alarm / setitimer question and serial record communication

Joel Sherrill <> joel.sherrill at
Wed Sep 22 15:22:43 UTC 2004

Peter Dufault wrote:
> On Sep 22, 2004, at 9:12 AM, Joel Sherrill <joel at> wrote:
>> My answer in cases like this is always to fix the RTEMS implementation
>> to match the expected standard behavior.   Provide test case and
>> documentation updates.
> I agree, but I'm surprised "alarm()" doesn't seem to interrupt the 
> thread.  Am I missing something or is that how it is?

Right now, that's how it is.

The read() isn't implemented using an interruptible blocking operation.
Classic semaphores/mutexes by default have non-interruptible blocking.
Given their use in key parts of the system infrastructure, an option
might be to add an per-instance attribute making the blocking on that
particular one interruptible.

> Peter
> Peter Dufault
> HD Associates, Inc.

Joel Sherrill, Ph.D.             Director of Research & Development
joel at                 On-Line Applications Research
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