Re: Which behavior is expected of $(shell )

On 11/22/22 12:08, Paul Smith wrote:
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> On Tue, 2022-11-22 at 11:12 +0800, Changqing Li wrote:
>> Here is what the make manual says,
>>
>> 6.10 Variables from the Environment
> It's not really related to this section.  It's related to how the shell
> function works.  From that section of the manual we see:
>
> | All variables that are marked as export will also be passed to the
> | shell started by the shell function.
>
> In your example, KBUILD_OUTPUT is coming from the environment, and all
> variables imported from the environment automatically exported.  So,
> the value of the KBUILD_OUTPUT variable set in the makefile is exported
> to the shell function.
>
> However, this behavior is new in GNU make 4.4.
>
>> 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.
> See this from the NEWS file for GNU make 4.4:
>
> https://git.savannah.gnu.org/cgit/make.git/tree/NEWS?h=4.4&id=ed493f6c9116cc217b99c2cfa6a95f15803235a2#n74
>
>> * WARNING: Backward-incompatibility!
>>    Previously makefile variables marked as export were not exported to commands
>>    started by the $(shell ...) function.  Now, all exported variables are
>>    exported to $(shell ...).
> This is the reason for the difference in behavior you see.

Thanks a lot.

Changqing