From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Wiles, Keith" Subject: Re: [PATCH v4 1/2] Simplify the ifdefs in rte.app.mk. Date: Thu, 30 Apr 2015 16:33:36 +0000 Message-ID: References: <1430321158-17805-1-git-send-email-keith.wiles@intel.com> <5541F9C1.9050701@6wind.com> <5542305D.9070505@6wind.com> <20150430162255.GA5708@bricha3-MOBL3> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Cc: "dev-VfR2kkLFssw@public.gmane.org" To: "Richardson, Bruce" Return-path: In-Reply-To: <20150430162255.GA5708@bricha3-MOBL3> Content-Language: en-US Content-ID: <7E2EAC90A210AD45903B6B9D929242A5-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org> List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces-VfR2kkLFssw@public.gmane.org Sender: "dev" On 4/30/15, 11:22 AM, "Richardson, Bruce" wrote: >On Thu, Apr 30, 2015 at 02:31:13PM +0000, Wiles, Keith wrote: >>=20 >>=20 >> On 4/30/15, 8:38 AM, "Olivier MATZ" wrote: >>=20 >> >Hi Keith, >> > >> >On 04/30/2015 03:24 PM, Wiles, Keith wrote: >> >> >> >> >> >> On 4/30/15, 4:45 AM, "Olivier MATZ" wrote: >> >> >> >>> Hi Keith, >> >>> >> >>> Thank you for submitting a clean-up. Please see some comments below. >> >>> >> >>> On 04/29/2015 05:25 PM, Keith Wiles wrote: >> >>>> Trying to simplify the ifdefs in rte.app.mk to make the code >> >>>> more readable and maintainable by moving LDLIBS variable to use >> >>>> the same style as LDLIBS-y being used in the rest of the code. >> >>>> >> >>>> Added a new variable called EXTRA_LDLIBS to be used by example apps >> >>>> instead of using LDLIBS directly. >> >>> >> >>> If I understand well, the goal of this patch is only a cleanup in >> >>> rte.app.mk, but at the end, it changes the makefile user "API", >> >>> which could probably be a problem for applications using the >> >>> dpdk makefile framework. >> >>> >> >>> Why not just having an temporary internal variable (let's say >> >>> _LDLIBS-y) that would allow to do the clean-up without modifying >> >>> the user interface? >> >>> >> >>> Also, with your patch, the approach for EXTRA_LDLIBS would be >> >>> different than CFLAGS or LDFLAGS: >> >>> - CFLAGS/LDFLAGS are in Makefiles only >> >>> - EXTRA_CFLAGS/EXTRA_LDFLAGS are prefered in command line >> >>> to add flags to the default ones >> >>> >> >>> I'm not opposed to add EXTRA_LDLIBS in addition to LDLIBS, >> >>> keeping a compatibility with existing application Makefiles. >> >> >> >> The docs for DPDK 28.3.6 states they can be used for both command >>line >> >>and >> >> Makefile, so I think I like the current solution unless everyone >>wants >> >>it >> >> as you suggested. >> >> >> >>=20 >>=20 >>>>http://dpdk.readthedocs.org/en/v2.0.0/prog_guide/dev_kit_build_system.h >>>>tm >> >>l >> > >> > From the link you have sent: >> > >> >- About CFLAGS: >> > >> >"28.3.4. Variables that Can be Set/Overridden in a Makefile Only >> >[...] >> >CFLAGS: Flags to use for C compilation. The user should use +=3D to >>append >> >data in this variable." >> > >> >nothing in 28.3.6 >> > >> > >> >- About EXTRA_CFLAGS: >> > >> >nothing in 28.3.4 >> > >> >"28.3.6. Variables that Can be Set/Overridden by the User in a Makefile >> >or Command Line >> >[...] >> >EXTRA_CFLAGS: The content of this variable is appended after CFLAGS >>when >> >compiling." >>=20 >> The point was that EXTRA_XXX can be used for command line and Makefile >>as >> it was pointed out in a previous email the assumption was EXTRA_XXX was >> only for the command line. (Just to make sure we understood EXTRA_XXX >>was >> not just for command line options.) This was the reason I sent the link >>an >> to point out using EXTRA_XXX is a much cleaner method then allowing >> someone to modify what I believe is an internal variable. > >Just beware that setting EXTRA_* flags on the commandline can override >their >values in the makefiles, and cause unexpected compilation problems. >Therefore, >it tends to be best to avoid using the EXTRA_* variables for variables >essential >to compile. For example: putting "-g -O3" in EXTRA_CFLAGS is ok, as the >if the >useroverrides those with something else things should still work, but >putting >"-I/path/to/include" would not be. On the command line and makefile you should be using +=3D and not just =3D = or you run into this problem. > >/Bruce > >=20