[dpdk-dev] [PATCH v8 01/25] eal: define macro container_of

[Ferruh Yigit]

On 8/26/2016 2:56 PM, Shreyansh Jain wrote:
> Signed-off-by: Jan Viktorin <viktorin at rehivetech.com>
> Signed-off-by: Shreyansh Jain <shreyansh.jain at 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