From: Vincent Lefevre <vincent@vinc17.net>
To: "zsh-workers@zsh.org" <zsh-workers@zsh.org>
Subject: Re: Math expression evaluation error?
Date: Thu, 15 Jan 2015 14:41:38 +0100 [thread overview]
Message-ID: <20150115134138.GB30651@ypig.lip.ens-lyon.fr> (raw)
In-Reply-To: <20150115133421.GA30651@ypig.lip.ens-lyon.fr>
On 2015-01-15 14:34:21 +0100, Vincent Lefevre wrote:
> > > But POSIX doesn't specify the arithmetic evaluation on expressions
> > > other than signed long integer arithmetic. An implementation that
> > > decides that $((1.0/2)) gives 17 "as an extension" could still be
> > > conforming.
> >
> > Nope, it cannot ever be conforming. POSIX does this by saying that
> > semantic of operation is the same as in C,
>
> Only for what it specifies.
BTW, note also that the ISO C standard doesn't specify the accuracy,
unless Annex F (IEEE 754) is supported (which is not required by
POSIX). So, even if the shell claims to implement floating-point
arithmetic, any floating-point number as the result of $((1.0/2))
would be conforming.
--
Vincent Lefèvre <vincent@vinc17.net> - Web: <https://www.vinc17.net/>
100% accessible validated (X)HTML - Blog: <https://www.vinc17.net/blog/>
Work: CR INRIA - computer arithmetic / AriC project (LIP, ENS-Lyon)
next prev parent reply other threads:[~2015-01-15 13:41 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-09 19:46 jdh
2015-01-09 20:15 ` Peter Stephenson
2015-01-09 21:40 ` jdh
2015-01-09 22:19 ` Ray Andrews
2015-01-09 23:06 ` Lawrence Velázquez
2015-01-09 23:52 ` Ray Andrews
2015-01-10 0:25 ` Bart Schaefer
2015-01-10 7:27 ` Ray Andrews
2015-01-10 16:53 ` Bart Schaefer
2015-01-10 18:48 ` Ray Andrews
2015-01-10 19:14 ` Bart Schaefer
2015-01-10 22:21 ` Ray Andrews
2015-01-11 1:51 ` Bart Schaefer
2015-01-11 5:10 ` Ray Andrews
2015-01-12 9:17 ` Vincent Lefevre
2015-01-12 16:18 ` ZyX
2015-01-13 16:00 ` Vincent Lefevre
2015-01-13 23:03 ` ZyX
2015-01-14 14:47 ` Vincent Lefevre
2015-01-14 21:37 ` ZyX
2015-01-15 13:34 ` Vincent Lefevre
2015-01-15 13:41 ` Vincent Lefevre [this message]
2015-01-15 18:32 ` ZyX
2015-01-15 21:57 ` Bart Schaefer
2015-01-09 22:40 ` Peter Stephenson
2015-01-12 10:55 ` Peter Stephenson
2015-01-14 15:02 ` Vincent Lefevre
2015-01-14 15:38 ` Peter Stephenson
2015-01-15 14:58 ` Peter Stephenson
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