In my userspace POSIX program, I get a '-1' return value from sem_timedwait, even when the function succeeds.  When the function succeeds, errno is '-1' as well.  I am using this workaround at the moment:

      result = sem_timedwait(&cas_sem, &wake_time);
      if (result < 0 && errno > 0) /* errno > 0 to work around xenomai bug */
        {
          print_msg(WARN_MSG, "sem_wait returned with error code %d\n",
                    errno);
          continue;
        }

I am using xenomai 2.2.4, but I think the problem exists in other branches as well.  I believe the attached patch against the trunk should fix the problem.  Do you agree?

Thanks,

Jeff