From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.devel Subject: Re: question about `display-graphic-p' and emacs daemon Date: Wed, 21 Nov 2012 20:05:54 +0200 Message-ID: <83liduvnjx.fsf@gnu.org> References: <5117FACB1DD14041804B94DDD6B2DDF3@us.oracle.com> Reply-To: Eli Zaretskii NNTP-Posting-Host: plane.gmane.org X-Trace: ger.gmane.org 1353521187 2521 80.91.229.3 (21 Nov 2012 18:06:27 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Wed, 21 Nov 2012 18:06:27 +0000 (UTC) Cc: emacs-devel@gnu.org To: Drew Adams Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Wed Nov 21 19:06:38 2012 Return-path: Envelope-to: ged-emacs-devel@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 1TbEgx-0003Vw-2V for ged-emacs-devel@m.gmane.org; Wed, 21 Nov 2012 19:06:31 +0100 Original-Received: from localhost ([::1]:55631 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TbEgm-0001DV-CF for ged-emacs-devel@m.gmane.org; Wed, 21 Nov 2012 13:06:20 -0500 Original-Received: from eggs.gnu.org ([208.118.235.92]:51561) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TbEgj-0001DJ-6J for emacs-devel@gnu.org; Wed, 21 Nov 2012 13:06:18 -0500 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TbEgf-0006Ib-5N for emacs-devel@gnu.org; Wed, 21 Nov 2012 13:06:17 -0500 Original-Received: from mtaout23.012.net.il ([80.179.55.175]:42776) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TbEge-0006IV-T4 for emacs-devel@gnu.org; Wed, 21 Nov 2012 13:06:13 -0500 Original-Received: from conversion-daemon.a-mtaout23.012.net.il by a-mtaout23.012.net.il (HyperSendmail v2007.08) id <0MDU00L00NK45500@a-mtaout23.012.net.il> for emacs-devel@gnu.org; Wed, 21 Nov 2012 20:06:11 +0200 (IST) Original-Received: from HOME-C4E4A596F7 ([87.69.4.28]) by a-mtaout23.012.net.il (HyperSendmail v2007.08) with ESMTPA id <0MDU00K2BNMAY5A0@a-mtaout23.012.net.il>; Wed, 21 Nov 2012 20:06:11 +0200 (IST) In-reply-to: <5117FACB1DD14041804B94DDD6B2DDF3@us.oracle.com> X-012-Sender: halo1@inter.net.il X-detected-operating-system: by eggs.gnu.org: Solaris 10 X-Received-From: 80.179.55.175 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:155028 Archived-At: > From: "Drew Adams" > Date: Wed, 21 Nov 2012 07:16:16 -0800 > > But shouldn't it be possible for Emacs to determine the display type without > actually displaying a frame? Why do you need that? The display-*-P functions are mainly for testing what the current frame can or cannot do, so that Lisp applications could fall back on alternative methods if the best alternative cannot be supported. E.g., if fringes are not available, a Lisp program could display something in an overlay or in margins. If you want to know whether the current Emacs executable can do something, it is better to use fboundp and featurep instead. > 2. While looking for the answer, I checked the doc for `display-graphic-p'. It > says that argument DISPLAY can be a display name, as an alternative to being a > frame name or nil. But it says nothing about what a "display name" means wrt > Emacs Lisp. > > What form does it take? Is it a Unix/Linux X-Window display name? Yes. A cross reference to "Multiple Terminals" would be good there. > What about on MS Windows? The Windows build does not support multiple displays. > The closest I found to describing DISPLAY is in `Multiple Terminals'. It > describes X-Window displays as having names of the form HOST:SERVER.SCREEN. > What about non X-Window displays? There are none; X-Window displays are the only ones Emacs supports. > If I eval (x-display-list) on MS Windows I see ("w32"), but I don't see that > form of DISPLAY described anywhere. That's a fake name, just so that code that looks at this will have some string to play with. It has no meaning. > And I see that (framep (selected-frame)) returns `w32' (a symbol > this time). Yes, and that one _is_ documented.