# Does kernel only sets pxHigherPriorityTaskWoken to pdTRUE and never resets it?

**URL:** <https://forums.freertos.org/t/does-kernel-only-sets-pxhigherprioritytaskwoken-to-pdtrue-and-never-resets-it/397>\
**Category:** Kernel\
**Created:** [November 26, 2013, 9:59am UTC](https://forums.freertos.org/t/does-kernel-only-sets-pxhigherprioritytaskwoken-to-pdtrue-and-never-resets-it/397 "2013-11-26T09:59:14Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![system](https://d2v6vdsk2p900z.cloudfront.net/original/1X/7fc8fdb729c645aab5b20282bbe34e57cb407be6.jpeg) [@system](https://forums.freertos.org/u/system)\
**Post date:** [November 26, 2013, 9:59am UTC](https://forums.freertos.org/t/does-kernel-only-sets-pxhigherprioritytaskwoken-to-pdtrue-and-never-resets-it/397/1 "2013-11-26T09:59:14Z")

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**[beginend1](https://sourceforge.net/u/beginend1/)** wrote on [Tuesday, November 26, 2013](https://sourceforge.net/p/freertos/discussion/382005/thread/10c64d91/#5163):

Can I safety assume, that is calling any kernel code that takes pxHigherPriorityTaskWoken will only set given variable and never will reset it?

```
...
signed portBASE_TYPE need_yeld = pdFALSE;
xQueueSendToBackFromISR( some_queue, sime_item_ptr, &need_yeld );
xTimerStartFromISR( some_timer, &need_yeld );
portEND_SWITCHING_ISR( need_yeld );
...

```

Is this code safe?

---

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**Author:** ![rtel](https://d3iykfbgfh8zhg.cloudfront.net/user_avatar/forums.freertos.org/rtel/32/31_2.png) [@rtel](https://forums.freertos.org/u/rtel)\
**Post date:** [November 26, 2013, 10:00am UTC](https://forums.freertos.org/t/does-kernel-only-sets-pxhigherprioritytaskwoken-to-pdtrue-and-never-resets-it/397/2 "2013-11-26T10:00:57Z")

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**[rtel](https://sourceforge.net/u/rtel/)** wrote on [Tuesday, November 26, 2013](https://sourceforge.net/p/freertos/discussion/382005/thread/10c64d91/#56dd):

Yes that is safe - in fact you are using it exactly as it is intended to be used.

Regards.