From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <sourceware-bugzilla@sourceware.org>
Received: by sourceware.org (Postfix, from userid 48)
 id 9D1EA3857403; Thu,  9 Sep 2021 12:21:19 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 9D1EA3857403
From: "arthur200126 at gmail dot com" <sourceware-bugzilla@sourceware.org>
To: glibc-bugs@sourceware.org
Subject: [Bug math/28322] New: Specify parsing of nan?
Date: Thu, 09 Sep 2021 12:21:19 +0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: new
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: glibc
X-Bugzilla-Component: math
X-Bugzilla-Version: 2.35
X-Bugzilla-Keywords: 
X-Bugzilla-Severity: enhancement
X-Bugzilla-Who: arthur200126 at gmail dot com
X-Bugzilla-Status: UNCONFIRMED
X-Bugzilla-Resolution: 
X-Bugzilla-Priority: P2
X-Bugzilla-Assigned-To: unassigned at sourceware dot org
X-Bugzilla-Target-Milestone: ---
X-Bugzilla-Flags: 
X-Bugzilla-Changed-Fields: bug_id short_desc product version bug_status
 bug_severity priority component assigned_to reporter target_milestone
Message-ID: <bug-28322-131@http.sourceware.org/bugzilla/>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
X-Bugzilla-URL: http://sourceware.org/bugzilla/
Auto-Submitted: auto-generated
MIME-Version: 1.0
X-BeenThere: glibc-bugs@sourceware.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Glibc-bugs mailing list <glibc-bugs.sourceware.org>
List-Unsubscribe: <https://sourceware.org/mailman/options/glibc-bugs>,
 <mailto:glibc-bugs-request@sourceware.org?subject=unsubscribe>
List-Archive: <https://sourceware.org/pipermail/glibc-bugs/>
List-Help: <mailto:glibc-bugs-request@sourceware.org?subject=help>
List-Subscribe: <https://sourceware.org/mailman/listinfo/glibc-bugs>,
 <mailto:glibc-bugs-request@sourceware.org?subject=subscribe>
X-List-Received-Date: Thu, 09 Sep 2021 12:21:19 -0000

https://sourceware.org/bugzilla/show_bug.cgi?id=3D28322

            Bug ID: 28322
           Summary: Specify parsing of nan?
           Product: glibc
           Version: 2.35
            Status: UNCONFIRMED
          Severity: enhancement
          Priority: P2
         Component: math
          Assignee: unassigned at sourceware dot org
          Reporter: arthur200126 at gmail dot com
  Target Milestone: ---

The current glibc documentation at [1] states:
  [1]:
https://www.gnu.org/software/libc/manual/html_node/Parsing-of-Floats.html

> The strings "nan" and "nan(chars=E2=80=A6)" are converted to NaN. Again, =
case is
> ignored. If chars=E2=80=A6 are provided, they are used in some unspecifie=
d fashion to
> select a particular representation of NaN (there can be several).

I find this documentation odd as glibc itself appears to have one single me=
thod
for parsing the "chars..." part in nan, defined in the source files
strtod_nan_*.c. Moreover, since commit
e02cabecf0d025ec4f4ddee290bdf7aadb873bb3,[2] the format is locale-independe=
nt,
making it more conducive to documentation.=20

  [2]:
https://sourceware.org/git/?p=3Dglibc.git;a=3Dcommit;h=3De02cabecf0d025ec4f=
4ddee290bdf7aadb873bb3

A proposed wording for the current behavior would be:

> If chars... are provided, they are parsed into a NaN payload as if the
> sequence is given to strtoull() with a base argument of 0. (Something abo=
ut
> discarding stray characters here.)

I should note that there is still ambiguity in "parsed into a payload" with
regard to how. Apparently glibc has a setpayload(), but the SET_NAN_PAYLOAD
macro does not use it.

--=20
You are receiving this mail because:
You are on the CC list for the bug.=