From mboxrd@z Thu Jan 1 00:00:00 1970 From: Adrien Mazarguil Subject: Re: [PATCH v3 00/11] Fix build errors related to exported headers Date: Fri, 8 Jul 2016 17:23:04 +0200 Message-ID: <20160708152304.GH7621@6wind.com> References: <10B01822-557C-400A-A6BE-DBFF60AF90E4@intel.com> <20160708080543.GB7621@6wind.com> <577F78E9.8020705@intel.com> <20160708143512.GG7621@6wind.com> <577FBC9E.30604@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: "Wiles, Keith" , "dev@dpdk.org" To: Ferruh Yigit Return-path: Received: from mail-wm0-f48.google.com (mail-wm0-f48.google.com [74.125.82.48]) by dpdk.org (Postfix) with ESMTP id A991895FF for ; Fri, 8 Jul 2016 17:23:07 +0200 (CEST) Received: by mail-wm0-f48.google.com with SMTP id n127so15058006wme.1 for ; Fri, 08 Jul 2016 08:23:07 -0700 (PDT) Content-Disposition: inline In-Reply-To: <577FBC9E.30604@intel.com> List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" On Fri, Jul 08, 2016 at 03:45:50PM +0100, Ferruh Yigit wrote: > On 7/8/2016 3:35 PM, Adrien Mazarguil wrote: > > On Fri, Jul 08, 2016 at 02:15:37PM +0000, Wiles, Keith wrote: > >> > >>> On Jul 8, 2016, at 4:56 AM, Yigit, Ferruh wrote: > >>> > >>> On 7/8/2016 9:05 AM, Adrien Mazarguil wrote: > >>>> On Thu, Jul 07, 2016 at 06:33:17PM +0000, Wiles, Keith wrote: > >>>>> > >>>>>> On Jul 7, 2016, at 10:49 AM, Adrien Mazarguil wrote: > >>>>>> > >>>>>> DPDK uses GNU C language extensions in most of its code base. This is fine > >>>>>> for internal source files whose compilation flags are controlled by DPDK, > >>>>>> however user applications that use exported "public" headers may experience > >>>>>> compilation failures when enabling strict error/standard checks (-std and > >>>>>> -pedantic for instance). > >>>>> > >>>>> Do you try compiling these changes with CLANG and/or ICC compilers? > >>>> > >>>> clang/clang++ yes, works fine. I did not try with ICC however. > >>> > >>> I tested with icc, getting following error [1], compiler warning seems > >>> valid, but didn't investigate what in your patch cause this. > >>> > >>> [1] > >>> .../app/test/test_table_acl.c(487): error #2405: array of elements > >>> containing a flexible array member is nonstandard > >>> struct rte_pipeline_table_entry entries[5]; > >>> ^ > >>> > >>> .../app/test/test_table_acl.c(492): error #2405: array of elements > >>> containing a flexible array member is nonstandard > >>> struct rte_pipeline_table_entry entries_ptr[5]; > >> > >> I am guessing it does not like the uint8_t action_data[0] in the rte_pipeline_table_entry structure. I can see why it would be non-standard allocated on the stack in this case. Maybe a keyword like __extension__ needs to be added or pragma. > > > > Hmmm, right, a variable array cannot be embedded like that. I think a change > > in test_table_acl.c would be better. > Correct, I just wonder why not getting this same compiler warning before > your changes. > > ... I guess declaring a zero-sized array does not give the same compiler constraints as declaring a variable-sized one even though the structure has the same size in both cases. C99 does not allow it. This is probably the only difference. > > > Is that the only issue you saw? > > > Yes. OK then, prepare for v4. > >>>> Note that considering "({ ... })" is a GNU extension, compilers that do > >>>> support this syntax also support the GNU __extension__ keyword. As a result, > >>>> those that do not support this keyword most likely already cannot compile > >>>> DPDK at all. -- Adrien Mazarguil 6WIND