From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 13247 invoked by alias); 6 Oct 2011 08:16:33 -0000 Received: (qmail 13236 invoked by uid 22791); 6 Oct 2011 08:16:29 -0000 X-SWARE-Spam-Status: No, hits=-2.8 required=5.0 tests=ALL_TRUSTED,AWL,BAYES_00 X-Spam-Check-By: sourceware.org Received: from localhost (HELO sourceware.org) (127.0.0.1) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Thu, 06 Oct 2011 08:16:14 +0000 From: "jakub at redhat dot com" To: glibc-bugs@sources.redhat.com Subject: [Bug libc/13246] RFE: strtold: do not include uninitialized bytes when converting "NaN" Date: Thu, 06 Oct 2011 08:16:00 -0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: glibc X-Bugzilla-Component: libc X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: jakub at redhat dot com X-Bugzilla-Status: RESOLVED X-Bugzilla-Priority: P2 X-Bugzilla-Assigned-To: drepper.fsp at gmail dot com X-Bugzilla-Target-Milestone: --- X-Bugzilla-Changed-Fields: CC Message-ID: In-Reply-To: References: X-Bugzilla-URL: http://sourceware.org/bugzilla/ Auto-Submitted: auto-generated Content-Type: text/plain; charset="UTF-8" MIME-Version: 1.0 Mailing-List: contact glibc-bugs-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Post: List-Help: , Sender: glibc-bugs-owner@sourceware.org X-SW-Source: 2011-10/txt/msg00014.txt.bz2 http://sourceware.org/bugzilla/show_bug.cgi?id=13246 Jakub Jelinek changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |jakub at redhat dot com --- Comment #4 from Jakub Jelinek 2011-10-06 08:15:00 UTC --- I think it is neither. On x86_64/i686, the hw long double is 80 bit, but sizeof (long double) is 16 (on x86_64) resp. 12 (on i686). If you store a long double from a hw register into memory, it only stores there the 80 bits, the remaining bits are left unmodified, it is padding that is ignored, thus e.g. if it is stored onto the stack, whatever bits were in the padding before are kept there. It is a bug to look for something meaningful among the padding bits. That is similar to looking at padding in structures, undefined behavior in C. -- Configure bugmail: http://sourceware.org/bugzilla/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are on the CC list for the bug.