Re: [PATCH v5 15/17] kconfig: Add support for 'as-option'

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Hi Masahiro,

On 18/02/2020 00:37, Masahiro Yamada wrote:
> Hi,
> 

[...]
>>>
>>
>> Could you please elaborate a bit more?
> 
> 
> I am just not familiar with this usage of /dev/zero.
> 
> > The behavior of /dev/null is clear.
> The read/write to /dev/null is described in the standard:
> https://pubs.opengroup.org/onlinepubs/009695399/basedefs/xbd_chap10.html
> 
> I just do not know whether the write to /dev/zero is
> the defined-behavior or not.
>

Even if /dev/null is more common for this use, in linux /dev/zero has the same
behavior for what concerns the write operation. In particular all write
operations to /dev/zero succeed with no other effects.

You do not find it at the link you provided because existence of /dev/zero is
not required by POSIX as far as I know, but the behavior is standardized by
Linux ABI hence I do not think it is going to change.

Please have a look at drivers/char/mem.c +818 where the operation is defined.

Based on this I propose to put a comment on why we are not using /dev/null in
this case accordingly with what you stated in your previous email, but to leave
the rule as is.

> 
> Masahiro Yamada
> 
> 
>>
>>>
>>> Does this work?
>>>
>>> as-option = $(success, cat /dev/null | $(CC) $(CLANG_FLAGS) $(1) -c -x
>>> assembler -o /dev/null -)
>>>
>>
[...]

-- 
Regards,
Vincenzo

Attachment: pEpkey.asc
Description: application/pgp-keys


[Index of Archives]     [Linux&nblp;USB Development]     [Linux Media]     [Video for Linux]     [Linux Audio Users]     [Yosemite Secrets]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux