Re: Which behavior is expected of $(shell )

[Changqing Li]

Add more info:

For make 4.3:

$make KBUILD_OUTPUT=test

KBUILD_OUTPUT in shell is

KBUILD_OUTPUT is test

For make 4.4:

$make KBUILD_OUTPUT=test

KBUILD_OUTPUT in shell is test

KBUILD_OUTPUT is test


On 11/22/22 11:12, Changqing Li wrote:
> Hi,
>
> Here is the Makefile:
>
> KBUILD_OUTPUT =
> defs := $(shell echo $$KBUILD_OUTPUT)
> all:
>         @echo "KBUILD_OUTPUT in shell is $(defs)"
>         @echo "KBUILD_OUTPUT is $(KBUILD_OUTPUT)"
>
>
> 1.  For make version 4.3
>
> $ KBUILD_OUTPUT=test make
>
> KBUILD_OUTPUT in shell is test
>
> KBUILD_OUTPUT is
>
>
> 2.  For make version 4.4
>
> $ KBUILD_OUTPUT=test make
>
> KBUILD_OUTPUT in shell is
>
> KBUILD_OUTPUT is
>
>
> Here is what the make manual says,
>
> 6.10 Variables from the Environment
>
> - However, an explicit assignment in the makefile, or with a command 
> argument, overrides the environment.
>
> - Note this is not totally reliable; some makefiles set CFLAGS 
> explicitly and therefore are not affected by the value in the 
> environment.
>
>
> I think the behavior of 4.4 is aligned with doc, if KBUILD_OUTPUT is 
> explicit set in Makefile,   in $(shell) , it should also use the value 
> set in Makefile, not still use
>
> the value in shell environment like what 4.3  done. But I don't find 
> which commit or bug ID is for fixing this issue,  so I send this mail 
> to double check with the
>
> exports at this. Thanks a lot.
>
>
> Best regards
>
> Changqing