don't do long jumps in signal handlers

[Donn Seeley]

	From: wls at astrovax.UUCP (William L. Sebok)

	In my opinion, if [Berkeley] didn't want signals to abort
	terminal reads they should have provided an explicit i/o abort
	function that could be called from the signal handler.

I wrote such a function and posted it to the net some time ago...  It
was a bit ugly but it worked.

I understand that Berkeley may be considering providing a facility for
4.3 BSD that would allow you to specify that a particular signal can
interrupt a slow system call.  This might be done by changing the
on_stack member in the sigvec structure to be a generalized flags
variable, and inventing a flag that would tell the system, 'Don't
restart system calls when you see this signal.'

To quote a recent version of the signal.h file at Berkeley,

	'isn't compatibility wonderful!'?

Donn Seeley    University of Utah CS Dept    donn at utah-cs.arpa
40 46' 6"N 111 50' 34"W    (801) 581-5668    decvax!utah-cs!donn