Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!sun-barr!cs.utexas.edu!wuarchive!usc!jarthur!uunet!tdatirv!sarima
From: sarima@tdatirv.UUCP (Stanley Friesen)
Newsgroups: comp.lang.c
Subject: Re: longjmp out of signal handler (was Re: alloca() portability)
Message-ID: <67@tdatirv.UUCP>
Date: 22 Nov 90 01:27:03 GMT
References: <14377@smoke.brl.mil> <9122@ncar.ucar.edu> <27537@mimsy.umd.edu> <1990Nov09.233527.7489@chinet.chi.il.us> <27608@mimsy.umd.edu> <15@christmas.UUCP> <1990Nov16.181436.21736@zoo.toronto.edu>
Reply-To: sarima@tdatirv.UUCP (Stanley Friesen)
Organization: Teradata Corp., Irvine
Lines: 18

In article <1990Nov16.181436.21736@zoo.toronto.edu> henry@zoo.toronto.edu (Henry Spencer) writes:
>In case Chris doesn't have paragraphs to spare right now, here's a few
>sentences. :-)  It is extremely difficult to guarantee that anything
>will work portably in signal handlers, because the stranger C environments
>put bizarre restrictions on them due to difficulties with calling conventions
>and the like.

Just to emphasize this point, I have recently come across a real implementation
where such a restriction exists.

I am currently learning the library interface to AmigaDOS, and its
implementation of 'signals' totally prohibits longjumps out of the handler.
This is due to several factors - mostly involving system resource handling
and task scheduling. (Get this, by default the handler is activated in
*supervisor* mode!! You really want to long jump out of that!?!?)
-- 
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uunet!tdatirv!sarima				(Stanley Friesen)