The ObjectFromTag() function is used to implement COM callback interfaces, pointers and objects. This is documentation for using the function.
When talking about ObjectFromTag(), you cannot get around ObjCreateInterface(). ObjCreateInterface() was introduced in AutoIt version 3.3.8.0 (2011-12-23). The function is coded in the C/C++ language by trancexx.
At the top of the official documentation there is a large warning box. A few comments on this warning:
"This feature is experimen