How to use taskNotify to replace xEventGroupGetBits()

liangmiao wrote on Tuesday, June 20, 2017:

I’m new to freeRTOS. I’m looking for a taskNotify function that can replace xEventGroupGetBits(), i.e. query the notification without blocking or waiting.

According to freeRTOS documentation (, an RTOS task can use ulTaskNotifyTake() to [optionally] block to wait for a the task’s notification value to be non-zero. So it sounds there is an option not to block, but I’m not quite sure how. I was thinking to set the xTicksToWait to “0”, but apparently the document says it must be a number that is greater than “0”.


rtel wrote on Tuesday, June 20, 2017:

As far as I recall, all blocking API functions can accept a block time
of 0. Please provide a reference to the documentation that says this is
not the case.

liangmiao wrote on Tuesday, June 20, 2017:

Thanks for the prompt reply.

I checked the manual again and can’t find the restriction. I was probably looking at the wrong doc previously, appologize for the confusion. If “0” is the valid value for the wait time, then that’s exact what I wanted. Thanks for the help.