Re: Re: [Xenomai-help] What returns rt_task_self in

[Philippe Gerum <rpm@xenomai.org>]

On Wed, 2006-11-22 at 15:16 +0100, M. Koehrer wrote:

> The main use case for this is that some user specific, task related data
> has to be stored. One pointer should be sufficient.
> I think, an approach that uses the Xenomai API for that is better than
> to rely on TLS or NPTL as it is unclear if related actions lead to an unwanted syscall.
> 

Think in terms of probability: what's the probability for our own local
TLS implementation to break after we missed some obscure glibc change VS
the probability for the glibc to suddently emit syscalls for
pthread_getspecific()? Because #1 is much more likely than #2, we should
rely on the regular TLS. IOW, let's not reinvent the wheel, particularly
if it's square.

> One (very ugly) approach could be to code an address into the name of the task.
> This name could be retrieved via rt_task_inquire()...
> 

Unfortunately, this would make no sense when multiple address spaces are
involved (kernel/user-space, different processes). This is why
descriptors should be seen as containers for handles, that eventually
point at some objects.

> Mathias
> 
-- 
Philippe.