[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20250408222526.GA2724612@port70.net>
Date: Wed, 9 Apr 2025 00:25:26 +0200
From: Szabolcs Nagy <nsz@...t70.net>
To: Lénárd Szolnoki <cpp@...ardszolnoki.com>
Cc: musl@...ts.openwall.com
Subject: Re: strtod doesn't set errno to ERANGE for slightly
out-of-range hex float
* Lénárd Szolnoki <cpp@...ardszolnoki.com> [2025-03-24 10:55:36 +0000]:
> Hi,
>
> #include <stdlib.h>
> #include <assert.h>
> #include <errno.h>
>
> int main() {
> const char* const input = "0x1.fffffffffffff8p+1023";
> double ret = strtod(input, NULL);
> assert(errno == ERANGE);
> }
>
> The input is slightly out of range, DBL_MAX is 1.fffffffffffffp+1023 (one
> fewer binary 1 in the mantissa).
>
> The assert fails with musl libc, passes with glibc.
this looks valid (might depend on long double
representation).
the overflow threshold is not calculated precisely
for the hexfloat case. __floatscan returns an in
range long double value that is rounded to inf by
strtod, but there is no overflow check there.
i guess hexfloat overflow check should be fixed.
>
> musl version: 1.2.5 (as shipped in Debian sid)
>
> Regards,
> Lénárd Szolnoki
Powered by blists - more mailing lists
Confused about mailing lists and their use?
Read about mailing lists on Wikipedia
and check out these
guidelines on proper formatting of your messages.
