| Message ID | 20190916105433.11404-2-ivan.khoronzhuk@linaro.org |
|---|---|
| State | Superseded |
| Headers | show |
| Series | samples: bpf: improve/fix cross-compilation | expand |
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."
On Mon, Sep 16, 2019 at 2:35 PM Andreas Schwab <schwab@linux-m68k.org> wrote: > > 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. Oh, subtle... Thanks for explaining! > > -- > 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."
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; }" | \ $(HOSTCC) $(KBUILD_HOSTCFLAGS) -x c - -o /dev/null 2>/dev/null && \ echo okay)
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(-) -- 2.17.1