From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Emanuel Berg via Users list for the GNU Emacs text editor Newsgroups: gmane.emacs.help Subject: Re: Ctrl-G in emacs does not send SIGINT to the parent shell. How did you do that? Date: Sun, 27 Jun 2021 14:52:25 +0200 Message-ID: <871r8nfp12.fsf@zoho.eu> References: Reply-To: Emanuel Berg Mime-Version: 1.0 Content-Type: text/plain Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="14134"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.0.50 (gnu/linux) To: help-gnu-emacs@gnu.org Cancel-Lock: sha1:7WCk2GiDqjs5q4PzGrSGHDhhTwY= Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Sun Jun 27 14:53:04 2021 Return-path: Envelope-to: geh-help-gnu-emacs@m.gmane-mx.org Original-Received: from lists.gnu.org ([209.51.188.17]) by ciao.gmane.io with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1lxUHY-0003UG-Hs for geh-help-gnu-emacs@m.gmane-mx.org; Sun, 27 Jun 2021 14:53:04 +0200 Original-Received: from localhost ([::1]:55580 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lxUHW-0000Df-HL for geh-help-gnu-emacs@m.gmane-mx.org; Sun, 27 Jun 2021 08:53:02 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:38080) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lxUH6-0000DV-B9 for help-gnu-emacs@gnu.org; Sun, 27 Jun 2021 08:52:36 -0400 Original-Received: from ciao.gmane.io ([116.202.254.214]:57846) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lxUH4-0006hW-Pr for help-gnu-emacs@gnu.org; Sun, 27 Jun 2021 08:52:36 -0400 Original-Received: from list by ciao.gmane.io with local (Exim 4.92) (envelope-from ) id 1lxUH2-0002sc-6C for help-gnu-emacs@gnu.org; Sun, 27 Jun 2021 14:52:32 +0200 X-Injected-Via-Gmane: http://gmane.org/ Mail-Followup-To: help-gnu-emacs@gnu.org Mail-Copies-To: never Received-SPF: pass client-ip=116.202.254.214; envelope-from=geh-help-gnu-emacs@m.gmane-mx.org; helo=ciao.gmane.io X-Spam_score_int: -16 X-Spam_score: -1.7 X-Spam_bar: - X-Spam_report: (-1.7 / 5.0 requ) BAYES_00=-1.9, HEADER_FROM_DIFFERENT_DOMAINS=0.248, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: help-gnu-emacs@gnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Users list for the GNU Emacs text editor List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Original-Sender: "help-gnu-emacs" Xref: news.gmane.io gmane.emacs.help:131301 Archived-At: Masahiro Yamada wrote: > Hello. > > I found this thread reported in 2012: > https://lists.gnu.org/archive/html/bug-gnu-emacs/2012-07/msg00311.html > > It reported that Ctrl-G in an emacs running in a terminal > sends a SIGINT to the parent shell. > > I tested it in newer Emacs version (Emacs 26.3), and found > the behavior was opposite. > > So, something has changed since then. > > I'd like to know what was changed. > > The following is the detailed steps for my tests. > > I invoked 'emacs -nw' from bash running in a terminal. > > Let's say I am using the terminal, /dev/pts/28. > > I used 'stty' from another terminal in order to confirm > 'intr' key was changed to ^G from ^C. > > $ stty -a -F /dev/pts/28 > speed 38400 baud; rows 27; columns 224; line = 0; intr = ^G; > quit = ^G; erase = ^?; kill = ^U; eof = ^D; eol = ; [ > snip ] > > I used strace to check if SIGINT was delivered when > I pressed Ctrl-G. > > I opened another terminal, and ran: > > $ sudo strace -e trace=signal -p > > I opened yet anther terminal, and ran: > > $ sudo strace -e trace=signal -p > > When I pressed Ctrl-G in the Emacs window, I saw SIGINT logs > in the first terminal, which is tracing the emacs. > > In contrast, I saw nothing in the second one, which is > tracing the parent shell. > > In my understanding, when a user provides > keyboard-interrupt, all the foreground processes in that > terminal will receive SIGINT. How can Emacs block SIGINT > from being delivered to the parent shell? > > BTW, I noticed this when I was reading this article: > https://www.cons.org/cracauer/sigint.html > > That article says: > "If C-g is used in Emacs, both the shell and Emacs will > have received SIGINT. Emacs will not exit, the user used > C-g as a normal editing keystroke, he/she does not want > the script to be aborted on C-g." > > It also contradicts to the current behavior of Emacs. > > I am curious how the current behavior was archieved. > > Thanks. :O I like this one :) -- underground experts united https://dataswamp.org/~incal