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From: rbj@uunet.UU.NET (Root Boy Jim)
Newsgroups: comp.unix.wizards
Subject: Re: What is sigcleanup?
Message-ID: <119782@uunet.UU.NET>
Date: 25 Jan 91 00:38:21 GMT
References: <1991Jan22.153802.9869@daimi.aau.dk>
Organization: UUNET Communications Services, Falls Church, VA
Lines: 29

In article <1991Jan22.153802.9869@daimi.aau.dk> kaja@daimi.aau.dk (Kaja P. Christiansen) writes:
>What is "sigcleanup" doing?

I dunno for sure, but I'll hazard a guess. It could be a mutation of
4.3BSD's sigreturn call with new bells and whistles. RTFM sez
"sigreturn allows users to atomicly unmask, switch stacks, and
return from a signal context". Since signals are more complex
than they used to be, s system call is required to exit from
them as well as to enter them. When a signal handler returns,
it executes what is known as the signal trampoline code, which
actually calls sigreturn. Setjmp/longjmp have been extended to
save and restore the signal mask as well. However, _setjmp/_longjmp
exist for speedier execution when signals are involved.

Now sing with me to the tune of a Beatles song:

	We all live in a signal trampoline,
	A signal trampoline, a signal trampoline!

>Kaja P. Christiansen                     Computer Science Department
>(kpchristiansen@daimi.aau.dk)            Aarhus University 
>Phone: +45 86 12 71 88                   Ny Munkegade 116,
>Fax:   +45 86 13 57 25                   DK-8000 Aarhus C., Denmark 


-- 

	Root Boy Jim Cottrell <rbj@uunet.uu.net>
	Close the gap of the dark year in between