From mboxrd@z Thu Jan 1 00:00:00 1970 Path: main.gmane.org!not-for-mail From: David Kastrup Newsgroups: gmane.emacs.devel Subject: Re: xasserts and vertical motion. Date: Tue, 01 Mar 2005 15:57:58 +0100 Message-ID: References: NNTP-Posting-Host: main.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: sea.gmane.org 1109690346 7289 80.91.229.2 (1 Mar 2005 15:19:06 GMT) X-Complaints-To: usenet@sea.gmane.org NNTP-Posting-Date: Tue, 1 Mar 2005 15:19:06 +0000 (UTC) Cc: emacs-devel@gnu.org Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Tue Mar 01 16:19:05 2005 Original-Received: from lists.gnu.org ([199.232.76.165]) by ciao.gmane.org with esmtp (Exim 4.43) id 1D698X-00004q-Dx for ged-emacs-devel@m.gmane.org; Tue, 01 Mar 2005 16:18:13 +0100 Original-Received: from localhost ([127.0.0.1] helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1D69R7-00084P-5r for ged-emacs-devel@m.gmane.org; Tue, 01 Mar 2005 10:37:25 -0500 Original-Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1D69Eq-0001xN-CP for emacs-devel@gnu.org; Tue, 01 Mar 2005 10:24:45 -0500 Original-Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1D69Eh-0001uj-Fw for emacs-devel@gnu.org; Tue, 01 Mar 2005 10:24:37 -0500 Original-Received: from [199.232.76.173] (helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1D69Ee-0001lT-V3 for emacs-devel@gnu.org; Tue, 01 Mar 2005 10:24:32 -0500 Original-Received: from [199.232.76.164] (helo=fencepost.gnu.org) by monty-python.gnu.org with esmtp (Exim 4.34) id 1D68p4-0004Le-AO for emacs-devel@gnu.org; Tue, 01 Mar 2005 09:58:06 -0500 Original-Received: from localhost ([127.0.0.1] helo=lola.goethe.zz) by fencepost.gnu.org with esmtp (Exim 4.34) id 1D68ox-0008Jf-O7; Tue, 01 Mar 2005 09:58:00 -0500 Original-To: rms@gnu.org In-Reply-To: (Richard Stallman's message of "Tue, 22 Feb 2005 03:42:55 -0500") User-Agent: Gnus/5.11 (Gnus v5.11) Emacs/22.0.50 (gnu/linux) X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Original-Sender: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org X-MailScanner-To: ged-emacs-devel@m.gmane.org Xref: main.gmane.org gmane.emacs.devel:33981 X-Report-Spam: http://spam.gmane.org/gmane.emacs.devel:33981 Richard Stallman writes: > b) they don't check for _structural_ incoherence (namely that > Emacs' internal data structures are not garbled), but for > _visual_ incoherence. But for debugging this one needs > information about what kind of things happen on the screen at > the time, and just in what manner some expectations might get > violated. This is much easier to get when Emacs remains > operative and gets a chance to _display_ the result of the > operation instead of committing suicide. > > You should be able to continue by typing the GDB `return' command > and then `c'. Does it work? Not really. I think that "abort" may be marked as "noreturn" in the GCC header files, and so GCC does not bother keeping the stack or code in a consistent state after return. As another consequence, without an explicit -fno-crossjumping placed into CFLAGS, all asserts in a function will use the same call to abort(), which means that the traceback from gdb will pick a random (but usually fixed) assertion line in the source code as the prospective culprit. I'll mention that option in the debugging instructions if it is not already there. -- David Kastrup, Kriemhildstr. 15, 44793 Bochum