From owner-freebsd-standards Wed Oct 16 9:33:39 2002 Delivered-To: freebsd-standards@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 10B3137B401; Wed, 16 Oct 2002 09:33:39 -0700 (PDT) Received: from pintail.mail.pas.earthlink.net (pintail.mail.pas.earthlink.net [207.217.120.122]) by mx1.FreeBSD.org (Postfix) with ESMTP id AE8D943E7B; Wed, 16 Oct 2002 09:33:38 -0700 (PDT) (envelope-from tlambert2@mindspring.com) Received: from pool0308.cvx40-bradley.dialup.earthlink.net ([216.244.43.53] helo=mindspring.com) by pintail.mail.pas.earthlink.net with esmtp (Exim 3.33 #1) id 181r6s-0001Vw-00; Wed, 16 Oct 2002 09:33:26 -0700 Message-ID: <3DAD948D.7705B38F@mindspring.com> Date: Wed, 16 Oct 2002 09:32:13 -0700 From: Terry Lambert X-Mailer: Mozilla 4.79 [en] (Win98; U) X-Accept-Language: en MIME-Version: 1.0 To: Tony Finch Cc: Bruce Evans , Craig Rodrigues , freebsd-standards@FreeBSD.ORG, freebsd-hackers@FreeBSD.ORG Subject: Re: Problem detecting POSIX symbolic constants References: <20021012171803.F15910-100000@gamplex.bde.org> <3DA7E0F4.5988CA77@mindspring.com> <20021012151336.A24868@chiark.greenend.org.uk> <3DA883F2.33E84C@mindspring.com> <20021016121455.A3711@chiark.greenend.org.uk> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-freebsd-standards@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG Tony Finch wrote: > > > No -- the short-circuiting behaviour of && and || only matters if > > > you can have side-effects, which you can't in the preprocessor, > > > so there is no need to implement it (unifdef doesn't). > > > > Consider: > > > > #if _DEFINED_SUPPORTED && defined(SOMETHING) > > That's a syntax error in pre-ANSI preprocessors (unless defined() is > #defined), which won't be bypassed by evaluation shortcutting since > evaluation happens after parsing. No, it's implementation defined. -- Terry To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-standards" in the body of the message