which the 
serverino middleware should be invoking from a worker thread.  I 
have a writeln() to verify the code's being invoked--but gdb will 
_not_ break.  I've verified a correct code address for the 
breakpoint.

Has anybody else noticed a problem with breakpoints for worker 
threads?  Or should I be looking at something else?

(Note, I can break at _Dmain and see things OK, it's just once 
the middleware has taken over that I can't seem to look at the 
running code.)