ZDoom

Ah, ok. I was looking for a function that is called when a player does InvDrop on an artifact in the inventory bar. So this is not that. I've been told I can override CreateTossable() to get what I'm looking for.

Oh, it does get called, just look for A_DropItem.

What are you trying to do? From a look at the code all this function seems to be doing is to run a special action instead of dropping the item if it is being used as an enemy drop on death.
Looking deeper, this is to support some Strife hacks that let enemies drop some special 'action' items from a conversation script that trigger map actions, like opening a door or raising the alarm, etc.

From the code comments I thought this function is called before a drop and can abort the drop with it's return, but it never gets called.
I asked about it in scripting and was told to report it.
Original thread with example