Re: [PATCH v2] Kbuild: tiny correction on `make help`

From: Cao jin
Date: Wed Jun 14 2017 - 03:06:29 EST




On 06/14/2017 09:15 AM, Masahiro Yamada wrote:
> 2017-06-13 18:52 GMT+09:00 Cao jin <caoj.fnst@xxxxxxxxxxxxxx>:
>> Yamada-san,
>>
>> I have a question on the current top level Makefile. There are
>> following lines, I have trouble to understand "firstword x$(MAKEFLAGS)"
>> in 2nd line, why there is a 'x' there?
>>
>>
>> ifneq ($(filter 4.%,$(MAKE_VERSION)),) # make-4
>> ifneq ($(filter %s ,$(firstword x$(MAKEFLAGS))),)
>
>
> I do not understand the 'x' either.
>
> Michal suggested the code according to the following:
> https://patchwork.kernel.org/patch/3291301/
> (I hope Michal can help you.)
>

It does helps.

>
> My first guess was, it was added just in case $(MAKEFLAGS) is empty.
> Actually $(firstword ) seems to work with empty argument, though.
>

I see, I guess you are saying it was added in case there is no
single-letter flags in $(MAKEFLAGS) while it has "--debug=jobs", that
make sense to me. Thanks very much, Yamada-san.

--
Sincerely,
Cao jin