Hi, I am developing a MMORPG.. OK... I rambled ! to put this short : I want to be prompted after x amount of time that say for example that a NPC needs to do something new any ideas ?? .. the long explanation below of what i have done (basically) I came up with the following for when an NPC needs to do something : Note - its a kind of realtime/turn based game - by this i meen.. for example a NPC moves 3 squares and then has to wait x time before they can do something else. I needed to have some way of assigning new tasks to NPCs who are ready to do something.. I could have looped through every NPC checking if they are inactive and then assign a task.. but this could waste a lot of time if there are 1000s of NPC so I made a component which basically did the following : contained a circular array of linked lists. each ellement of the list represents a set period (say 250 ms) and each ellement can hold a pointer to an "event" which can in turn point to another "event" and so on (so 2 events can occure on the same 250ms period) By using this structure and a timer i managed to produce something that would call a event after a set period (rounded up to the nearest time slot) returning the data i passed in (ie the NPC id) so i would know that NPC would need processing the problem i have narrowed down to the fact that sometimes during the event more items are added to the list which causes a problem if it adds to the same ellement which is been processed (ie if there are 10 ellements and time gape of 1000MS if i add an event at 10 seconds from now it will be added to the current ellement in the circular array. Any advice would be great Thanks Tim

Idea #1: Remove the element from the list just before you process it. That way, you''re never going to attach new elements to it.

Idea #2: I don''t see why adding extra elements while processing one will cause a problem unless your circular linked-list structure is not totally reliable. Consider using an array of pointers or even better, an STL container if you are using C++.