Date: Fri, 25 Apr 2003 05:20:11 -0700 (PDT) From: Alexey Zelkin <phantom@FreeBSD.org.ua> To: freebsd-standards@FreeBSD.org Subject: Re: standards/51292: [PATCH] add ecvt()/fcvt()/gcvt() functions (SUSv3) Message-ID: <200304251220.h3PCKBQr075267@freefall.freebsd.org>
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The following reply was made to PR standards/51292; it has been noted by GNATS.
From: Alexey Zelkin <phantom@FreeBSD.org.ua>
To: "Sergey A. Osokin" <osa@freebsd.org.ru>
Cc: FreeBSD-gnats-submit@freebsd.org
Subject: Re: standards/51292: [PATCH] add ecvt()/fcvt()/gcvt() functions (SUSv3)
Date: Fri, 25 Apr 2003 15:19:37 +0300
hi,
On Fri, Apr 25, 2003 at 12:38:51PM +0400, Sergey A. Osokin wrote:
> > > >Number: 51292
> > > >Category: standards
> > > >Synopsis: [PATCH] add ecvt()/fcvt()/gcvt() functions (SUSv3)
> >
> > Few questions related to code:
> >
> > 1. What's a reason to have some LANG handling logic here ?
>
> Because standart says:
> The radix character is determined by the current locale.
> Follow this way: check LANG, then set locale.
First sentence is correct, but second one is wrong. radix character
is a 'property' of LC_NUMERIC locale category. So, having LANG=C
and LC_NUMERIC=ru_RU.KOI8-R should use russian locale radix character.
Actually, all these cases should be handled by setlocale() itself. And
after call to 'setlocale()' you should use lconv() to receive current
radix character.
I also would object to using of setlocale() from libc's function internally.
It's a application's problem to decide which locale to use and [fge]cvt()
should use locale previously set by application.
> > 2. Did you check correctness of dtoa()'s usage here ? It's not easy
> > and after last netlib's import it become more uneasy.
From reading of SUSv3's section related to these functions I'd suggest
following way to check a function (and maybe write a regression-test
for these funcs).
1. declare some set of floating values (more than one)
2. and try comapring result of gcvt() against of result of printf("%g").
same for others.
3. check these results against predefined values (if you'll write a
regression test program)
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