Subject: Re: SIGFPE?
To: Robert Elz <kre@munnari.OZ.AU>
From: Richard Rauch <rauch@eecs.ukans.edu>
List: netbsd-help
Date: 05/02/2001 06:04:11
 [...]
>   | generic to all ports, however, and so I'm posting to this list rather than
>   | to port-i386.)
> 
> No, it is generic to ports with ieee floating point support, but not to
> others.
> 
> ieee float specifies that (floating) x/0 is not to raise an exception,
 [...]
> Thus, you get no SIGFPE from the division.   You might get one later
> from attempting to operate upon the result (perhaps - depends upon the
> operation).

I didn't know that IEEE specified that.  Thanks.


> Integer divide by 0 generates SIGFPE as it isn't subject to the ieee
 [...]
>   |  (b) Inasmuch as SIGFPE seems to be used, it is applied to integer
>   |      arithmetic, rather than to floating point arithmetic.
> 
> It is used for all arithmetic exceptions.   The name comes form the (kind of
 [...]

So this is a documentation error?  (Again, signal(7) simply explains
SIGFPE as a floating point exception.  From what you say, this is
technically correct for some systems, but a little obscure even there.  
In general, it seems to be at best misleading.)


  "I probably don't know what I'm talking about." --rauch@eecs.ukans.edu