The global functions are used when a large stack space is required. So far, only the waypoint driver's A* algorithm requires this. Initially, this was to be used also for the image and map tranfer functions; but the image tranfer uses the image buffer itsself and the receive task on the host declares its own stack space. The Map tranfer functions similarly update the map incrementally without requiring an intermediate buffer. As I'm imagining any serious image processing would best be left for the host it might not be required. If no serious application beyond A* is find, this variable will probably be eliminated.
The following are the global functions: