From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <ferruh.yigit@intel.com>
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)
Received: from orsmga001.jf.intel.com ([10.7.209.18])
 by orsmga103.jf.intel.com with ESMTP; 29 Aug 2016 09:43:38 -0700
X-ExtLoop1: 1
X-IronPort-AV: E=Sophos;i="5.30,597,1470726000"; d="scan'208";a="1021833055"
Received: from fyigit-mobl1.ger.corp.intel.com (HELO [10.237.220.32])
 ([10.237.220.32])
 by orsmga001.jf.intel.com with ESMTP; 29 Aug 2016 09:43:36 -0700
To: Shreyansh Jain <shreyansh.jain@nxp.com>, dev@dpdk.org
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>
Cc: viktorin@rehivetech.com, david.marchand@6wind.com,
 thomas.monjalon@6wind.com, hemant.agrawal@nxp.com
From: Ferruh Yigit <ferruh.yigit@intel.com>
Message-ID: <57C46637.3060707@intel.com>
Date: Mon, 29 Aug 2016 17:43:35 +0100
User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:38.0) Gecko/20100101
 Thunderbird/38.7.2
MIME-Version: 1.0
In-Reply-To: <1472219823-29486-2-git-send-email-shreyansh.jain@nxp.com>
Content-Type: text/plain; charset=windows-1252
Content-Transfer-Encoding: 7bit
Subject: Re: [dpdk-dev] [PATCH v8 01/25] eal: define macro container_of
X-BeenThere: dev@dpdk.org
X-Mailman-Version: 2.1.15
Precedence: list
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>
X-List-Received-Date: Mon, 29 Aug 2016 16:43:40 -0000

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