[ltt-dev] [UST PATCH] Fixes container_of macro redefinition warnings

[David Goulet]

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I totally agree with you!

Stefan Hajnoczi (of QEMU) raised this concern and I wanted to do something like
you just proposed! So, very glad you came up with that comment now! Let's do this ;)

I'll resubmit soon

Cheers
David

On 10-09-23 10:27 AM, Nils Carlson wrote:
> Commente below...
> 
> On Wed, 22 Sep 2010, David Goulet wrote:
> 
>> On urcu commit 453629a9317adef5b96c3d55e4dcd98db680997a, the
>> container_of macro was moved to urcu/compiler.h. Since, multiple
>> warnings appear about redefinition
>>
> 
> I think we should consider things in a more general sense. This is a
> little bit of what I think the Qemu/KVM people were complaining about.
> 
> We are terrible namespace polluters. Ideally, when you make a library,
> you want to provide a limited set of external api's that are well defined
> and well maintained and consistent over versions. You then want to hide
> EVERYTHING else. This means that we should put some effort into hiding
> all the macros and functions that we don't want to explicity export.
> 
> So I suggest we prefix all out internal-only macros which are visible in
> global header files with __ust_. I would suggest Mathieu do the same with
> urcu. If we don't want to support the macros, then they should have a
> private namespace. I think container_of is an excellent example of this,
> we use it, but it's not ours to export.
> 
> So a NACK here. Instead, call it __ust_container_of and then fix all the
> call sites.
> 
> /Nils
> 
> 
> 
> 
>> Signed-off-by: David Goulet <david.goulet at polymtl.ca>
>> ---
>> include/ust/core.h           |    2 ++
>> include/ust/kcompat/simple.h |    3 ++-
>> 2 files changed, 4 insertions(+), 1 deletions(-)
>>
>> diff --git a/include/ust/core.h b/include/ust/core.h
>> index 0172614..d5a1f4d 100644
>> --- a/include/ust/core.h
>> +++ b/include/ust/core.h
>> @@ -141,8 +141,10 @@ static __inline__ int get_count_order(unsigned
>> int count)
>>     return order;
>> }
>>
>> +#ifndef container_of
>> #define container_of(ptr, type, member) ({                      \
>>         const typeof( ((type *)0)->member ) *__mptr = (ptr);    \
>>         (type *)( (char *)__mptr - offsetof(type,member) );})
>> +#endif /* containter_of */
>>
>> #endif /* UST_CORE_H */
>> diff --git a/include/ust/kcompat/simple.h b/include/ust/kcompat/simple.h
>> index 762d802..586b2ed 100644
>> --- a/include/ust/kcompat/simple.h
>> +++ b/include/ust/kcompat/simple.h
>> @@ -28,10 +28,11 @@
>>  * @member:    the name of the member within the struct.
>>  *
>>  */
>> +#ifndef container_of
>> #define container_of(ptr, type, member) ({            \
>>     const typeof( ((type *)0)->member ) *__mptr = (ptr);    \
>>     (type *)( (char *)__mptr - offsetof(type,member) );})
>> -
>> +#endif /* container_of */
>>
>> /* libkcompat: from rcupdate.h */
>>
>> -- 
>> 1.7.3
>>
>>
>> _______________________________________________
>> ltt-dev mailing list
>> ltt-dev at lists.casi.polymtl.ca
>> http://lists.casi.polymtl.ca/cgi-bin/mailman/listinfo/ltt-dev
>>

- -- 
David Goulet
LTTng project, DORSAL Lab.

1024D/16BD8563
BE3C 672B 9331 9796 291A  14C6 4AF7 C14B 16BD 8563
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