How to know what is the return type of the func lv_event_get_param() in a event callback

How-to
1

In the clicked event callback func I notice the return pointer of the lv_event_get_param() is not NULL.But how can i know what is the exactly type of the return pointer.
By the way,II originally wanted to get the coordinate of a table widget when clicked.

2

The type returned by lv_event_get_param() depends on the event and widget.

It’s not always documented, but you can check the source for lv_obj_send_event(). The third parameter is what lv_event_get_param() returns