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<div class="title">xTaskNotify</div> </div>
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<p>task. h </p><pre>BaseType_t <a class="el" href="task_8h.html#a0d2d54fb8a64011dfbb54983e4ed06bd">xTaskNotify( TaskHandle_t xTaskToNotify, uint32_t ulValue, eNotifyAction eAction )</a>;</pre><p>configUSE_TASK_NOTIFICATIONS must be undefined or defined as 1 for this function to be available.</p>
<p>When configUSE_TASK_NOTIFICATIONS is set to one each task has its own private "notification value", which is a 32-bit unsigned integer (uint32_t).</p>
<p>Events can be sent to a task using an intermediary object. Examples of such objects are queues, semaphores, mutexes and event groups. Task notifications are a method of sending an event directly to a task without the need for such an intermediary object.</p>
<p>A notification sent to a task can optionally perform an action, such as update, overwrite or increment the task's notification value. In that way task notifications can be used to send data to a task, or be used as light weight and fast binary or counting semaphores.</p>
<p>A notification sent to a task will remain pending until it is cleared by the task calling <a class="el" href="task_8h.html#a0475fcda9718f403521c270a7270ff93">xTaskNotifyWait()</a> or <a class="el" href="task_8h.html#a66540bef602522a01a519f776e4c07d8">ulTaskNotifyTake()</a>. If the task was already in the Blocked state to wait for a notification when the notification arrives then the task will automatically be removed from the Blocked state (unblocked) and the notification cleared.</p>
<p>A task can use <a class="el" href="task_8h.html#a0475fcda9718f403521c270a7270ff93">xTaskNotifyWait()</a> to [optionally] block to wait for a notification to be pending, or <a class="el" href="task_8h.html#a66540bef602522a01a519f776e4c07d8">ulTaskNotifyTake()</a> to [optionally] block to wait for its notification value to have a non-zero value. The task does not consume any CPU time while it is in the Blocked state.</p>
<p>See <a href="http://www.FreeRTOS.org/RTOS-task-notifications.html">http://www.FreeRTOS.org/RTOS-task-notifications.html</a> for details.</p>
<dl class="params"><dt>Parameters</dt><dd>
<table class="params">
<tr><td class="paramname">xTaskToNotify</td><td>The handle of the task being notified. The handle to a task can be returned from the xTaskCreate() API function used to create the task, and the handle of the currently running task can be obtained by calling <a class="el" href="task_8h.html#a85a0f9c9f817b18686efbf8f37c72dfc">xTaskGetCurrentTaskHandle()</a>.</td></tr>
<tr><td class="paramname">ulValue</td><td>Data that can be sent with the notification. How the data is used depends on the value of the eAction parameter.</td></tr>
<tr><td class="paramname">eAction</td><td>Specifies how the notification updates the task's notification value, if at all. Valid values for eAction are as follows:</td></tr>
</table>
</dd>
</dl>
<p>eSetBits - The task's notification value is bitwise ORed with ulValue. xTaskNofify() always returns pdPASS in this case.</p>
<p>eIncrement - The task's notification value is incremented. ulValue is not used and <a class="el" href="task_8h.html#a0d2d54fb8a64011dfbb54983e4ed06bd">xTaskNotify()</a> always returns pdPASS in this case.</p>
<p>eSetValueWithOverwrite - The task's notification value is set to the value of ulValue, even if the task being notified had not yet processed the previous notification (the task already had a notification pending). <a class="el" href="task_8h.html#a0d2d54fb8a64011dfbb54983e4ed06bd">xTaskNotify()</a> always returns pdPASS in this case.</p>
<p>eSetValueWithoutOverwrite - If the task being notified did not already have a notification pending then the task's notification value is set to ulValue and <a class="el" href="task_8h.html#a0d2d54fb8a64011dfbb54983e4ed06bd">xTaskNotify()</a> will return pdPASS. If the task being notified already had a notification pending then no action is performed and pdFAIL is returned.</p>
<p>eNoAction - The task receives a notification without its notification value being updated. ulValue is not used and <a class="el" href="task_8h.html#a0d2d54fb8a64011dfbb54983e4ed06bd">xTaskNotify()</a> always returns pdPASS in this case.</p>
<p>pulPreviousNotificationValue - Can be used to pass out the subject task's notification value before any bits are modified by the notify function.</p>
<dl class="section return"><dt>Returns</dt><dd>Dependent on the value of eAction. See the description of the eAction parameter.</dd></dl>
<p>task. h </p><pre>BaseType_t <a class="el" href="task_8h.html#a1ed9129068b96a909356bd0369c5ecb0">xTaskNotifyFromISR( TaskHandle_t xTaskToNotify, uint32_t ulValue, eNotifyAction eAction, BaseType_t *pxHigherPriorityTaskWoken )</a>;</pre><p>configUSE_TASK_NOTIFICATIONS must be undefined or defined as 1 for this function to be available.</p>
