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This makes it easier to automatically generate parts of the manager documentation in the future. Update #3993.
64 lines
2.3 KiB
ReStructuredText
64 lines
2.3 KiB
ReStructuredText
.. SPDX-License-Identifier: CC-BY-SA-4.0
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.. Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
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Operations
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==========
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Sending an Event Set
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--------------------
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The ``rtems_event_send`` directive allows a task (or an ISR) to direct an event
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set to a target task. Based upon the state of the target task, one of the
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following situations applies:
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- Target Task is Blocked Waiting for Events
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- If the waiting task's input event condition is satisfied, then the task is
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made ready for execution.
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- If the waiting task's input event condition is not satisfied, then the
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event set is posted but left pending and the task remains blocked.
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- Target Task is Not Waiting for Events
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- The event set is posted and left pending.
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Receiving an Event Set
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----------------------
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The ``rtems_event_receive`` directive is used by tasks to accept a specific
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input event condition. The task also specifies whether the request is
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satisfied when all requested events are available or any single requested event
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is available. If the requested event condition is satisfied by pending events,
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then a successful return code and the satisfying event set are returned
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immediately. If the condition is not satisfied, then one of the following
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situations applies:
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- By default, the calling task will wait forever for the event condition to be
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satisfied.
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- Specifying the ``RTEMS_NO_WAIT`` option forces an immediate return with an
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error status code.
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- Specifying a timeout limits the period the task will wait before returning
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with an error status code.
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Determining the Pending Event Set
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---------------------------------
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A task can determine the pending event set by calling the
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``rtems_event_receive`` directive with a value of ``RTEMS_PENDING_EVENTS`` for
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the input event condition. The pending events are returned to the calling task
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but the event set is left unaltered.
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Receiving all Pending Events
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----------------------------
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A task can receive all of the currently pending events by calling the
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``rtems_event_receive`` directive with a value of ``RTEMS_ALL_EVENTS`` for the
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input event condition and ``RTEMS_NO_WAIT | RTEMS_EVENT_ANY`` for the option
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set. The pending events are returned to the calling task and the event set is
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cleared. If no events are pending then the ``RTEMS_UNSATISFIED`` status code
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will be returned.
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