rtems_xxxx_ident() does not support global search for all objects in the classic API

[Andrei Dimitrief-Jianu]

On Tue, Oct 9, 2012 at 6:36 PM, Joel Sherrill <joel.sherrill at oarcorp.com> wrote:
> On 10/9/2012 4:47 PM, Andrei Dimitrief-Jianu wrote:
>>
>> Hello,
>>
>> Below are two different implementations for rtems_xxxx_ident()
>> directive, one for semaphores and the second for barriers.
>>
>> rtems_status_code rtems_semaphore_ident(
>>    rtems_name  name,
>>    uint32_t    node,
>>    rtems_id   *id
>> )
>> {
>>    Objects_Name_or_id_lookup_errors  status;
>>
>>    status = _Objects_Name_to_id_u32( &_Semaphore_Information, name, node,
>> id );
>>
>>    return _Status_Object_name_errors_to_status[ status ];
>> }
>>
>> rtems_status_code rtems_barrier_ident(
>>    rtems_name  name,
>>    rtems_id   *id
>> )
>> {
>>    Objects_Name_or_id_lookup_errors  status;
>>
>>    status = _Objects_Name_to_id_u32( &_Barrier_Information, name,
>> OBJECTS_SEARCH_LOCAL_NODE, id );
>>
>>    return _Status_Object_name_errors_to_status[ status ];
>> }
>>
>> Anyone can explain why for barriers the search is done only on the
>> local node? Was it simply an implementation choice? Any other reason
>> for that?
>
> It is much simpler than you think. If the Object Class supports remote
> operations
> (e.g., global attribute on create and helpers internally), then it has the
> three argument
> form. Otherwise it takes the two argument form.
>
> Timers and Rate Monotonic Periods are strictly local. Two argument form.
>
> Barriers COULD be global but don't implement that so they use the two
> argument form.
>
> In general terms, only the objects originally required to be global by the
> RTEID/ORKID specification support global operations. The development and
> testing effort has never been put into adding global support on more recent
> Object classes even when it logically could make sense to support it.

That makes sense.

What I would like to ask is: would it make sense for an event flag
manager to support
global operations?


>>
>>
>> Thanks!
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>> rtems-devel at rtems.org
>> http://www.rtems.org/mailman/listinfo/rtems-devel
>
>
>
> --
> Joel Sherrill, Ph.D.             Director of Research & Development
> joel.sherrill at OARcorp.com        On-Line Applications Research
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>