From: Szabolcs Nagy <nsz@port70.net>
To: musl@lists.openwall.com
Subject: Re: Bug report: strtod drops LSB
Date: Wed, 25 Sep 2019 17:06:32 +0200 [thread overview]
Message-ID: <20190925150632.GL22009@port70.net> (raw)
In-Reply-To: <ca099df7-a6a2-4c08-9a80-0502a16d1d25@getmailbird.com>
* Anastasios <antonbachin@yahoo.com> [2019-09-25 09:32:35 -0500]:
> Hello,
>
> Consider this program, strtod.c:
>
> #include <stdlib.h>
> #include <stdio.h>
>
> int main()
> {
> printf("%lf\n", strtod("283686952306183", NULL));
> }
>
> With current musl master from Git:
>
> $ musl-gcc -static strtod.c -o a.musl
> $ ./a.musl
> 283686952306176.000000
>
> By comparison, with glibc:
>
> $ gcc -static strtod.c -o a.glibc
> $ ./a.glibc
> 283686952306183.000000
>
works for me on both i486-linux-musl and aarch64-linux-musl.
i have no idea what can cause such bug.
can you try printf with %a and strtod(...)==0x1.020304050607p+48
to see if it's printf %lf that goes wrong?
> The correct binary representation of this float is
>
> 0x42f0203040506070
>
> but musl strtod produces
>
> 0x42f0203040506000
>
> i.e., it fails to set the LSB. I examined this while ruling out printf as the cause.
next prev parent reply other threads:[~2019-09-25 15:06 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-25 14:32 Anastasios
2019-09-25 15:06 ` Szabolcs Nagy [this message]
2019-09-25 15:51 ` Rich Felker
2019-09-25 17:56 ` Anastasios
2019-09-25 18:11 ` Anastasios
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