From: Gabriel Ravier <firstname.lastname@example.org>
To: email@example.com, Joakim Sindholt <firstname.lastname@example.org>
Subject: Re: [musl] ecvt(0, 0, ...) is broken
Date: Tue, 6 Sep 2022 14:21:52 +0200 [thread overview]
Message-ID: <email@example.com> (raw)
On 9/6/22 14:13, Joakim Sindholt wrote:
> On Tue, 6 Sep 2022 12:12:48 +0200, Gabriel Ravier <firstname.lastname@example.org> wrote:
>> Executing ecvt(0, 0, &decpt, &sign) results in musl returning
>> This seems highly likely to be a bug considering that glibc returns ""
>> and I see no plausible reasoning for musl's behavior that could be
>> justified by the standard.
> POSIX.1-2001 said:
>> The ecvt() function shall convert value to a null-terminated string of
>> ndigit digits (where ndigit is reduced to an unspecified limit
>> determined by the precision of a double) and return a pointer to the
>> string. The high-order digit shall be non-zero, unless the value is 0.
> The first part would imply that ndigit=0 should return the string "" but
> the second part makes no provision for a zero-digit-long string.
> I would say ndigit=0 is UB.
Wouldn't that then mean that any request call of fcvt with a small
ndigits but very small value that isn't 0, as in my previous email,
would also be UB (since if my logic is correct, the string cannot start
with a 0 but it also cannot start with any other value, which forces it
to be empty) ? That seems rather excessive...
next prev parent reply other threads:[~2022-09-06 12:22 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-06 9:27 [musl] Bug report: fcvt seems dysfunctional Gabriel Ravier
2022-09-06 10:12 ` [musl] ecvt(0, 0, ...) is broken Gabriel Ravier
2022-09-06 12:13 ` Joakim Sindholt
2022-09-06 12:21 ` Gabriel Ravier [this message]
2022-09-06 14:17 ` Rich Felker
2022-09-06 18:48 ` Markus Wichmann
2022-09-06 19:19 ` Rich Felker
2022-09-07 3:39 ` Markus Wichmann
2022-09-07 3:51 ` Jeffrey Walton
2022-09-07 13:44 ` Rich Felker
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