# xSemaphoreGiveFromISR second argument

**URL:** <https://forums.freertos.org/t/xsemaphoregivefromisr-second-argument/3308>\
**Category:** Kernel\
**Created:** [April 10, 2012, 6:51am UTC](https://forums.freertos.org/t/xsemaphoregivefromisr-second-argument/3308 "2012-04-10T06:51:16Z")\
**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:** [April 10, 2012, 6:51am UTC](https://forums.freertos.org/t/xsemaphoregivefromisr-second-argument/3308/1 "2012-04-10T06:51:16Z")

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**[pbleyer](https://sourceforge.net/u/pbleyer/)** wrote on [Tuesday, April 10, 2012](https://sourceforge.net/p/freertos/discussion/382005/thread/9167188c/#52bf):

Hello.

Is there a reason NULL is not allowed as the pxHigherPriorityTaskWoken argument of xSemaphoreGiveFromISR? Many times I don’t need to know if a higher priority task was awaken and could pass NULL to the function instead, like some other API functions.

Thanks. Regards.

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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:** [April 10, 2012, 8:44am UTC](https://forums.freertos.org/t/xsemaphoregivefromisr-second-argument/3308/2 "2012-04-10T08:44:29Z")

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**[rtel](https://sourceforge.net/u/rtel/)** wrote on [Tuesday, April 10, 2012](https://sourceforge.net/p/freertos/discussion/382005/thread/9167188c/#7d70):

No particular reason over and above keeping the code size and run time to a minimum.&nbsp; Feel free to add it to the feature request tracker and it will get added in at some point.

Regards.