From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Stefan Monnier Newsgroups: gmane.emacs.devel Subject: Re: Dynamic loading progress Date: Mon, 14 Sep 2015 00:18:20 -0400 Message-ID: References: <85mw20gmeo.fsf@stephe-leake.org> <878u97nyjn.fsf@lifelogs.com> <86d1yirnqw.fsf@stephe-leake.org> <87si7977rs.fsf@tromey.com> <55DB7C3D.4090106@cs.ucla.edu> <55DE75FD.8020308@cs.ucla.edu> <55F5DD8C.70506@dancol.org> <55F62C16.4000105@dancol.org> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: ger.gmane.org 1442204339 4687 80.91.229.3 (14 Sep 2015 04:18:59 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Mon, 14 Sep 2015 04:18:59 +0000 (UTC) Cc: Paul Eggert , Emacs development discussions , Philipp Stephani , =?windows-1252?Q?Aur=E9lien?= Aptel , Tom Tromey , Stephen Leake To: Daniel Colascione Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Mon Sep 14 06:18:43 2015 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 1ZbLE2-0001TL-QP for ged-emacs-devel@m.gmane.org; Mon, 14 Sep 2015 06:18:42 +0200 Original-Received: from localhost ([::1]:38252 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZbLE1-0006BR-L5 for ged-emacs-devel@m.gmane.org; Mon, 14 Sep 2015 00:18:41 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:51681) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZbLDo-0006BF-Vr for emacs-devel@gnu.org; Mon, 14 Sep 2015 00:18:29 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZbLDk-00062O-V8 for emacs-devel@gnu.org; Mon, 14 Sep 2015 00:18:28 -0400 Original-Received: from ironport2-out.teksavvy.com ([206.248.154.181]:1676) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZbLDk-00062J-R2 for emacs-devel@gnu.org; Mon, 14 Sep 2015 00:18:24 -0400 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: A0CdDQA731xV/0jo92hcgxCEAshgBAICgTw9EAEBAQEBAQGBCkEFg10BAQMBViMFCwsOJhIUGA0kiDcIzyMBAQEBBgIBH4s6hQUHhC0FkDSkUCOBZoIuIoJ4AQEB X-IPAS-Result: A0CdDQA731xV/0jo92hcgxCEAshgBAICgTw9EAEBAQEBAQGBCkEFg10BAQMBViMFCwsOJhIUGA0kiDcIzyMBAQEBBgIBH4s6hQUHhC0FkDSkUCOBZoIuIoJ4AQEB X-IronPort-AV: E=Sophos;i="5.13,465,1427774400"; d="scan'208";a="164750865" Original-Received: from 104-247-232-72.cpe.teksavvy.com (HELO ceviche.home) ([104.247.232.72]) by ironport2-out.teksavvy.com with ESMTP/TLS/DHE-RSA-AES256-SHA; 14 Sep 2015 00:18:22 -0400 Original-Received: by ceviche.home (Postfix, from userid 20848) id A26F666107; Mon, 14 Sep 2015 00:18:20 -0400 (EDT) In-Reply-To: <55F62C16.4000105@dancol.org> (Daniel Colascione's message of "Sun, 13 Sep 2015 19:08:22 -0700") User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.0.50 (gnu/linux) X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 206.248.154.181 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:189914 Archived-At: >> AFAICT, the only odd case I can think of is the following: >> >> 1- Emacs calls some module code via the new API. >> 2- This code (which is Emacs-specific) will know about Fthrow. >> 3- It may call some non-Emacs-specific code from some other library. >> 4- This non-Emacs-specific code calls back to some Emacs-specific function. >> 5- This Emacs-specific function calls Fthrow/Fsignal. >> >> Where the problem only shows if/when we reach point 5. >> >> This problem can be handled between 4 and 5 by using an appropriate >> internal_condition_case. >> >> Is there some other situation you're thinking of? > Nobody is going to consider that case. Which other case are you thinking about then? > It'll be hard enough to get developers to properly unwind their own > code, especially because we're only talking about a case that's active > when things go wrong. Of course we can make non-local control flow > work: it works well enough inside Emacs. You lost me. > I'm objecting to this approach because it's a bug machine, especially What is "this approach"? > without the Emacs Lisp and GC machinery. AFAIK we do have the Elisp and the GC machinery available. > It breaks C++ RAII, because there's no way the longjmp out of Emacs > can run C++ destructors. This seems to refer to the "point 5" above. As mentioned it's easy to prevent the longjmp from escaping back into the surrounding non-Emacs (e.g. C++) code. Stefan