Re: signal weirdness fix

[Richard Coleman <coleman@xxxxxxxxxxxxxxx>]

> I'm now a bit less puzzled by your long message about how buggy zsh's
> signal handling is:  It's not quite as buggy as you thought, just badly
> organized and under-commented.
> 
> } Although this patch fixes some bad signal problems in zsh I still think
> } that it is a big mess and should be ceaned up.  The most important is to
> } move trap execution out of the signal handler.  We should only use libc
> } calls which are guaranteed to be reentrant on all systems.  This probably
> } means that we cannot use malloc() and stdio functions.  Preferably we
> } should use system calls only.

I agree with Zoltan here.  Zsh executes way too much code in its
signal handlers.  But fixing it is non-trivial.  And it is complicated
by the way we handle `errflag'.  I think it might be easier to change
the way errors are handled first (using setjmp, longjmp), and then
work on the signal handling code.

rc