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Mail Archives: djgpp-workers/2003/08/22/13:31:15

From: <ams AT ludd DOT luth DOT se>
Message-Id: <200308221711.h7MHBeCL021198@speedy.ludd.luth.se>
Subject: Re: Arithmetic Exceptions in C99
In-Reply-To: <1d9.f96c51c.2c767308@aol.com> "from Kbwms@aol.com at Aug 21, 2003
03:10:00 pm"
To: djgpp-workers AT delorie DOT com
Date: Fri, 22 Aug 2003 19:11:40 +0200 (CEST)
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According to Kbwms AT aol DOT com:
> In a recent communication with Eli Zaretskii, the problem of raising 
> arithmetic exceptions, as described in C99, arose.  His latest thoughts are appended 
> to this email as a postscript.  Paragraph F.9 of C99 is attached to this email 
> for those who do not have C99 on their system.

Is that from the real C99 or from the draft you refer to below as C99?

> In C99, functions nearbyint are specifically prohibited from endangering the 
> setting of the inexact exception.  I am not aware of any other functions where 
> a similar restriction exists.  So, what do we do about exceptions?  Except 

I think they specifically point out that because if you round you are
making the result inexact (so a inexact exception is plausible), but
as you are asking for rounding you should not get that exception in
this case.

> For those who have been pining for a copy of C99, here is a link:
> 
> <A HREF="http://anubis.dkuug.dk/JTC1/SC22/WG14/www/docs/n869/ ">http://anubis.dkuug.dk/JTC1/SC22/WG14/www/docs/n869/</A> 

That isn't C99. That's a draft. According to comp.std.c real changes
were made after that draft. You shouldn't advertise it as C99. (But
it's the best that is freely available.)

> In a message dated 8/21/2003 9:57:50 AM Eastern Standard Time, 
> eliz AT elta DOT co DOT il writes:
> > The main issue, as far as I'm concerned, is this: when C99 says
> > ``raises such-and-such exception'', does that mean that we need to
> > actually trigger a SIGFPE, or merely that the appropriate bit in
> > fexcept_t should be set?

It sure sounds like SIGFPE should be triggered. How is setting a bit
somewhere "raising an exception"?


Right,

						MartinS

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