Re: [PATCH v3 bpf-next 01/14] samples: bpf: makefile: fix HDR_PROBE "echo"
On Mon, Sep 16, 2019 at 2:35 PM Andreas Schwab wrote:
>
> On Sep 16 2019, Andrii Nakryiko wrote:
>
> > On Mon, Sep 16, 2019 at 3:59 AM Ivan Khoronzhuk
> > 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
> >> ---
> >> 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 \n struct list_head {
> >> int a; }; int main() { return 0; }" | \
> >> +HDR_PROBE := $(shell printf "\#include \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.
>
> From the NEWS of make 4.3:
>
> * WARNING: Backward-incompatibility!
> Number signs (#) appearing inside a macro reference or function invocation
> no longer introduce comments and should not be escaped with backslashes:
> thus a call such as:
> foo := $(shell echo '#')
> is legal. Previously the number sign needed to be escaped, for example:
> foo := $(shell echo '\#')
> Now this latter will resolve to "\#". If you want to write makefiles
> portable to both versions, assign the number sign to a variable:
> H := \#
> foo := $(shell echo '$H')
> This was claimed to be fixed in 3.81, but wasn't, for some reason.
> To detect this change search for 'nocomment' in the .FEATURES variable.
>
> Andreas.
Oh, subtle... Thanks for explaining!
>
> --
> Andreas Schwab, sch...@linux-m68k.org
> GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510 2552 DF73 E780 A9DA AEC1
> "And now for something completely different."
Re: [PATCH v3 bpf-next 01/14] samples: bpf: makefile: fix HDR_PROBE "echo"
On Sep 16 2019, Andrii Nakryiko wrote:
> On Mon, Sep 16, 2019 at 3:59 AM Ivan Khoronzhuk
> 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
>> ---
>> 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 \n struct list_head {
>> int a; }; int main() { return 0; }" | \
>> +HDR_PROBE := $(shell printf "\#include \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.
>From the NEWS of make 4.3:
* WARNING: Backward-incompatibility!
Number signs (#) appearing inside a macro reference or function invocation
no longer introduce comments and should not be escaped with backslashes:
thus a call such as:
foo := $(shell echo '#')
is legal. Previously the number sign needed to be escaped, for example:
foo := $(shell echo '\#')
Now this latter will resolve to "\#". If you want to write makefiles
portable to both versions, assign the number sign to a variable:
H := \#
foo := $(shell echo '$H')
This was claimed to be fixed in 3.81, but wasn't, for some reason.
To detect this change search for 'nocomment' in the .FEATURES variable.
Andreas.
--
Andreas Schwab, sch...@linux-m68k.org
GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510 2552 DF73 E780 A9DA AEC1
"And now for something completely different."
Re: [PATCH v3 bpf-next 01/14] samples: bpf: makefile: fix HDR_PROBE "echo"
On Mon, Sep 16, 2019 at 01:13:23PM -0700, Andrii Nakryiko wrote:
On Mon, Sep 16, 2019 at 3:59 AM Ivan Khoronzhuk
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
---
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 \n struct list_head { int a; };
int main() { return 0; }" | \
+HDR_PROBE := $(shell printf "\#include \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) $(KBUILD_HOSTCFLAGS) -x c - -o /dev/null 2>/dev/null && \
echo okay)
--
2.17.1
--
Regards,
Ivan Khoronzhuk
Re: [PATCH v3 bpf-next 01/14] samples: bpf: makefile: fix HDR_PROBE "echo"
On Mon, Sep 16, 2019 at 3:59 AM Ivan Khoronzhuk
wrote:
>
> echo should be replaced with echo -e to handle '\n' correctly, but
> instead, replace it with printf as some systems can't handle echo -e.
>
> Signed-off-by: Ivan Khoronzhuk
> ---
> samples/bpf/Makefile | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
> index 1d9be26b4edd..f50ca852c2a8 100644
> --- a/samples/bpf/Makefile
> +++ b/samples/bpf/Makefile
> @@ -201,7 +201,7 @@ endif
>
> # Don't evaluate probes and warnings if we need to run make recursively
> ifneq ($(src),)
> -HDR_PROBE := $(shell echo "\#include \n struct list_head {
> int a; }; int main() { return 0; }" | \
> +HDR_PROBE := $(shell printf "\#include \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.
> $(HOSTCC) $(KBUILD_HOSTCFLAGS) -x c - -o /dev/null 2>/dev/null && \
> echo okay)
>
> --
> 2.17.1
>
[PATCH v3 bpf-next 01/14] samples: bpf: makefile: fix HDR_PROBE "echo"
echo should be replaced with echo -e to handle '\n' correctly, but
instead, replace it with printf as some systems can't handle echo -e.
Signed-off-by: Ivan Khoronzhuk
---
samples/bpf/Makefile | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
index 1d9be26b4edd..f50ca852c2a8 100644
--- a/samples/bpf/Makefile
+++ b/samples/bpf/Makefile
@@ -201,7 +201,7 @@ endif
# Don't evaluate probes and warnings if we need to run make recursively
ifneq ($(src),)
-HDR_PROBE := $(shell echo "\#include \n struct list_head { int
a; }; int main() { return 0; }" | \
+HDR_PROBE := $(shell printf "\#include \n struct list_head {
int a; }; int main() { return 0; }" | \
$(HOSTCC) $(KBUILD_HOSTCFLAGS) -x c - -o /dev/null 2>/dev/null && \
echo okay)
--
2.17.1
