From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Authentication-Results: lists.ozlabs.org; spf=none (no SPF record) smtp.mailfrom=linux.intel.com (client-ip=192.55.52.115; helo=mga14.intel.com; envelope-from=adrian.ambrozewicz@linux.intel.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=linux.intel.com Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 49r9cP2hbKzDq94 for ; Mon, 22 Jun 2020 23:44:03 +1000 (AEST) IronPort-SDR: oG/5jv3zNcPsR4ldiR+XG1fxEuAWbD+Y2dCBcGS9jQBSPUWkQormm7tUe3Qh8nqmH4D7/DoBBY bBJA9JSMl7bg== X-IronPort-AV: E=McAfee;i="6000,8403,9659"; a="142807977" X-IronPort-AV: E=Sophos;i="5.75,267,1589266800"; d="scan'208";a="142807977" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Jun 2020 06:44:00 -0700 IronPort-SDR: k9wvGlncfMLW0iH7aITgCfzps9NySIYsWwNi3AniyEZwVdGq7NJ7r9rvBrC3nqT9/BkC29AHod Q79AabZ3qegg== X-IronPort-AV: E=Sophos;i="5.75,267,1589266800"; d="scan'208";a="451840293" Received: from aambroze-mobl1.ger.corp.intel.com (HELO [10.213.10.18]) ([10.213.10.18]) by orsmga005-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Jun 2020 06:43:59 -0700 Subject: Re: about virtual variable To: "zhouyuanqing8@outlook.com" , openbmc Cc: "uperic@163.com" References: From: =?UTF-8?Q?Adrian_Ambro=c5=bcewicz?= Message-ID: Date: Mon, 22 Jun 2020 15:43:55 +0200 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.9.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=windows-1252; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-BeenThere: openbmc@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Development list for OpenBMC List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 22 Jun 2020 13:44:06 -0000 I feel rude for pointing out link to StackOverflow, but this guy really nailed it when it comes to easy explanation of 'virtual/' variable namespace :) https://stackoverflow.com/a/37823742/8226884 W dniu 6/22/2020 o 14:48, zhouyuanqing8@outlook.com pisze: > Hi everyone, > >      I would like to ask, is virtual a variable defined by bitbake? I > did not find it in the bitbake manual. What is the use of the virtual > variable? What would be the problem without this variable? > > > 2.4. Preferences¶ > > > The|PROVIDES|list is only part of the solution for figuring out a > target's recipes. Because targets might have multiple providers, BitBake > needs to prioritize providers by determining provider preferences. > > A common example in which a target has multiple providers is > "virtual/kernel", which is on the|PROVIDES|list for each kernel recipe. > Each machine often selects the best kernel provider by using a line > similar to the following in the machine configuration file: > > PREFERRED_PROVIDER_virtual/kernel = "linux-yocto" > >