<p>When configUSE_TASK_NOTIFICATIONS is set to one each task has its own private "notification value", which is a 32-bit unsigned integer (uint32_t).</p>
<p>A version of <a class="el" href="task_8h.html#a0d2d54fb8a64011dfbb54983e4ed06bd">xTaskNotify()</a> that can be used from an interrupt service routine (ISR).</p>
<p>Events can be sent to a task using an intermediary object. Examples of such objects are queues, semaphores, mutexes and event groups. Task notifications are a method of sending an event directly to a task without the need for such an intermediary object.</p>
<p>A notification sent to a task can optionally perform an action, such as update, overwrite or increment the task's notification value. In that way task notifications can be used to send data to a task, or be used as light weight and fast binary or counting semaphores.</p>
<p>A notification sent to a task will remain pending until it is cleared by the task calling <a class="el" href="task_8h.html#a0475fcda9718f403521c270a7270ff93">xTaskNotifyWait()</a> or <a class="el" href="task_8h.html#a66540bef602522a01a519f776e4c07d8">ulTaskNotifyTake()</a>. If the task was already in the Blocked state to wait for a notification when the notification arrives then the task will automatically be removed from the Blocked state (unblocked) and the notification cleared.</p>
<p>A task can use <a class="el" href="task_8h.html#a0475fcda9718f403521c270a7270ff93">xTaskNotifyWait()</a> to [optionally] block to wait for a notification to be pending, or <a class="el" href="task_8h.html#a66540bef602522a01a519f776e4c07d8">ulTaskNotifyTake()</a> to [optionally] block to wait for its notification value to have a non-zero value. The task does not consume any CPU time while it is in the Blocked state.</p>
<p>See <a href="http://www.FreeRTOS.org/RTOS-task-notifications.html">http://www.FreeRTOS.org/RTOS-task-notifications.html</a> for details.</p>
<dl class="params"><dt>Parameters</dt><dd>
<table class="params">
<tr><td class="paramname">xTaskToNotify</td><td>The handle of the task being notified. The handle to a task can be returned from the xTaskCreate() API function used to create the task, and the handle of the currently running task can be obtained by calling <a class="el" href="task_8h.html#a85a0f9c9f817b18686efbf8f37c72dfc">xTaskGetCurrentTaskHandle()</a>.</td></tr>
<tr><td class="paramname">ulValue</td><td>Data that can be sent with the notification. How the data is used depends on the value of the eAction parameter.</td></tr>
<tr><td class="paramname">eAction</td><td>Specifies how the notification updates the task's notification value, if at all. Valid values for eAction are as follows:</td></tr>
</table>
</dd>
</dl>
<p>eSetBits - The task's notification value is bitwise ORed with ulValue. xTaskNofify() always returns pdPASS in this case.</p>
<p>eIncrement - The task's notification value is incremented. ulValue is not used and <a class="el" href="task_8h.html#a0d2d54fb8a64011dfbb54983e4ed06bd">xTaskNotify()</a> always returns pdPASS in this case.</p>
<p>eSetValueWithOverwrite - The task's notification value is set to the value of ulValue, even if the task being notified had not yet processed the previous notification (the task already had a notification pending). <a class="el" href="task_8h.html#a0d2d54fb8a64011dfbb54983e4ed06bd">xTaskNotify()</a> always returns pdPASS in this case.</p>
<p>eSetValueWithoutOverwrite - If the task being notified did not already have a notification pending then the task's notification value is set to ulValue and <a class="el" href="task_8h.html#a0d2d54fb8a64011dfbb54983e4ed06bd">xTaskNotify()</a> will return pdPASS. If the task being notified already had a notification pending then no action is performed and pdFAIL is returned.</p>
<p>eNoAction - The task receives a notification without its notification value being updated. ulValue is not used and <a class="el" href="task_8h.html#a0d2d54fb8a64011dfbb54983e4ed06bd">xTaskNotify()</a> always returns pdPASS in this case.</p>
<dl class="params"><dt>Parameters</dt><dd>
<table class="params">
<tr><td class="paramname">pxHigherPriorityTaskWoken</td><td><a class="el" href="task_8h.html#a1ed9129068b96a909356bd0369c5ecb0">xTaskNotifyFromISR()</a> will set *pxHigherPriorityTaskWoken to pdTRUE if sending the notification caused the task to which the notification was sent to leave the Blocked state, and the unblocked task has a priority higher than the currently running task. If <a class="el" href="task_8h.html#a1ed9129068b96a909356bd0369c5ecb0">xTaskNotifyFromISR()</a> sets this value to pdTRUE then a context switch should be requested before the interrupt is exited. How a context switch is requested from an ISR is dependent on the port - see the documentation page for the port in use.</td></tr>
</table>
</dd>
</dl>
<dl class="section return"><dt>Returns</dt><dd>Dependent on the value of eAction. See the description of the eAction parameter. </dd></dl>
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