From mboxrd@z Thu Jan 1 00:00:00 1970 Path: main.gmane.org!not-for-mail From: Han-Wen Nienhuys Newsgroups: gmane.lisp.guile.devel Subject: Re: SCM_PTR_LE ? Date: Thu, 1 Aug 2002 19:16:53 +0200 Sender: guile-devel-admin@gnu.org Message-ID: <15689.27909.668671.145902@meddo.cs.uu.nl> References: <15682.60268.422843.138038@blauw.xs4all.nl> <15687.4663.59228.939494@blauw.xs4all.nl> NNTP-Posting-Host: localhost.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Trace: main.gmane.org 1028222192 18447 127.0.0.1 (1 Aug 2002 17:16:32 GMT) X-Complaints-To: usenet@main.gmane.org NNTP-Posting-Date: Thu, 1 Aug 2002 17:16:32 +0000 (UTC) Cc: guile-devel@gnu.org Return-path: Original-Received: from fencepost.gnu.org ([199.232.76.164]) by main.gmane.org with esmtp (Exim 3.33 #1 (Debian)) id 17aJYs-0004nO-00 for ; Thu, 01 Aug 2002 19:16:31 +0200 Original-Received: from localhost ([127.0.0.1] helo=fencepost.gnu.org) by fencepost.gnu.org with esmtp (Exim 3.35 #1 (Debian)) id 17aJZP-0004Vi-00; Thu, 01 Aug 2002 13:17:03 -0400 Original-Received: from aurora.cs.uu.nl ([131.211.80.20] helo=mail.cs.uu.nl) by fencepost.gnu.org with esmtp (Exim 3.35 #1 (Debian)) id 17aJZG-0004Uw-00 for ; Thu, 01 Aug 2002 13:16:54 -0400 Original-Received: from meddo.cs.uu.nl.cs.uu.nl (meddo.cs.uu.nl [131.211.80.91]) by mail.cs.uu.nl (Postfix) with ESMTP id B7E6D1CB24D; Thu, 1 Aug 2002 19:16:53 +0200 (CEST) Original-To: Marius Vollmer In-Reply-To: X-Mailer: VM 7.03 under Emacs 21.2.1 Errors-To: guile-devel-admin@gnu.org X-BeenThere: guile-devel@gnu.org X-Mailman-Version: 2.0.11 Precedence: bulk List-Help: List-Post: List-Subscribe: , List-Id: Developers list for Guile, the GNU extensibility library List-Unsubscribe: , List-Archive: Xref: main.gmane.org gmane.lisp.guile.devel:919 X-Report-Spam: http://spam.gmane.org/gmane.lisp.guile.devel:919 marius.vollmer@uni-dortmund.de writes: > > I think that pointer comparison is pretty well defined in ANSI C; can > > you think of a solid reason to support them? > > What is that definition? I think ANSI C only defines the outcome of > comparisons for pointers that point into the same object, i.e., the I stand corrected, I looked it up in the N843 document (http://www.dkuug.dk/JTC1/SC22/WG14/www/docs/n843.htm), and you're right. > same array or a single block returned from malloc. A consequence > would be that you can not reliably test whether a pointer does point > into some object, since the results are not defined when it points > outside. For example, is the following guaranteed to print "sane"? However, that point is completely moot, since the binary search code in heap_segment () (new GC: scm_find_heap_segment_containing_object) is full of code that compares pointers outside their blocks. Unless that is scrapped (not), SCM_PTR_* can go. -- Han-Wen Nienhuys | hanwen@cs.uu.nl | http://www.cs.uu.nl/~hanwen/ _______________________________________________ Guile-devel mailing list Guile-devel@gnu.org http://mail.gnu.org/mailman/listinfo/guile-devel