From mboxrd@z Thu Jan  1 00:00:00 1970
From: Ferruh Yigit <ferruh.yigit@intel.com>
Subject: Re: [PATCH v8 01/25] eal: define macro container_of
Date: Mon, 29 Aug 2016 17:43:35 +0100
Message-ID: <57C46637.3060707@intel.com>
References: <1466510566-9240-1-git-send-email-shreyansh.jain@nxp.com>
 <1472219823-29486-1-git-send-email-shreyansh.jain@nxp.com>
 <1472219823-29486-2-git-send-email-shreyansh.jain@nxp.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=windows-1252
Content-Transfer-Encoding: 7bit
Cc: viktorin@rehivetech.com, david.marchand@6wind.com,
 thomas.monjalon@6wind.com, hemant.agrawal@nxp.com
To: Shreyansh Jain <shreyansh.jain@nxp.com>, dev@dpdk.org
Return-path: <dev-bounces@dpdk.org>
Received: from mga03.intel.com (mga03.intel.com [134.134.136.65])
 by dpdk.org (Postfix) with ESMTP id 279B829D1
 for <dev@dpdk.org>; Mon, 29 Aug 2016 18:43:40 +0200 (CEST)
In-Reply-To: <1472219823-29486-2-git-send-email-shreyansh.jain@nxp.com>
List-Id: patches and discussions about DPDK <dev.dpdk.org>
List-Unsubscribe: <http://dpdk.org/ml/options/dev>,
 <mailto:dev-request@dpdk.org?subject=unsubscribe>
List-Archive: <http://dpdk.org/ml/archives/dev/>
List-Post: <mailto:dev@dpdk.org>
List-Help: <mailto:dev-request@dpdk.org?subject=help>
List-Subscribe: <http://dpdk.org/ml/listinfo/dev>,
 <mailto:dev-request@dpdk.org?subject=subscribe>
Errors-To: dev-bounces@dpdk.org
Sender: "dev" <dev-bounces@dpdk.org>

On 8/26/2016 2:56 PM, Shreyansh Jain wrote:
> Signed-off-by: Jan Viktorin <viktorin@rehivetech.com>
> Signed-off-by: Shreyansh Jain <shreyansh.jain@nxp.com>
> ---
>  lib/librte_eal/common/include/rte_common.h | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
> 
> diff --git a/lib/librte_eal/common/include/rte_common.h b/lib/librte_eal/common/include/rte_common.h
> index 332f2a4..a9b6792 100644
> --- a/lib/librte_eal/common/include/rte_common.h
> +++ b/lib/librte_eal/common/include/rte_common.h
> @@ -322,6 +322,22 @@ rte_bsf32(uint32_t v)
>  #define offsetof(TYPE, MEMBER)  __builtin_offsetof (TYPE, MEMBER)
>  #endif
>  
> +/**
> + * Return pointer to the wrapping struct instance.
> + * Example:
> + *
> + *  struct wrapper {
> + *      ...
> + *      struct child c;
> + *      ...
> + *  };
> + *
> + *  struct child *x = obtain(...);
> + *  struct wrapper *w = container_of(x, struct wrapper, c);
> + */
> +#define container_of(p, type, member) \
> +	((type *) (((char *) (p)) - offsetof(type, member)))
> +
>  #define _RTE_STR(x) #x
>  /** Take a macro value and get a string version of it */
>  #define RTE_STR(x) _RTE_STR(x)
> 

This gives compilation error for mlx5, because the libraries mlx depends
defines same macro:
.../rte_common.h:338:9: error: 'container_of' macro redefined
/usr/include/infiniband/verbs.h:77:9: note: previous definition is here

Does it make sense to protect macro with
#ifndef container_of
...
#endif

OR

add a dpdk prefix?


Regards,
ferruh