From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by dpdk.org (Postfix) with ESMTP id 3831B5683 for ; Fri, 27 Nov 2015 17:17:49 +0100 (CET) Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga101.fm.intel.com with ESMTP; 27 Nov 2015 08:16:33 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.20,352,1444719600"; d="scan'208";a="3223529" Received: from irvmail001.ir.intel.com ([163.33.26.43]) by fmsmga004.fm.intel.com with ESMTP; 27 Nov 2015 08:16:32 -0800 Received: from sivlogin002.ir.intel.com (sivlogin002.ir.intel.com [10.237.217.37]) by irvmail001.ir.intel.com (8.14.3/8.13.6/MailSET/Hub) with ESMTP id tARG13cV010664; Fri, 27 Nov 2015 16:01:03 GMT Received: from sivlogin002.ir.intel.com (localhost [127.0.0.1]) by sivlogin002.ir.intel.com with ESMTP id tARG13RD000401; Fri, 27 Nov 2015 16:01:03 GMT Received: (from fyigit@localhost) by sivlogin002.ir.intel.com with œ id tARG13Vo000396; Fri, 27 Nov 2015 16:01:03 GMT X-Authentication-Warning: sivlogin002.ir.intel.com: fyigit set sender to ferruh.yigit@intel.com using -f Date: Fri, 27 Nov 2015 16:01:03 +0000 From: Ferruh Yigit To: Thomas Monjalon Message-ID: <20151127160103.GA32227@sivlogin002.ir.intel.com> Mail-Followup-To: Thomas Monjalon , Panu Matilainen , dev@dpdk.org References: <1442608390-12537-1-git-send-email-mario.alfredo.c.arevalo@intel.com> <1442608390-12537-8-git-send-email-mario.alfredo.c.arevalo@intel.com> <5600FB8B.6070909@redhat.com> <7380042.Av6xXtCM9v@xps13> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <7380042.Av6xXtCM9v@xps13> User-Agent: Mutt/1.5.17 (2007-11-01) Cc: dev@dpdk.org Subject: Re: [dpdk-dev] [PATCH 7/7] mk: Add hierarchy-file support (linux mod) X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 27 Nov 2015 16:17:49 -0000 On Fri, Nov 27, 2015 at 04:40:51PM +0100, Thomas Monjalon wrote: > 2015-09-22 09:56, Panu Matilainen: > > On 09/18/2015 11:33 PM, Mario Carrillo wrote: > > > +MOD_DIR := $(DESTDIR)/lib/modules > > > +KERNEL_DIR := $(shell uname -r)/extra > > > > Please don't assume one is always building for the running kernel. > > Defaulting around uname -r is perfectly reasonable, but there needs to > > be a way to override it from the cli. For example rte.vars.mk has this: > > > > # can be overriden by make command line or exported environment variable > > RTE_KERNELDIR ?= /lib/modules/$(shell uname -r)/build > > For info, the ?= operator is a way to give a default value after having > included other makefiles which may set a different value. > Both ?= and := (or simply =) are overriden by the command line. > Only "override VAR =" will not be overriden by the command line. > As far as I know only "?=" assignment overridden by command line. Basic experiment: # cat Makefile A ?= a B := b C = c all: @echo $(A) $(B) $(C) ----- # make a b c # A=x B=x C=x make x b c ferruh