From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: "Stephen J. Turnbull" Newsgroups: gmane.emacs.devel Subject: The emacs_backtrace "feature" Date: Sat, 22 Sep 2012 01:49:50 +0900 Message-ID: <87vcf7nwwh.fsf@uwakimon.sk.tsukuba.ac.jp> References: <83lig3yaci.fsf@gnu.org> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 X-Trace: ger.gmane.org 1348246207 30238 80.91.229.3 (21 Sep 2012 16:50:07 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Fri, 21 Sep 2012 16:50:07 +0000 (UTC) Cc: emacs-devel@gnu.org To: Eli Zaretskii Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Fri Sep 21 18:50:11 2012 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1TF6Qc-0005Ka-U3 for ged-emacs-devel@m.gmane.org; Fri, 21 Sep 2012 18:50:11 +0200 Original-Received: from localhost ([::1]:48792 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TF6QY-0002mB-2N for ged-emacs-devel@m.gmane.org; Fri, 21 Sep 2012 12:50:06 -0400 Original-Received: from eggs.gnu.org ([208.118.235.92]:53136) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TF6QR-0002kS-4o for emacs-devel@gnu.org; Fri, 21 Sep 2012 12:50:04 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TF6QL-00026z-CZ for emacs-devel@gnu.org; Fri, 21 Sep 2012 12:49:59 -0400 Original-Received: from mgmt2.sk.tsukuba.ac.jp ([130.158.97.224]:55062) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TF6QJ-00026g-NR; Fri, 21 Sep 2012 12:49:51 -0400 Original-Received: from uwakimon.sk.tsukuba.ac.jp (uwakimon.sk.tsukuba.ac.jp [130.158.99.156]) by mgmt2.sk.tsukuba.ac.jp (Postfix) with ESMTP id D18C49707DC; Sat, 22 Sep 2012 01:49:50 +0900 (JST) Original-Received: by uwakimon.sk.tsukuba.ac.jp (Postfix, from userid 1000) id 97D1A1A32EF; Sat, 22 Sep 2012 01:49:50 +0900 (JST) In-Reply-To: <83lig3yaci.fsf@gnu.org> X-Mailer: VM 8.0.12-devo-585 under 21.5 (beta32) "habanero" b0d40183ac79 XEmacs Lucid (x86_64-unknown-linux) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6 (newer, 3) X-Received-From: 130.158.97.224 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Original-Sender: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.devel:153439 Archived-At: Eli Zaretskii writes: > If you didn't make a point of setting up [for a crash], you'll > lose precious information. [...] > Why not use the good old core dump files? They have all the > information that is needed for debugging the crash, Assuming that they exist. Sadly, on modern GNU systems (as distributed by the major distros) they usually don't ... unless the user makes a point of setting up for a crash. As you say, people usually don't. > But here we do that voluntarily and by default. Why? Because modern GNU systems (as distributed by the major distros) usually *do* come with installable "debug" packages that contain the symbol table that gets stripped out by default. I agree, trying to find the Corresponding Source for "find_file_internal + 0xDEAD" is pretty darn annoying, but I've debugged a lot of issues with just the most recently called function name. What bugs me a lot more is inability to get at variable values, especially actual parameters. But thanks to the wonders of modern GCC, the value of whatever you're interested in is , so you also get that feature for free with modern GNU systems as distributed by the major distros. (I hear that really recent GDB does a much better job of disentangling most optimizations, but guess what isn't installed on ....) > Otherwise, I guess we will find soon enough whether this is a great > feature or not. I agree that core dumps are better (but habitually running under gdb is even better yet :-). But it's nice to get at least some information out of random users who for some strange reason don't expect Emacs to crash. :-)