Mbed OS Reference | mbed_shared_queues.h Source File

 /*
  * Copyright (c) 2016-2019 ARM Limited
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *     http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
 #ifndef MBED_SHARED_QUEUES_H
 #define MBED_SHARED_QUEUES_H
 
 #include "events/EventQueue.h"
 
 namespace mbed {
 /** \addtogroup events-public-api */
 /** @{*/
 
 /**
  * Return a pointer to an EventQueue, on which normal tasks can be queued.
  *
  * All calls to this return the same EventQueue - it and its dispatch thread
  * are created on the first call to this function. The dispatch thread
  * runs at default priority (currently osPriorityNormal).
  *
  * The EventQueue returned may be used to call() Events, or to chain() other
  * EventQueues so that they are run in the same context.
  *
  * Events (or chained EventQueues) executing on the normal event queue should
  * normally take less than 10ms to execute, to avoid starving other users. As
  * such, users can expect that event latency will typically be 10ms or less,
  * but could occasionally be significantly higher if many events are queued.
  *
  * If an RTOS is not present or the configuration option
  * `events.shared-dispatch-from-application` is set to true, then this
  * does not create a dedicated dispatch thread - instead the application is
  * expected to run the EventQueue's dispatch, for example from main. This is
  * necessary for the event loop to work without an RTOS, or an RTOS system can
  * save memory by reusing the main stack.
  *
  * @note
  * mbed_event_queue is not itself IRQ safe. To use the mbed_event_queue in
  * interrupt context, you must first call `mbed_event_queue()` in threaded
  * context and store the pointer for later use.
  *
  * @return pointer to event queue
  */
 events::EventQueue *mbed_event_queue();
 
 #ifdef MBED_CONF_RTOS_PRESENT
 /**
  * Return a pointer to an EventQueue, on which small high-priority tasks can
  * be queues, such as simple deferrals from interrupt.
  *
  * All calls to this return the same EventQueue - it and its thread are
  * created on the first call to this function. The dispatch thread
  * runs at a high priority (currently osPriorityHigh).
  *
  * The EventQueue returned may be used to call() Events, or to chain() other
  * EventQueues so that they are run in the same context.
  *
  * Events (or chained EventQueues) executing on the high-priority event queue
  * should normally take less than 100us to execute, to avoid starving other
  * users. As such, users can expect that event latency will typically be 100us
  * or less, but could occasionally be significantly higher if many events are
  * queued.
  *
  * @note
  * mbed_highprio_event_queue is not itself IRQ safe. To use the
  * mbed_highprio_event_queue in interrupt context, you must first call
  * `mbed_highprio_event_queue()` in threaded context and store the pointer for
  * later use.
  *
  * @return pointer to high-priority event queue
  */
 
 events::EventQueue *mbed_highprio_event_queue();
 
 #endif // MBED_CONF_RTOS_PRESENT
 
 /** @}*/
 
 }
 
 #endif
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