Re: standards on SIGFPE for divide by zero

[Steven Bellovin <smb%cs.columbia.edu@localhost>]

On Mar 3, 2011, at 2:12 18AM, Ignatios Souvatzis wrote:

> On Wed, Mar 02, 2011 at 02:59:32PM -0500, Thor Lancelot Simon wrote:
> 
>> You want the program to get a floating-point-exception signal on a bad
>> integer divide?
> 
> Uh, it's been a generic arithmetic error signal for a long time, like
> ENOTTY complaining about generic wrong-type-of-file-descriptor situations.
> I was surprised by that a couple of years ago.
> 
> SUSV3 defines:
> 
> SIGFPE        A Erroneous arithmetic operation.
> ...
> SIGFPE        FPE_INTDIV Integer divide by zero.
>       FPE_INTOVF Integer overflow.
>       FPE_FLTDIV Floating-point divide by zero.
>       (...)
> 
> Now, if the hardware in question can't create SIGFPE on integer divide,
> I don't think we should torture the compiler into simulating it.
> 
What does the C standard say?  Is the exception required?


                --Steve Bellovin, http://www.cs.columbia.edu/~smb