[dpdk-dev] [RFC PATCH 1/6] eal: define container macro
Jan Blunck
jblunck at infradead.org
Thu Nov 17 13:06:49 CET 2016
On Thu, Nov 17, 2016 at 6:30 AM, Shreyansh Jain <shreyansh.jain at nxp.com> wrote:
> From: Jan Viktorin <viktorin at rehivetech.com>
>
> 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 | 18 ++++++++++++++++++
> 1 file changed, 18 insertions(+)
>
> diff --git a/lib/librte_eal/common/include/rte_common.h b/lib/librte_eal/common/include/rte_common.h
> index db5ac91..8152bd9 100644
> --- a/lib/librte_eal/common/include/rte_common.h
> +++ b/lib/librte_eal/common/include/rte_common.h
> @@ -331,6 +331,24 @@ 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);
> + */
> +#ifndef container_of
> +#define container_of(p, type, member) \
> + ((type *) (((char *) (p)) - offsetof(type, member)))
Are there any reasons why you choose to implement this in a non-type
safe way? Catching obvious bugs at compile time is in the interest of
us and our users from my point of view.
> +#endif
> +
> #define _RTE_STR(x) #x
> /** Take a macro value and get a string version of it */
> #define RTE_STR(x) _RTE_STR(x)
> --
> 2.7.4
>
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