From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Giorgos Keramidas Newsgroups: gmane.emacs.devel Subject: Re: proced: ppid of process ID 0 can be 0 Date: Wed, 24 Dec 2008 00:34:52 +0200 Message-ID: <87wsdqjzar.fsf@kobe.laptop> References: <18765.19040.568030.246241@tfkp04.physik.uni-erlangen.de> <18765.29820.997276.703222@tfkp04.physik.uni-erlangen.de> <18765.51840.943986.608296@tfkp04.physik.uni-erlangen.de> NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: ger.gmane.org 1230071745 14300 80.91.229.12 (23 Dec 2008 22:35:45 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Tue, 23 Dec 2008 22:35:45 +0000 (UTC) Cc: lekktu@gmail.com, Eli Zaretskii , Roland.Winkler@physik.uni-erlangen.de, emacs-devel@gnu.org To: Stefan Monnier Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Tue Dec 23 23:36:50 2008 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([199.232.76.165]) by lo.gmane.org with esmtp (Exim 4.50) id 1LFFrq-0006YK-3f for ged-emacs-devel@m.gmane.org; Tue, 23 Dec 2008 23:36:47 +0100 Original-Received: from localhost ([127.0.0.1]:58142 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1LFFqd-00055B-5M for ged-emacs-devel@m.gmane.org; Tue, 23 Dec 2008 17:35:31 -0500 Original-Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1LFFqX-00054R-I6 for emacs-devel@gnu.org; Tue, 23 Dec 2008 17:35:25 -0500 Original-Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1LFFqW-000540-J5 for emacs-devel@gnu.org; Tue, 23 Dec 2008 17:35:25 -0500 Original-Received: from [199.232.76.173] (port=33611 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1LFFqW-00053v-Fi for emacs-devel@gnu.org; Tue, 23 Dec 2008 17:35:24 -0500 Original-Received: from igloo.linux.gr ([62.1.205.36]:57197) by monty-python.gnu.org with esmtps (TLS-1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1LFFqS-0004ko-Ds; Tue, 23 Dec 2008 17:35:21 -0500 Original-Received: from kobe.laptop (adsl28-172.kln.forthnet.gr [77.49.155.172]) (authenticated bits=128) by igloo.linux.gr (8.14.3/8.14.3/Debian-5) with ESMTP id mBNMYvIM024229 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NOT); Wed, 24 Dec 2008 00:35:03 +0200 Original-Received: from kobe.laptop (kobe.laptop [127.0.0.1]) by kobe.laptop (8.14.3/8.14.3) with ESMTP id mBNMYvIG017201; Wed, 24 Dec 2008 00:34:57 +0200 (EET) (envelope-from keramida@ceid.upatras.gr) Original-Received: (from keramida@localhost) by kobe.laptop (8.14.3/8.14.3/Submit) id mBNMYriW017200; Wed, 24 Dec 2008 00:34:53 +0200 (EET) (envelope-from keramida@ceid.upatras.gr) In-Reply-To: (Stefan Monnier's message of "Tue, 23 Dec 2008 15:41:56 -0500") User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.0.60 (berkeley-unix) X-MailScanner-ID: mBNMYvIM024229 X-Hellug-MailScanner: Found to be clean X-Hellug-MailScanner-SpamCheck: not spam, SpamAssassin (not cached, score=-3.866, required 5, autolearn=not spam, ALL_TRUSTED -1.80, AWL 0.53, BAYES_00 -2.60) X-Hellug-MailScanner-From: keramida@ceid.upatras.gr X-detected-operating-system: by monty-python.gnu.org: GNU/Linux 2.6 (newer, 2) X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Original-Sender: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.devel:107255 Archived-At: On Tue, 23 Dec 2008 15:41:56 -0500, Stefan Monnier wrote: >>> >> Indeed, it should be in system-process-attributes which is already >>> >> OS-dependent. >>> > If you mean by having no ppid attribute, then that's ambiguous, since >>> > an attribute can be missing because it is inaccessible for some >>> > reason, like some kind of failure unrelated to the fact that the >>> > process is really a root of a tree. >>> >>> Seems very hypothetical. >> >> It's not hypothetical, I've seen such cases and reported them to >> Roland. > > What were those cases? > >>> More to the point: even if we could distinguish the "no ppid" from >>> "unkown ppid", it's unclear how Elisp code could make use of it. >> Lisp code cannot, but a primitive written in C can. > > Like what can it do? It can differentiate between FreeBSD 4.3 and FreeBSD 7.2 if they use a different style of `process root', or between Linux 1.2.X, 2.4.X and 2.6.X. Right now, Emacs sets `system-type' to "berkeley-unix" on more than one BSD system. They might be easier to detect at C level.