From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: "Pascal J. Bourguignon" Newsgroups: gmane.emacs.help Subject: Re: How to communicate with a running external process with given PID? Date: Sat, 20 Jul 2013 12:52:56 +0200 Organization: Informatimago Message-ID: <87mwph7bav.fsf@informatimago.com> References: NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: ger.gmane.org 1374317749 14084 80.91.229.3 (20 Jul 2013 10:55:49 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Sat, 20 Jul 2013 10:55:49 +0000 (UTC) To: help-gnu-emacs@gnu.org Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Sat Jul 20 12:55:52 2013 Return-path: Envelope-to: geh-help-gnu-emacs@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 1V0UpI-0006ky-Ly for geh-help-gnu-emacs@m.gmane.org; Sat, 20 Jul 2013 12:55:48 +0200 Original-Received: from localhost ([::1]:46913 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1V0UpI-0007R4-Cx for geh-help-gnu-emacs@m.gmane.org; Sat, 20 Jul 2013 06:55:48 -0400 Original-Path: usenet.stanford.edu!fu-berlin.de!uni-berlin.de!individual.net!not-for-mail Original-Newsgroups: gnu.emacs.help Original-Lines: 53 Original-X-Trace: individual.net XFi2ATmz+USgv8H6GeEDuAGs2uk6/BsWjbLEzI+WQ+XNGOBffi Cancel-Lock: sha1:YmFiYzc1ODkwMWIzNzRkNTA0ODA5NGEwMTU3NDAxNDkxMTY1Yzc3OA== sha1:Q4ajXmOtfHyl1KLPFU28VSShtGM= Face: iVBORw0KGgoAAAANSUhEUgAAADAAAAAwAQMAAABtzGvEAAAABlBMVEUAAAD///+l2Z/dAAAA oElEQVR4nK3OsRHCMAwF0O8YQufUNIQRGIAja9CxSA55AxZgFO4coMgYrEDDQZWPIlNAjwq9 033pbOBPtbXuB6PKNBn5gZkhGa86Z4x2wE67O+06WxGD/HCOGR0deY3f9Ijwwt7rNGNf6Oac l/GuZTF1wFGKiYYHKSFAkjIo1b6sCYS1sVmFhhhahKQssRjRT90ITWUk6vvK3RsPGs+M1RuR mV+hO/VvFAAAAABJRU5ErkJggg== X-Accept-Language: fr, es, en User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.2 (gnu/linux) Original-Xref: usenet.stanford.edu gnu.emacs.help:200003 X-BeenThere: help-gnu-emacs@gnu.org X-Mailman-Version: 2.1.14 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.org@gnu.org Original-Sender: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.help:92269 Archived-At: Thorsten Jolitz writes: > Hi List, > > say I want to call another program (more exactly, another Lisp program > that is not Emacs Lisp) from an Emacs Lisp program. > > My special requirement is that I don't want to start a new Emacs > subprocess, but want to communicate with an existing (running) process. > And there maybe several running instances of this program at the same > time, so I want to communicate with one existing (running) process with > a given PID. > > Now there is splendid support in Emacs for communicating with other > programs, but always based on the assumption that Emacs starts and > controls a new subprocess. > > There is chapter 37.12 "Accessing Other Processes" in the Elisp manual, > and I can do successfully > > ,------------------------- > | (process-attributes PID) > `------------------------- > > to receive a lot of information about the process I want to communicate > with. > > But what then? Where are the (e.g.) `process-send-string' or > `process-send-region' functions for external processes I could use to > communicate with my external program? > > I could run a server in the external lisp program and use a > network-connection-object to send http-requests (e.g. with the help of > emacs-request.el) via TCP - but that seems to be total overkill for my > requirements. > > I just want to use a running external process with a given PID in a > similar way I would use (a)synchronous processes created from Emacs with > `call-process' or `start-process'. How can I do that? > > Maybe there is an obvious answer to this question that I don't see. > Would be nice. Ok, I'll bit the bullet: the only communication channel available to you, a-priori, knowing only the process ID, is the kill(2) syscall. And you're lucky, you can send more than one bit of information with each kill call! -- __Pascal Bourguignon__ http://www.informatimago.com/ A bad day in () is better than a good day in {}. You know you've been lisping too long when you see a recent picture of George Lucas and think "Wait, I thought John McCarthy was dead!" -- Dalek_Baldwin