Re: [Enigma-devel] Questions about enigma.GetPos()

[Ronald Lamprecht]

Hi,

Markus Laire wrote:
> If I use enigma.GetPos() on an item which is currently in inventory or
> in some bag, it seems to return the position where the item has last
> been on ground.
> If this behaviour likely to remain the same?

No. We are aware of this feature but it will change in future. Thus any 
usage of this feature is depreceated.

> Also, I just noticed that using first
>    dynamite = set_item("it-dynamite", orig_x, orig_y)
> and then later
>    local x, y = enigma.GetPos(dynamite)
> will cause segmentation fault if the dynamite has been exploded.

This is Berlios bug report #8249 "Enigma Lua functions can segfault":

All Enigma Lua functions like SendMessage,... that take an object 
reference as argument can segfault if the object has been deleted (killed).

> Is there a way to check whether the dynamite is still in game without
> giving it a unique name and using "if enigma.GetNamedObject() == nil"

This is currently the only possible workaround at the moment as you need 
a second reference besides the volatile object id.

For 1.00 and 1.01 we fixed dozens of crash situations within the C++ 
engine due to timers and callbacks sending messages to killed objects.

As the current object id used within Lua is additionally a major 
obstacle in saving and restoring a level game at arbitrary points of 
time we decided to reengineer Enigma and to introduce a memory address 
independent object id with a proper management. The reengineering will 
be transparent for Lua levels (besides the vanishing crashes).

Ronald