don't do long jumps in signal handlers

[William L. Sebok]

> I think the real problem is that UNIX allows one to catch signals at all.
> Given that we don't have cheap processes a la Thoth, catching signals is a
> necessary evil but signal handlers should be kept simple and in particular
> should avoid using longjmp (if you have ever read and understood the source,
> you won't want to use longjmp).

Unfortunately if you wan't to interrupt a 4.2 read() from a terminal you
have to do longjmp (or worse).

In my opinion, if they 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.
-- 
Bill Sebok			Princeton University, Astrophysics
{allegra,akgua,burl,cbosgd,decvax,ihnp4,noao,princeton,vax135}!astrovax!wls