Introducing a cmp() operation

Marcus Brinkmann marcus.brinkmann at
Wed Jun 15 16:01:34 CEST 2005

At Wed, 15 Jun 2005 15:53:49 +0200,
Bernhard Kauer <kauer at> wrote:
> > Here a summary: A can not ask C to send one, because this
> > would either mean C has to make a blocking call to B, or B has to make
> > a blocking call to A _and_ trust A to forward the request to C.  B
> > really wants to make sure that it gets its own new mapping of the
> > capability from C, and not from A.
> How does it get the capability the first time?

I assume you mean how B gets the capability from A initially.

Usually A sends it to B via a request.

B could either be blocking on A, if there is mutual trust, for example
during the startup of a child process.  Or it could be a server in a
normal receive loop.

If you are asking how you get any capability initially, then that is a
much more complex protocol.  I can elaborate on that, but it is
probably not very relevant.


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