From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Emanuel Berg Newsgroups: gmane.emacs.help Subject: Re: Feature request: Expose system `exec` as a built-in elisp function Date: Wed, 13 Aug 2014 20:45:02 +0200 Organization: Aioe.org NNTP Server Message-ID: <87mwb8tej5.fsf@debian.uxu> References: NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: ger.gmane.org 1407955525 31364 80.91.229.3 (13 Aug 2014 18:45:25 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Wed, 13 Aug 2014 18:45:25 +0000 (UTC) To: help-gnu-emacs@gnu.org Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Wed Aug 13 20:45:19 2014 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 1XHdXz-0001Uc-2e for geh-help-gnu-emacs@m.gmane.org; Wed, 13 Aug 2014 20:45:19 +0200 Original-Received: from localhost ([::1]:49580 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XHdXy-0006mq-N9 for geh-help-gnu-emacs@m.gmane.org; Wed, 13 Aug 2014 14:45:18 -0400 Original-Path: usenet.stanford.edu!news.tele.dk!news.tele.dk!small.news.tele.dk!newsfeed.xs4all.nl!newsfeed1.news.xs4all.nl!xs4all!news.stack.nl!aioe.org!.POSTED!not-for-mail Original-Newsgroups: gnu.emacs.help Original-Lines: 29 Original-NNTP-Posting-Host: SIvZRMPqRkkTHAHL6NkRuw.user.speranza.aioe.org Original-X-Complaints-To: abuse@aioe.org User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.3 (gnu/linux) X-Notice: Filtered by postfilter v. 0.8.2 Cancel-Lock: sha1:JIuPNWLo6w2O5GbJGBEuK5k2V/I= Mail-Copies-To: never Original-Xref: usenet.stanford.edu gnu.emacs.help:206914 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:99190 Archived-At: Andrew Pennebaker writes: > That's what I thought, at first. exec has the > additional semantic that it replaces the current > process with the system call, so it's more efficient > for certain tasks. Yes, exec (man "exec") does this. It accepts an argument for what program to execute, and then a list of arguments (the argv) to be inputed that program. It is usually used with fork. One process devides itself with fork(), which returns twice (magic!), and from the return values the child process can be identified; then, the child uses exec to fill itself with software so it can do something productive. So as for this method and setting (which may be different from yours) it is not a matter of efficiency, it is rather that without exec, often there isn't anything for the child to do. (You probably already know all this.) So if you want to replace the current process, can't you just have the current process execute whatever code you had in mind for exec? -- underground experts united