From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 8695 invoked by alias); 2 Nov 2007 11:36:18 -0000 Received: (qmail 8686 invoked by uid 22791); 2 Nov 2007 11:36:18 -0000 X-Spam-Check-By: sourceware.org Received: from NaN.false.org (HELO nan.false.org) (208.75.86.248) by sourceware.org (qpsmtpd/0.31) with ESMTP; Fri, 02 Nov 2007 11:36:15 +0000 Received: from nan.false.org (localhost [127.0.0.1]) by nan.false.org (Postfix) with ESMTP id 013069829E; Fri, 2 Nov 2007 11:36:13 +0000 (GMT) Received: from caradoc.them.org (22.svnf5.xdsl.nauticom.net [209.195.183.55]) by nan.false.org (Postfix) with ESMTP id 180C898103; Fri, 2 Nov 2007 11:36:11 +0000 (GMT) Received: from drow by caradoc.them.org with local (Exim 4.68) (envelope-from ) id 1Inuos-0004ST-Qu; Fri, 02 Nov 2007 07:36:10 -0400 Date: Fri, 02 Nov 2007 11:36:00 -0000 From: Daniel Jacobowitz To: Nick Roberts Cc: Vladimir Prus , gdb-patches@sources.redhat.com Subject: Re: [PATCH] MI: lvalues and variable_editable Message-ID: <20071102113610.GA16883@caradoc.them.org> Mail-Followup-To: Nick Roberts , Vladimir Prus , gdb-patches@sources.redhat.com References: <18210.27153.559569.601092@kahikatea.snap.net.nz> <200710311458.58112.ghost@cs.msu.su> <18217.23406.21406.920384@kahikatea.snap.net.nz> <200710312247.40840.ghost@cs.msu.su> <20071101153955.GA20676@caradoc.them.org> <18218.42464.899738.594153@kahikatea.snap.net.nz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <18218.42464.899738.594153@kahikatea.snap.net.nz> User-Agent: Mutt/1.5.15 (2007-04-09) X-IsSubscribed: yes Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org X-SW-Source: 2007-11/txt/msg00019.txt.bz2 On Fri, Nov 02, 2007 at 05:21:52PM +1300, Nick Roberts wrote: > In that case for such a varobj, var->value == NULL must indicate that the > memory was inaccessible at the _last_ update, or creation, and it may no longer > be inaccessible. Describing it as "noneditable" may then be a bit misleading. The next time it's -var-update'd it may get a new value; presumably the IDE does that periodically. > I'm surprised that there is "no way to be sure without trying to write". I > know that 0x0 is inaccessible memory, and presumably the OS has a better idea > about what is and isn't accessible. It won't tell us, though. Most systems have no interface to ask this question. Unix ptrace doesn't, hardware JTAG doesn't... whether you can always write to RAM from a hardware JTAG device depends on whether you're going through the MMU (memory management unit) or not for writes. -- Daniel Jacobowitz CodeSourcery