Subject: Re: [PATCH v3 bpf-next 01/14] samples: bpf: makefile: fix HDR_PROBE "echo"

From: Ivan Khoronzhuk <[email-masked]>
Date: Tue, 17 Sep 2019 00:22:06 +0300

On Mon, Sep 16, 2019 at 01:13:23PM -0700, Andrii Nakryiko wrote:
>On Mon, Sep 16, 2019 at 3:59 AM Ivan Khoronzhuk
><[email-masked]> wrote:
>>
>> echo should be replaced with echo -e to handle '\n' correctly, but
>> instead, replace it with printf as some systems can't handle echo -e.
>>
>> Signed-off-by: Ivan Khoronzhuk <[email-masked]>
>> ---
>>  samples/bpf/Makefile | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
>> index 1d9be26b4edd..f50ca852c2a8 100644
>> --- a/samples/bpf/Makefile
>> +++ b/samples/bpf/Makefile
>> @@ -201,7 +201,7 @@ endif
>>
>>  # Don't evaluate probes and warnings if we need to run make recursively
>>  ifneq ($(src),)
>> -HDR_PROBE := $(shell echo "\#include <linux/types.h>\n struct list_head { int a; }; int main() { return 0; }" | \
>> +HDR_PROBE := $(shell printf "\#include <linux/types.h>\n struct list_head { int a; }; int main() { return 0; }" | \
>
>printf change is fine, but I'm confused about \# at the beginning of
>the string. Not sure what was the intent, but it seems like it should
>work with just #include at the beginning.

At least no warns, but looks like should work.
Will try it in next v.

>
>>         $(HOSTCC) $(KBUILD_HOSTCFLAGS) -x c - -o /dev/null 2>/dev/null && \
>>         echo okay)
>>
>> --
>> 2.17.1
>>

-- 
Regards,
Ivan Khoronzhuk