From mboxrd@z Thu Jan 1 00:00:00 1970 From: Adrien Mazarguil Subject: Re: [PATCH v3 2/4] ethdev: move error checking macros to header Date: Wed, 4 Nov 2015 16:25:21 +0100 Message-ID: <20151104152521.GS3518@6wind.com> References: <1441811374-28984-1-git-send-email-bruce.richardson@intel.com> <1446552059-5446-1-git-send-email-bruce.richardson@intel.com> <1446552059-5446-3-git-send-email-bruce.richardson@intel.com> <4698587.GS9blBozDC@xps13> <20151104102418.GN3518@6wind.com> <20151104141050.GA19636@bricha3-MOBL3> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: dev@dpdk.org To: Bruce Richardson Return-path: Received: from mail-wm0-f43.google.com (mail-wm0-f43.google.com [74.125.82.43]) by dpdk.org (Postfix) with ESMTP id ECF558E7A for ; Wed, 4 Nov 2015 16:25:41 +0100 (CET) Received: by wmff134 with SMTP id f134so44468042wmf.0 for ; Wed, 04 Nov 2015 07:25:41 -0800 (PST) Content-Disposition: inline In-Reply-To: <20151104141050.GA19636@bricha3-MOBL3> 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 Wed, Nov 04, 2015 at 02:10:50PM +0000, Bruce Richardson wrote: > On Wed, Nov 04, 2015 at 11:24:18AM +0100, Adrien Mazarguil wrote: > > On Wed, Nov 04, 2015 at 02:19:36AM +0100, Thomas Monjalon wrote: > > > 2015-11-03 12:00, Bruce Richardson: > > > > Move the function ptr and port id checking macros to the header file, so > > > > that they can be used in the static inline functions there. In doxygen > > > > comments, mark them as for internal use only. > > > [...] > > > > +/** > > > > + * @internal > > > > + * Macro to print a message if in debugging mode > > > > + */ > > > > +#ifdef RTE_LIBRTE_ETHDEV_DEBUG > > > > +#define RTE_PMD_DEBUG_TRACE(fmt, args...) \ > > > > + RTE_LOG(ERR, PMD, "%s: " fmt, __func__, ## args) > > > > +#else > > > > +#define RTE_PMD_DEBUG_TRACE(fmt, args...) > > > > +#endif > > > > > > It does not compile because Mellanox drivers are pedantic: > > > > > > In file included from /home/thomas/projects/dpdk/dpdk/drivers/net/mlx4/mlx4.c:78:0: > > > /home/thomas/projects/dpdk/dpdk/x86_64-native-linuxapp-gcc-shared-next/include/rte_ethdev.h: At top level: > > > /home/thomas/projects/dpdk/dpdk/x86_64-native-linuxapp-gcc-shared-next/include/rte_ethdev.h:933:38: error: ISO C does not permit named variadic macros [-Werror=variadic-macros] > > > #define RTE_PMD_DEBUG_TRACE(fmt, args...) \ > > > > I suggest something like the following definitions as a pedantic-proof and > > standard compliant method (one drawback being that it cannot be done with a > > single macro), see PMD_DRV_LOG() in drivers/net/mlx5/mlx5_utils.h which also > > automatically appends a line feed: > > > > #ifdef RTE_LIBRTE_ETHDEV_DEBUG > > > > #define STRIP(a, b) a > > #define OPAREN ( > > #define CPAREN ) > > #define COMMA , > > > > #define RTE_PMD_DEBUG_TRACE(...) \ > > RTE_PMD_DEBUG_TRACE_(__VA_ARGS__ STRIP OPAREN, CPAREN) > > > > #define RTE_PMD_DEBUG_TRACE_(fmt, ...) \ > > RTE_PMD_DEBUG_TRACE__(fmt COMMA __func__, __VA_ARGS__) > > > > #define RTE_PMD_DEBUG_TRACE__(...) \ > > RTE_LOG(ERR, PMD, "%s: " __VA_ARGS__) > > > > #else /* RTE_LIBRTE_ETHDEV_DEBUG */ > > > > #define RTE_PMD_DEBUG_TRACE(...) > > > > #endif /* RTE_LIBRTE_ETHDEV_DEBUG */ > > > > STRIP() and other helper macros are used to manage the dangling comma issue > > when __VA_ARGS__ is empty as in the first call below: > > > > RTE_PMD_DEBUG_TRACE("foo\n"); > > RTE_PMD_DEBUG_TRACE("foo %u\n", 42); > > > > -- > > Adrien Mazarguil > > 6WIND > > Is this really the best way around this? It looks like a lot more complicated > than the original solution. Do we really need to support the -pedantic flag > in our header files? I know you didn't ask me directly but I think we should, at least for exposed/installed headers. What we do internally does not matter, but we cannot prevent user applications from adding -pedantic if they want to. The above solution is one I suggest, perhaps it can be done in a different manner if you think it's too complicated, although it's difficult using macros only. -- Adrien Mazarguil 6WIND