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Date: Tue, 8 Apr 2003 12:51:12 +0400
From: Alex Semenyaka <alexs@ratmir.ru>
To: freebsd-standards@freebsd.org
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Subject: /bin/sh arithmetics: BIG NUMBERS
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Collegues,

I need your opinion. Several days ago I've send to -hackers mailing list a
patch for /bin/sh which introduce 64-bit arithmetic operations instead of
32-bit ones we have now. There were now principal objections there but
Giorgos Keramidas <keramida@freebsd.org> adviced me to ask here about the
FreeBSD's standards compliance of this. I hope that it IS ok withem but
I want to be absolutely sure.

Argumentation "pro":

1) POSIX and SUSv3 _require_ at least long type for integers in the shell, and
   explicitly _allow_ to use integer in the range beyond the long type range.
   SUSv2 _requires_ long and _allows_ extensions as well (but there are no
   explicit words about wider range as in SUSv3). It is the theoretical aspect.
2) ksh, zsh and bash handle longer integers properly. The last two have
   64-bit arithmetics and first one has float inside. That is the compatibility
   aspect.
3) These days we have a lot of 64-bit stuff in the system: from ipfw counters
   to file sizes. Moreover we really have such big numbers in everyday FreeBSD
   usage. But now /bin/sh silently produce just wrong results dealing with
   such numbers due to overflow. So old scripts which worked from 1997 or such
   now can produce meaningless results and it will not be even noticed.
   I can suggest to write new ones with bash or zsh but some people continue
   to use their old stuff (don't touch while works, you know). So it IS better
   to change our basic shell and extend it's abilities. That is the practical
   aspect.
   
Any "contras"?

								SY, Alex