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

From	Michal Marek <mmarek@suse.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH v2] Kbuild: tiny correction on `make help`
Date	2017-06-14 09:40 +0200
Message-ID	<tSb4e-2hd-11@gated-at.bofh.it> (permalink)
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Dne 14.6.2017 v 09:08 Cao jin napsal(a):
> 
> 
> On 06/14/2017 09:15 AM, Masahiro Yamada wrote:
>> 2017-06-13 18:52 GMT+09:00 Cao jin <caoj.fnst@cn.fujitsu.com>:
>>> 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.

Well, it more than three years ago. But yes, I believe that was the
intention:

make --foo=s

x$(MAKEFLAGS) => x --foo=s
$(firstword x$(MAKEFLAGS)) => x

Michal

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Re: [PATCH v2] Kbuild: tiny correction on `make help` Cao jin <caoj.fnst@cn.fujitsu.com> - 2017-06-13 12:00 +0200
  Re: [PATCH v2] Kbuild: tiny correction on `make help` Masahiro Yamada <yamada.masahiro@socionext.com> - 2017-06-14 03:20 +0200
    Re: [PATCH v2] Kbuild: tiny correction on `make help` Cao jin <caoj.fnst@cn.fujitsu.com> - 2017-06-14 09:10 +0200
      Re: [PATCH v2] Kbuild: tiny correction on `make help` Michal Marek <mmarek@suse.com> - 2017-06-14 09:40 +0200

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