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Subject: Re: [PATCH] selftests: use LDLIBS for libraries instead of LDFLAGS
To:     Dmitry Safonov <dima@arista.com>
Cc:     linux-kselftest@vger.kernel.org, avagin@gmail.com,
        linux-kernel@vger.kernel.org,
        Dmitry Safonov <0x7f454c46@gmail.com>, shuah <shuah@kernel.org>
References: <20200212140040.126747-1-dima@arista.com>
From:   shuah <shuah@kernel.org>
Message-ID: <db01c4e9-c236-3847-f812-943e4442f048@kernel.org>
Date:   Wed, 12 Feb 2020 11:15:48 -0700
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On 2/12/20 7:00 AM, Dmitry Safonov wrote:
> While building selftests, the following errors were observed:
>> tools/testing/selftests/timens'
>> gcc -Wall -Werror -pthread  -lrt -ldl  timens.c  -o tools/testing/selftests/timens/timens
>> /usr/bin/ld: /tmp/ccGy5CST.o: in function `check_config_posix_timers':
>> timens.c:(.text+0x65a): undefined reference to `timer_create'
>> collect2: error: ld returned 1 exit status
> 
> Quoting commit 870f193d48c2 ("selftests: net: use LDLIBS instead of
> LDFLAGS"):
> 
> The default Makefile rule looks like:
> 
> $(CC) $(CFLAGS) $(LDFLAGS) $@ $^ $(LDLIBS)
> 
> When linking is done by gcc itself, no issue, but when it needs to be passed
> to proper ld, only LDLIBS follows and then ld cannot know what libs to link
> with.
> 
> More detail:
> https://www.gnu.org/software/make/manual/html_node/Implicit-Variables.html
> 
> LDFLAGS
> Extra flags to give to compilers when they are supposed to invoke the linker,
> ‘ld’, such as -L. Libraries (-lfoo) should be added to the LDLIBS variable
> instead.
> 
> LDLIBS
> Library flags or names given to compilers when they are supposed to invoke the
> linker, ‘ld’. LOADLIBES is a deprecated (but still supported) alternative to
> LDLIBS. Non-library linker flags, such as -L, should go in the LDFLAGS
> variable.
> 
> While at here, correct other selftests, not only timens ones.
> 
> Reported-by: Shuah Khan <skhan@kernel.org>
> Signed-off-by: Dmitry Safonov <dima@arista.com>
> ---
>   tools/testing/selftests/futex/functional/Makefile | 2 +-
>   tools/testing/selftests/net/Makefile              | 4 ++--
>   tools/testing/selftests/rtc/Makefile              | 2 +-
>   tools/testing/selftests/timens/Makefile           | 2 +-
>   4 files changed, 5 insertions(+), 5 deletions(-)
> 


Looks good. Thanks for fixing it quickly.

Please split these into 4 patches and send one for each test.

For timens:

Tested-by: Shuah Khan <skhan@linuxfoundation.org>

thanks,
-- Shuah