[dpdk-dev] [PATCH v4 25/27] eal: mark old naming as deprecated

[Burakov, Anatoly]

On 20-Jul-20 7:51 PM, Stephen Hemminger wrote:
> On Mon, 20 Jul 2020 13:32:27 +0100
> "Burakov, Anatoly" <anatoly.burakov at intel.com> wrote:
> 
>> On 18-Jul-20 3:22 AM, Stephen Hemminger wrote:
>>> On Fri, 17 Jul 2020 16:21:37 +0100
>>> "Burakov, Anatoly" <anatoly.burakov at intel.com> wrote:
>>>    
>>>> On 16-Jul-20 11:04 PM, Stephen Hemminger wrote:
>>>>> On Thu, 16 Jul 2020 14:41:41 +0100
>>>>> "Burakov, Anatoly" <anatoly.burakov at intel.com> wrote:
>>>>>       
>>>>>> On 15-Jul-20 9:29 PM, Stephen Hemminger wrote:
>>>>>>> On Wed, 15 Jul 2020 14:28:17 +0100
>>>>>>> "Burakov, Anatoly" <anatoly.burakov at intel.com> wrote:
>>>>>>>          
>>>>>>>>> -#define SKIP_MASTER	SKIP_INITIAL
>>>>>>>>> -#define CALL_MASTER	CALL_INITIAL
>>>>>>>>> +#define SKIP_MASTER _Pragma("GCC warning \"'SKIP_MASTER' is deprecated\"") SKIP_INITIAL
>>>>>>>>> +#define CALL_MASTER _Pragma("GCC warning \"'CALL_MASTER' is deprecated\"") CALL_INITIAL
>>>>>>>>
>>>>>>>> Presumably this is a generic header, should we introduce GCC-specific
>>>>>>>> things there?
>>>>>>>
>>>>>>> It works with Clang as well. Likely ICC but don't have that.
>>>>>>>          
>>>>>>
>>>>>> What about MSVC?
>>>>>>      
>>>>>
>>>>> _Pragma is C99 standard so MSVC know it.
>>>>> MSVC should ignore any pragman it doesn't understand.
>>>>>
>>>>> There is a better pragma for deprecating keywords in MSVC, but GCC and Clang don't
>>>>> understand it.
>>>>>       
>>>>
>>>> Deprecating macros sounds like something we might want to do in the
>>>> future, can't we put some macro into rte_common.h to address this? e.g.
>>>> something like
>>>>
>>>> #ifdef MSVC
>>>> #define rte_deprecated_macro _msvc_pragma_whatever()
>>>> #else
>>>> #define rte_deprecated_macro _Pragma("GCC warning ...")
>>>> #endif
>>>>
>>>> and use this macro here?
>>>
>>> It gets hard to do macro in a macro,
>>>    
>>
>> I don't have a strong opinion on this, but IMO it's certainly better
>> than having a compiler-specific things in an API header file :)
>>
> 
> I was hoping for macro volunteer?
> 
> Something like:
> #define RTE_DEPRECATED(foo) ...
> 

Oh, sure, apologies for not picking up on that :D

A bit on the ugly side, but should work:

#define __rte_deprecated_macro(val) (_Pragma("GCC warning \"'" #val "'\" 
is deprecated\"") (val))

To be used as:

#define NEW __rte_deprecated_macro(OLD)

(I feel there could be confusion between __rte_deprecated and 
RTE_DEPRECATED, so both for consistency and clarity, i believe 
"__rte_deprecated_macro" would be a better name - however, no strong 
opinion, RTE_DEPRECATED is fine by me as well)

-- 
Thanks,
Anatoly