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Re: Bash arithmetic doesn't give error message on wrap.
From: |
Chet Ramey |
Subject: |
Re: Bash arithmetic doesn't give error message on wrap. |
Date: |
Sat, 28 Apr 2007 11:25:44 -0400 |
User-agent: |
Thunderbird 2.0.0.0 (Macintosh/20070326) |
Richard Neill wrote:
> Bash Version: 3.2
> Patch Level: 13
> Release Status: release
>
> Description:
> $ echo $((4000000000*4000000000)
> -2446744073709551616
>
> Repeat-By:
> Do some arithmetic in bash $((....)).
> If the numbers are out of range, the output will be wrong in
> all sorts of interesting ways. No error message is given.
>
> Fix:
> Arbitrary-precision maths would be nice. But at least, could we
> have an error message if an overflow occurs?
>
> The man page says:
> "Evaluation is done in fixed-width integers with no
> check for overflow..."
> but I'd suggest this represents a bug, not a feature.
I'm comfortable with the current behavior. POSIX requires that expressions
be evaluated according to the C standard, and that standard leaves the
treatment of integer overflow as undefined.
Chet
--
``The lyf so short, the craft so long to lerne.'' - Chaucer
Live Strong. No day but today.
Chet Ramey, ITS, CWRU chet@case.edu http://cnswww.cns.cwru.edu/~chet/
- Bash arithmetic doesn't give error message on wrap., Richard Neill, 2007/04/27
- Re: Bash arithmetic doesn't give error message on wrap.,
Chet Ramey <=
- Re: Bash arithmetic doesn't give error message on wrap., Richard Neill, 2007/04/28
- Re: Bash arithmetic doesn't give error message on wrap., Bob Proulx, 2007/04/29
- Re: Bash arithmetic doesn't give error message on wrap., Richard Neill, 2007/04/29
- Re: Bash arithmetic doesn't give error message on wrap., Andreas Schwab, 2007/04/30
- Re: Bash arithmetic doesn't give error message on wrap., Bob Proulx, 2007/04/30
- Re: Bash arithmetic doesn't give error message on wrap., Richard Neill, 2007/04/30
- Re: Bash arithmetic doesn't give error message on wrap., Paul Jarc, 2007/04/30
- Re: Bash arithmetic doesn't give error message on wrap., Andreas Schwab, 2007/04/30
- Re: Bash arithmetic doesn't give error message on wrap., Paul Jarc, 2007/04/30
- Re: Bash arithmetic doesn't give error message on wrap., Paul Jarc, 2007/04/30