Messages in this thread | | | From | Andreas Schwab <> | Subject | Re: [PATCH v3 bpf-next 01/14] samples: bpf: makefile: fix HDR_PROBE "echo" | Date | Mon, 16 Sep 2019 23:35:44 +0200 |
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On Sep 16 2019, Andrii Nakryiko <andrii.nakryiko@gmail.com> wrote:
> On Mon, Sep 16, 2019 at 3:59 AM Ivan Khoronzhuk > <ivan.khoronzhuk@linaro.org> 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 <ivan.khoronzhuk@linaro.org> >> --- >> 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.
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, schwab@linux-m68k.org GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510 2552 DF73 E780 A9DA AEC1 "And now for something completely different."
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