[dpdk-dev] [PATCH v2 1/6] lib/eal: add a common wrapper for restricted pointers

[David Marchand]

On Mon, Jul 6, 2020 at 9:50 AM Joyce Kong <joyce.kong at arm.com> wrote:
>
> The 'restrict' keyword is recognized in C99, while type qulifier
> '__restrict' compiles ok in C with all language levels. This patch
> is to add a wrapper defining '__rte_restrict' with 'restrict' and
> '__restrict' to be supported by all compilers.
>
> Signed-off-by: Joyce Kong <joyce.kong at arm.com>
> ---
>  lib/librte_eal/include/rte_common.h | 10 ++++++++++
>  1 file changed, 10 insertions(+)
>
> diff --git a/lib/librte_eal/include/rte_common.h b/lib/librte_eal/include/rte_common.h
> index 0843ce69e..cda32c056 100644
> --- a/lib/librte_eal/include/rte_common.h
> +++ b/lib/librte_eal/include/rte_common.h
> @@ -103,6 +103,16 @@ typedef uint16_t unaligned_uint16_t;
>   */
>  #define __rte_unused __attribute__((__unused__))
>
> +/**
> + * Define a wrapper for restricted pointers which can be supported
> + * by all compilers.
> + */
> +#if __STDC_VERSION__ >= 199901
> +#define __rte_restrict restrict
> +#else
> +#define __rte_restrict __restrict
> +#endif
> +
>  /**
>   * definition to mark a variable or function parameter as used so
>   * as to avoid a compiler warning
> --
> 2.27.0
>

This triggers a build error on Centos 7 as reported by the CI.
I suppose the following would do the trick, though it is untested:

/**
 * Define a wrapper for restricted pointers which can be supported
 * by all compilers.
 */
#if !defined(__STDC_VERSION__) || __STDC_VERSION__ < 199901L
#define __rte_restrict __restrict
#else
#define __rte_restrict restrict
#endif


-- 
David Marchand