From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Qiang Guo Newsgroups: gmane.emacs.devel Subject: Quesition about Lisp_Vector Date: Thu, 10 Nov 2011 23:29:16 -0700 Message-ID: NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: dough.gmane.org 1320999923 10183 80.91.229.12 (11 Nov 2011 08:25:23 GMT) X-Complaints-To: usenet@dough.gmane.org NNTP-Posting-Date: Fri, 11 Nov 2011 08:25:23 +0000 (UTC) To: emacs-devel@gnu.org Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Fri Nov 11 09:25:20 2011 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([140.186.70.17]) by lo.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1ROmQK-0008SL-05 for ged-emacs-devel@m.gmane.org; Fri, 11 Nov 2011 09:25:20 +0100 Original-Received: from localhost ([::1]:53963 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ROmQJ-0003yY-Fp for ged-emacs-devel@m.gmane.org; Fri, 11 Nov 2011 03:25:19 -0500 Original-Received: from eggs.gnu.org ([140.186.70.92]:39255) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ROmQG-0003yQ-U2 for emacs-devel@gnu.org; Fri, 11 Nov 2011 03:25:17 -0500 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ROmQF-0007AL-Sr for emacs-devel@gnu.org; Fri, 11 Nov 2011 03:25:16 -0500 Original-Received: from lo.gmane.org ([80.91.229.12]:60885) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ROmQF-00079u-No for emacs-devel@gnu.org; Fri, 11 Nov 2011 03:25:15 -0500 Original-Received: from list by lo.gmane.org with local (Exim 4.69) (envelope-from ) id 1ROmQB-0008Os-38 for emacs-devel@gnu.org; Fri, 11 Nov 2011 09:25:11 +0100 Original-Received: from d173-181-69-148.abhsia.telus.net ([173.181.69.148]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Fri, 11 Nov 2011 09:25:11 +0100 Original-Received: from qguo by d173-181-69-148.abhsia.telus.net with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Fri, 11 Nov 2011 09:25:11 +0100 X-Injected-Via-Gmane: http://gmane.org/ Original-Lines: 20 Original-X-Complaints-To: usenet@dough.gmane.org X-Gmane-NNTP-Posting-Host: d173-181-69-148.abhsia.telus.net User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.0.90 (darwin) Cancel-Lock: sha1:7gE2aABOSOoJDAPf3rAgqnN6LEE= X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6 (newer, 3) X-Received-From: 80.91.229.12 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.14 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-bounces+ged-emacs-devel=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.devel:145980 Archived-At: Hi, I'm new to devel aspect of Emacs. And I'm having a problem reading Emacs source code: in the definition of Lisp_Vector struct Lisp_Vector { EMACS_UINT size; struct Lisp_Vector *next; Lisp_Object contents[1]; }; why contents's size is fixed ? And later when actually allocating space nbytes = sizeof *p + (len - 1) * sizeof p->contents[0]; I don't understand how this nbytes is calculated. why only (len-1) contents[0] ? and how can the size of an array be changed ? Thanks Qiang