Newsgroups: php.internals Path: news.php.net Xref: news.php.net php.internals:24292 Return-Path: Mailing-List: contact internals-help@lists.php.net; run by ezmlm Delivered-To: mailing list internals@lists.php.net Received: (qmail 18033 invoked by uid 1010); 8 Jul 2006 09:18:01 -0000 Delivered-To: ezmlm-scan-internals@lists.php.net Delivered-To: ezmlm-internals@lists.php.net Received: (qmail 18017 invoked from network); 8 Jul 2006 09:18:01 -0000 Received: from unknown (HELO lists.php.net) (127.0.0.1) by localhost with SMTP; 8 Jul 2006 09:18:01 -0000 Authentication-Results: pb1.pair.com header.from=pierre.php@gmail.com; domainkeys=good DomainKey-Status: good X-DomainKeys: Ecelerity dk_validate implementing draft-delany-domainkeys-base-01 X-PHP-List-Original-Sender: pierre.php@gmail.com X-Host-Fingerprint: 66.249.92.170 ug-out-1314.google.com Linux 2.4/2.6 Received: from ([66.249.92.170:39522] helo=ug-out-1314.google.com) by pb1.pair.com (ecelerity 2.1.1.3 r(11751M)) with ESMTP id E6/11-16663-6487FA44 for ; Sat, 08 Jul 2006 05:17:59 -0400 Received: by ug-out-1314.google.com with SMTP id m2so894153ugc for ; Sat, 08 Jul 2006 02:17:55 -0700 (PDT) DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=E0XYZ3KCdhNfXBxNsiz/CN3skDTjArKGAuuUNEo0dQ3WyRyNEcCP+qC2qipyzJbnM3cK0fPH54LhFND7eQe++B+vky/rvFajqS2CRmkFlWejijQBO60lP5RiQVdBqxI8Y3oaPNQAqADwU1tru22nyWJHUXMLDgE6OMqCucSsQTY= Received: by 10.66.219.11 with SMTP id r11mr2855395ugg; Sat, 08 Jul 2006 02:17:54 -0700 (PDT) Received: by 10.66.222.12 with HTTP; Sat, 8 Jul 2006 02:17:54 -0700 (PDT) Message-ID: Date: Sat, 8 Jul 2006 11:17:54 +0200 To: "Matt W" Cc: internals@lists.php.net In-Reply-To: <002701c6a26e$a1746560$0201a8c0@pc1> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <002701c6a26e$a1746560$0201a8c0@pc1> Subject: Re: [PHP-DEV] Use of "empty character constant?" From: pierre.php@gmail.com (Pierre) On 7/8/06, Matt W wrote: > Hi all, > > I'm a C newbie and just started experimenting with the PHP internals a > couple weeks ago... A few days ago I noticed assignment/comparison of char > variables to '' (nothing between single quotes) in, for example, the > is_numeric_string function (zend_operators.h), snprintf.c, spprintf.c, etc. > I don't understand what it's doing. :-/ The only references I can find are > about "empty character constant" compiler errors, which is what happens if I > try to use '' in the same way (VC++ Express). Though PHP compiles fine with > these "constructs," so something must be special there? http://publications.gbdirect.co.uk/c_book/chapter5/character_handling.html Cheers, --Pierre