user extensions private data in TCB question

Till Straumann strauman at
Tue Dec 6 01:42:19 UTC 2005

Chris Johns wrote:

> Till Straumann wrote:
>> How does a user extension determine it's slot/pointer
>> in the TCB extension area -- is 'rtems_index(extension_id)'
>> the standard method?
> Yes as far as I know. You need the extension's id to obtain the index.
>> If so:
>> How can an 'initial' user extension (i.e., one that was
>> created during rtems_initialize_executive_early())
>> determine the slot number it owns in the 'extensions'
>> array of the TCB?
> Could you be a little more specific ?

Besides being created (rtems_extension_create()),
extensions can also be added to the configuration table
case, I don't see how these extensions get an index and


> An extension should have a name and so you should be able to obtain 
> the id and therefore the index.
>>  From scanning through the sources, it seems that
>> initial extensions don't even have a slot for private
>> data in the TCB -- is that true? [if so: bummer!].
> What source/extensions are you referring to ?
> Chris

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