RTEMS C User's Guide
In general, an option is built by a bitwise OR of the
desired option components. The set of valid options for the
rtems_semaphore_obtain directive are listed
in the following table:
RTEMS_WAIT - task will wait for semaphore (default)
RTEMS_NO_WAIT - task should not wait
Option values are specifically designed to be mutually exclusive,
therefore bitwise OR and addition operations are equivalent as long as
each attribute appears exactly once in the component list. An option
listed as a default is not required to appear in the list, although it is
a good programming practice to specify default options. If all defaults
are desired, the option RTEMS_DEFAULT_OPTIONS should be
specified on this call.
This example demonstrates the option parameter needed
to poll for a semaphore. The option parameter passed to the
rtems_semaphore_obtain
directive should be RTEMS_NO_WAIT.
RTEMS C User's Guide
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