# What is the purpose of portEND\_SWITCHING\_ISR?

**URL:** <https://forums.freertos.org/t/what-is-the-purpose-of-portend-switching-isr/3360>\
**Category:** Kernel\
**Created:** [November 5, 2012, 5:48pm UTC](https://forums.freertos.org/t/what-is-the-purpose-of-portend-switching-isr/3360 "2012-11-05T17:48:23Z")\
**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 5, 2012, 5:48pm UTC](https://forums.freertos.org/t/what-is-the-purpose-of-portend-switching-isr/3360/1 "2012-11-05T17:48:23Z")

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**[jorsborn](https://sourceforge.net/u/jorsborn/)** wrote on [Monday, November 05, 2012](https://sourceforge.net/p/freertos/discussion/382005/thread/958c7f77/#9bbf):

I am trying to figure out the purpose of the following bit of code in the LM3S811 example:

portEND\_SWITCHING\_ISR( xHigherPriorityTaskWoken );

It occurs right after giving the semaphore. I expected to find this documentation under the ‘FreeRTOS MPU Specific’ area but&nbsp; no joy. I have omitted it in my application and all seems well… not that this means a whole lot.

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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 5, 2012, 7:19pm UTC](https://forums.freertos.org/t/what-is-the-purpose-of-portend-switching-isr/3360/2 "2012-11-05T19:19:59Z")

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**[rtel](https://sourceforge.net/u/rtel/)** wrote on [Monday, November 05, 2012](https://sourceforge.net/p/freertos/discussion/382005/thread/958c7f77/#9f4c):

Note that is a really, really, really old demo, and does not demonstrate many of the new features.

The macro is mentioned in the Interrupt Service Routines section on the documentation page for the demo (which is also really old). [http://www.freertos.org/portlm3s811keil.html](http://www.freertos.org/portlm3s811keil.html)

The API documentation pages for the ISR safe API also gives some information, although note the comment that the macro names are not always consistent between ports:

An example [http://www.freertos.org/a00119.html](http://www.freertos.org/a00119.html)

Regards.