xTimerCreate: is a NULL callback function pointer valid?

Hi, new to the forum. Can the timer callback function pointer in xTimerCreate be NULL?. I simply want to check if a timer is running, no further actions required.

xTimerCreate: is a NULL callback function pointer valid?

No, the callback cannot be NULL. (The easiest thing to do is look into the source files, which is what I just did. It only took a few seconds to look at the xTimerCreate() function to get the answer).