user extensions private data in TCB question

Chris Johns chrisj at
Tue Dec 6 00:17:29 UTC 2005

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 ?

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 ?


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