UCB signals in ATT universe

[Cris Letourneau]

We have a couple of programs here that are compiled in and run in the
att universe that are getting a signal 16.  According to the comment
in /usr/.attinclude/sys/signal.h this is a BSD unique signal. 
The comment says "urgent condition on IO channel".  

I have two questions - what is causing this urgent condition? 
		     - how can we get a ucb signal in an att-compiled
		       program running in and att universe.

Any help would be greatly appreciated.

Thanks,

Cris
cas at ctt.bellcore.com