From mboxrd@z Thu Jan 1 00:00:00 1970 Path: main.gmane.org!not-for-mail From: "Eli Zaretskii" Newsgroups: gmane.emacs.devel Subject: Re: (elisp)Numbers Date: Wed, 22 Oct 2003 17:51:10 +0200 Sender: emacs-devel-bounces+emacs-devel=quimby.gnus.org@gnu.org Message-ID: <1438-Wed22Oct2003175109+0200-eliz@elta.co.il> References: <200310210229.h9L2TGl12085@raven.dms.auburn.edu> <2719-Tue21Oct2003073855+0200-eliz@elta.co.il> Reply-To: Eli Zaretskii NNTP-Posting-Host: deer.gmane.org X-Trace: sea.gmane.org 1066838534 13618 80.91.224.253 (22 Oct 2003 16:02:14 GMT) X-Complaints-To: usenet@sea.gmane.org NNTP-Posting-Date: Wed, 22 Oct 2003 16:02:14 +0000 (UTC) Cc: teirllm@dms.auburn.edu, emacs-devel@gnu.org Original-X-From: emacs-devel-bounces+emacs-devel=quimby.gnus.org@gnu.org Wed Oct 22 18:02:12 2003 Return-path: Original-Received: from quimby.gnus.org ([80.91.224.244]) by deer.gmane.org with esmtp (Exim 3.35 #1 (Debian)) id 1ACLR6-0002qB-00 for ; Wed, 22 Oct 2003 18:02:12 +0200 Original-Received: from monty-python.gnu.org ([199.232.76.173]) by quimby.gnus.org with esmtp (Exim 3.35 #1 (Debian)) id 1ACLR5-0006jT-00 for ; Wed, 22 Oct 2003 18:02:12 +0200 Original-Received: from localhost ([127.0.0.1] helo=monty-python.gnu.org) by monty-python.gnu.org with esmtp (Exim 4.24) id 1ACLQg-0006Oq-4N for emacs-devel@quimby.gnus.org; Wed, 22 Oct 2003 12:01:46 -0400 Original-Received: from list by monty-python.gnu.org with tmda-scanned (Exim 4.24) id 1ACLOB-0003mO-M8 for emacs-devel@gnu.org; Wed, 22 Oct 2003 11:59:11 -0400 Original-Received: from mail by monty-python.gnu.org with spam-scanned (Exim 4.24) id 1ACLNa-0003FQ-S4 for emacs-devel@gnu.org; Wed, 22 Oct 2003 11:59:07 -0400 Original-Received: from [192.114.186.24] (helo=legolas.inter.net.il) by monty-python.gnu.org with esmtp (Exim 4.24) id 1ACLNV-0003DE-IX; Wed, 22 Oct 2003 11:58:29 -0400 Original-Received: from zaretski (pns03-200-33.inter.net.il [80.230.200.33]) by legolas.inter.net.il (Mirapoint Messaging Server MOS 3.3.7-GR) with ESMTP id AOM60132; Wed, 22 Oct 2003 17:56:00 +0200 (IST) Original-To: rms@gnu.org X-Mailer: emacs 21.3.50 (via feedmail 8 I) and Blat ver 1.8.9 In-reply-to: (message from Richard Stallman on Wed, 22 Oct 2003 05:26:02 -0400) X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.2 Precedence: list List-Id: Emacs development discussions. List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+emacs-devel=quimby.gnus.org@gnu.org Xref: main.gmane.org gmane.emacs.devel:17345 X-Report-Spam: http://spam.gmane.org/gmane.emacs.devel:17345 > From: Richard Stallman > Date: Wed, 22 Oct 2003 05:26:02 -0400 > > I have never seen the C9X spec. What are these changes > that are relevant to this? ANSI C89 specifically mandated that math library functions should set errno when they see abnormal arguments; that means implicitly that the library cannot generate a SIGFPE, because SIGFPE will (by default) terminate the program, and thus the program will not have any chance looking at errno. In practice, this required that most environments mask the numerical exceptions, to avoid a SIGFPE. C9x, AFAIU, requires that a numerical exception be raised, as well as that errno be set. So it, in effect, requires a machinery to raise a ``quiet exception'', one that doesn't trigger SIGFPE, at least not by default. In other words, the new ANSI standard codifies the numerical exceptions, which means that library implementors will need to modify the behavior of library functions to comply. That is why I expect some changes in this area as the new standard catches.