Subject: Re: floating point negative zero in awk
To: Jason Thorpe <thorpej@shagadelic.org>
From: Aleksey Cheusov <cheusov@tut.by>
List: tech-userlevel
Date: 09/08/2007 10:48:52
> On Aug 27, 2007, at 7:53 PM, Jeremy C. Reed wrote:

 >> On Mon, 27 Aug 2007, Jason Thorpe wrote:
 >>
 >>>> 	$ echo | awk '{ print -1 * 0 }'
 >>>> 	-0
 >>>>
 >>>> Would it be OK if I commit the following patch, which ensures that
 >>>> arithmetic in awk will never yield a negative zero?
 >>>
 >>> No objection from me.  Does POSIX have anything to say about this?
 >>> What does
 >>> GNU AWK do?
 >>
 >> glacier:/opt/home/reed/book/bsdwiki$ echo | awk '{ print -1 * 0 }'
 >> -0
 >>
 >> glacier:/opt/home/reed/book/bsdwiki$ echo | gawk '{ print -1 * 0 }'
 >> 0

> Then your patch is fine with me.

JFYI

~>gawk 'BEGIN { print (-1) * 0 }'              
0
~>gawk 'BEGIN { printf "%d\n", (-1) * 0 }'     
0
~>gawk 'BEGIN { printf "%g\n", (-1.0) * 0.0 }' 
-0
~>

-- 
Best regards, Aleksey Cheusov.