From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail1.windriver.com (mail1.windriver.com [147.11.146.13]) by mail.openembedded.org (Postfix) with ESMTP id 648C070734 for ; Tue, 22 Jul 2014 17:04:03 +0000 (UTC) Received: from ALA-HCA.corp.ad.wrs.com (ala-hca.corp.ad.wrs.com [147.11.189.40]) by mail1.windriver.com (8.14.5/8.14.5) with ESMTP id s6MH44OB002405 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=FAIL) for ; Tue, 22 Jul 2014 10:04:05 -0700 (PDT) Received: from msp-dhcp53.wrs.com (172.25.34.53) by ALA-HCA.corp.ad.wrs.com (147.11.189.50) with Microsoft SMTP Server id 14.3.169.1; Tue, 22 Jul 2014 10:04:04 -0700 Message-ID: <53CE9984.3090106@windriver.com> Date: Tue, 22 Jul 2014 12:04:04 -0500 From: Mark Hatle Organization: Wind River Systems User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.9; rv:24.0) Gecko/20100101 Thunderbird/24.6.0 MIME-Version: 1.0 To: References: In-Reply-To: Subject: Re: why conditional assignment of DEPLOY_DIR_IMAGE in bitbake.conf? X-BeenThere: openembedded-core@lists.openembedded.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Patches and discussions about the oe-core layer List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 22 Jul 2014 17:04:06 -0000 Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit On 7/22/14, 11:53 AM, Robert P. J. Day wrote: > On Tue, 22 Jul 2014, Christopher Larson wrote: > >> >> On Tue, Jul 22, 2014 at 9:36 AM, Robert P. J. Day wrote: >> quite possibly another silly question, but i'm perusing poky's >> version of bitbake.conf and i see this: >> >> DEPLOY_DIR ?= "${TMPDIR}/deploy" >> DEPLOY_DIR_TAR = "${DEPLOY_DIR}/tar" >> DEPLOY_DIR_IPK = "${DEPLOY_DIR}/ipk" >> DEPLOY_DIR_RPM = "${DEPLOY_DIR}/rpm" >> DEPLOY_DIR_DEB = "${DEPLOY_DIR}/deb" >> DEPLOY_DIR_IMAGE ?= "${DEPLOY_DIR}/images/${MACHINE}" >> DEPLOY_DIR_TOOLS = "${DEPLOY_DIR}/tools" >> >> now, what is the value of using "?=" to set DEPLOY_DIR_IMAGE, rather >> than just "=". i know what "?=" represents, but i normally expect to >> see it in a context where someone might have set it earlier to some >> other value, but this is in bitbake.conf, before any of the "include" >> or "require" directives to pull in any of the other .conf files. so in >> the midst of all those other DEPLOY_DIR_* hard assignments, why is the >> images directory a conditional install? >> >> >> s/install/define/ > > um, quite so. :-P > >> If there's a ?= done before any includes in bitbake.conf, either its >> position in the file has changed, or it's set that way to allow the >> user to add those variables to the env whitelist and set them in the >> environment, as the env is set before bitbake.conf is parsed. > > ah, gotcha. so the obvious question is, who decides which variables > merit this sort of behaviour and which don't? why two variables out of > the DEPLOY_DIR_* variables and not the rest? seems sort of arbitrary. Who, whoever sends patches with a need. I know I've used both the DEPLOY_DIR and DEPLOY_DIR_IMAGE before to simplify a few things on the command line.. (but I don't use them regularly). The others being based on those have not caused me problems the few times I've wanted to override it from the command line. --Mark > rday > > >