Re: [dpdk-dev] [PATCH] doc: announce renaming of rte_ether_hdr fields

[Ferruh Yigit <ferruh.yigit@intel.com>]

On 5/20/2021 4:06 PM, Dmitry Kozlyuk wrote:
> 2021-05-20 15:24 (UTC+0100), Ferruh Yigit:
>> On 3/3/2021 10:51 PM, Dmitry Kozlyuk wrote:
> [...]
>>>
>>> It is not mandatory to rename `d_addr`, this is for consistency only.
>>> Naming in `rte_ether_hdr` will also resemble `rte_ipv4/6_hdr`.
>>>
>>> Workaround is to define `struct rte_ether_hdr` in such a away that
>>> it can be used with or without `s_addr` macro (as defined on Windows)
>>> This can be done for Windows only or for all platforms to save space.
>>>
>>>     #pragma push_macro("s_addr")
>>>     #ifdef s_addr
>>>     #undef s_addr
>>>     #endif
>>>
>>>     struct rte_ether_hdr {
>>>         struct rte_ether_addr d_addr; /**< Destination address. */
>>>         RTE_STD_C11
>>>         union {
>>>             struct rte_ether_addr s_addr; /**< Source address. */
>>>             struct {
>>>                 struct rte_ether_addr S_un;
>>>                 /**< MUST NOT be used directly, only via s_addr */
>>>             } S_addr;
>>>             /*< MUST NOT be used directly, only via s_addr */
>>>         };
>>>         uint16_t ether_type; /**< Frame type. */
>>>     } __rte_aligned(2);
>>>
>>>     #pragma pop_macro("s_addr")
>>>   
>>
>> What is the problem with the workaround, why we can't live with it?
>>
>> It requires an order in include files, right?
> 
> There's no problem except a tricky structure definition with fields that
> violate DPDK coding rules. It works with any include order.
> 
> Will fix typos in v3, thanks.
> 

For following case, won't compiler take 's_addr' as macro?

    #include <rte_ether.h>
    #include <winsock2.h>
    struct rte_ether_hdr eh;
    /* eh.s_addr.addr_bytes[0] = 0;