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	Fri, 19 Sep 1997 13:19:29 +0200 (CEST)
To: Bruce Evans <bde@zeta.org.au>
cc: atrens@nortel.ca, freebsd-bugs@FreeBSD.ORG, gram@cdsec.com, grog@lemis.com,
        hackers@FreeBSD.ORG, peter@spinner.dialix.com.au
Subject: Re: Bug in malloc/free 
In-reply-to: Your message of "Fri, 19 Sep 1997 20:24:02 +1000."
             <199709191024.UAA12065@godzilla.zeta.org.au> 
Date: Fri, 19 Sep 1997 13:19:29 +0200
Message-ID: <13341.874667969@critter.freebsd.dk>
From: Poul-Henning Kamp <phk@critter.freebsd.dk>
Sender: owner-freebsd-bugs@FreeBSD.ORG
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In message <199709191024.UAA12065@godzilla.zeta.org.au>, Bruce Evans writes:
>>>STDC only allows operations on auto variables and assignment to static
>>>variables of type sig_atomic_t.  We aren't STDC conformant either.
>                   ^volatile
>>>Operations on auto floating point variables may corrupt the floating
>>>point state.  This isn't a problem in practice, since nothing useful
>>>can be done using only auto floating point variables.
>>
>>You could calculate pi... :-)
>
>I was going to say that this is more useless than usual since there is
>no way to output the results.  However, I think the following works:
>
>	volatile sig_atomic_t encoded_results[MANY];
>
>	void handler(int s) {
>		int i;
>
>		for (i = 0; i < MANY; ++i)
>			encoded_results[i] = bit_of_pi(i) == 0 ? 1 : 2;
>	}
>
>There is no way to calculate only a few bits per call since there is no
>way to keep track of state.

Wrong.  A signal handler can have a private static variable.

:-)

--
Poul-Henning Kamp             FreeBSD coreteam member
phk@FreeBSD.ORG               "Real hackers run -current on their laptop."