[ECOS] binary vs. counting semaphore and timed wait

[Nick Garnett]

David Brennan <eCos@brennanhome.cxm> writes:

> In the process of porting an application to eCos, I came across the use
> of a binary semaphore with a timed wait function.  The eCos
> Cyg_Binary_Semaphore interface does not provide this.  But it sure looks
> like the rest of the code is similar enough to the counting semaphore
> that it could be implemented very easily.  However before I do this, is
> there some particular reason this was not implemented?  I'd be very
> interested to hear if this is a bad idea.
> 

Timeouts were added to the counting semaphores because it was needed
for POSIX compatibility. Nobody needed it in the binary semaphores
until now.

If you want to add a timed wait for binary semaphores, go ahead. Make
sure you ifdef it with CYGFUN_KERNEL_THREADS_TIMER, and follow the
example of the counting semaphores. In theory it should be a fairly
simple copy-paste-edit of the counting semaphores code.

When you have it done, submit a patch on the patches list, with a
ChangeLog entry, and someone will check it over and commit it to the
repository.


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


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