Re: [dpdk-dev] [PATCH v2 10/10] enforce __rte_experimental at the start of symbol declarations

[Thomas Monjalon <thomas@monjalon.net>]

29/06/2019 13:58, David Marchand:
> Special mention for rte_mbuf_data_addr_default():
> 
> There is either a bug or a (not yet understood) issue with gcc.
> gcc won't drop this inline when unused and rte_mbuf_data_addr_default()
> calls rte_mbuf_buf_addr() which itself is experimental.
> This results in a build warning when not accepting experimental apis
> from sources just including rte_mbuf.h.
> 
> For this specific case, we hide the call to rte_mbuf_buf_addr() under
> the ALLOW_EXPERIMENTAL_API flag.
[...]
> -static inline char * __rte_experimental
> -rte_mbuf_data_addr_default(struct rte_mbuf *mb)
> +__rte_experimental
> +static inline char *
> +rte_mbuf_data_addr_default(struct rte_mbuf *mb __rte_unused)
>  {
> +	/* gcc complains about calling this experimental function even
> +	 * when not using it. Hide it with ALLOW_EXPERIMENTAL_API.
> +	 */
> +#ifdef ALLOW_EXPERIMENTAL_API
>  	return rte_mbuf_buf_addr(mb, mb->pool) + RTE_PKTMBUF_HEADROOM;
> +#else
> +	return NULL;
> +#endif
>  }

Doxygen is confused by having __rte_unused at the end:

lib/librte_mbuf/rte_mbuf.h:876: warning:
	argument 'mb' of command @param is not found in the argument list of
	rte_mbuf_data_addr_default(struct rte_mbuf *mb __rte_unused)
lib/librte_mbuf/rte_mbuf.h:889: warning:
	The following parameters of
	rte_mbuf_data_addr_default(struct rte_mbuf *mb __rte_unused)
	are not documented:
		parameter '__rte_unused'

I move __rte_unused at the beginning while merging.