From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Richard Stallman Newsgroups: gmane.emacs.devel Subject: Re: Using the GNU GMP Library for Bignums in Emacs Date: Mon, 23 Apr 2018 22:54:20 -0400 Message-ID: References: <29f933ac-a6bf-8742-66a7-0a9d6d3e5a88@disroot.org> <87k1t05wz4.fsf@metalevel.at> <55776605-8940-0a4a-34fb-f3d1b955ab12@cs.ucla.edu> <831sf8x8o6.fsf@gnu.org> Reply-To: rms@gnu.org NNTP-Posting-Host: blaine.gmane.org Content-Type: text/plain; charset=Utf-8 X-Trace: blaine.gmane.org 1524538360 7728 195.159.176.226 (24 Apr 2018 02:52:40 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Tue, 24 Apr 2018 02:52:40 +0000 (UTC) Cc: eliz@gnu.org, triska@metalevel.at, emacs-devel@gnu.org To: Paul Eggert Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Tue Apr 24 04:52:36 2018 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1fAo4G-0001sr-IX for ged-emacs-devel@m.gmane.org; Tue, 24 Apr 2018 04:52:32 +0200 Original-Received: from localhost ([::1]:56258 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fAo6N-00065S-AA for ged-emacs-devel@m.gmane.org; Mon, 23 Apr 2018 22:54:43 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:57541) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fAo67-00064w-Bs for emacs-devel@gnu.org; Mon, 23 Apr 2018 22:54:28 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fAo66-0000LI-Bl for emacs-devel@gnu.org; Mon, 23 Apr 2018 22:54:27 -0400 Original-Received: from fencepost.gnu.org ([2001:4830:134:3::e]:54648) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fAo61-0000HW-Hb; Mon, 23 Apr 2018 22:54:21 -0400 Original-Received: from rms by fencepost.gnu.org with local (Exim 4.82) (envelope-from ) id 1fAo60-0007tN-Tl; Mon, 23 Apr 2018 22:54:20 -0400 In-reply-to: (message from Paul Eggert on Sun, 22 Apr 2018 21:21:02 -0700) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 2001:4830:134:3::e X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.21 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" Xref: news.gmane.org gmane.emacs.devel:224821 Archived-At: [[[ To any NSA and FBI agents reading my email: please consider ]]] [[[ whether defending the US Constitution against all enemies, ]]] [[[ foreign or domestic, requires you to follow Snowden's example. ]]] > Allowing immediate quitting from arbitrary points in execution causes problems Immediate quitting was never allowed from arbitrary points in execution. Only in places where immediate_quit was nonzero. Those were generally code whose side effects would not matter unless they were allowed to finish. > In the old days we could assume that execution order at the > machine level was the same order as in the C program source code, > which meant that as long as the C source code did things in the > right order Emacs could survive immediate quitting. That > assumption is no longer true. That problem exists in theory. Did the problem actually occur? > To do things safely now, we need to either (1) add critical > sections to Emacs where appropriate, or (2) test the quit flag at > appropriate intervals ... in each and every place where immediate_quit was formerly used. In practice (2) is easier to implement and > to maintain. If (2) means to check for quitting as needed in each and every place code where immediate_quit was formerly used, that would thoroughly do the job, but did we handle all of those places? -- Dr Richard Stallman President, Free Software Foundation (https://gnu.org, https://fsf.org) Internet Hall-of-Famer (https://internethalloffame.org) Skype: No way! See https://stallman.org/skype.html.