[ECOS] Need clarification for cyg_mbox_timed_get()

[Nick Garnett]

Jay Foster <jay.foster@systech.com> writes:

> The documentation for cyg_mbox_timed_get() states that it "will wait until
> either a message is available or until a number of clock ticks have
> occurred."
> 
> Occurred since when?
> 
> I assumed it was clock ticks occurred since the call to
> cyg_mbox_timed_get(), but it seems to behave as if it is clock ticks
> occurred since boot time (not as useful).  What is the correct behavior?
> 

As with most timeouts in eCos, the timeouts for message boxes are
absolute times rather than interval times. This is because it is easy
to synthesize an interval timeout from a API that uses an absolute
time, but it is not possible to synthesize an absolute timeout from an
API that takes an interval time.

-- 
Nick Garnett                    eCos Kernel Architect
http://www.ecoscentric.com/     The eCos and RedBoot experts


-- 
Before posting, please read the FAQ: http://ecos.sourceware.org/fom/ecos
and search the list archive: http://ecos.sourceware.org/ml/ecos-discuss