when a program quits. the new operating systems like win2k and winxp ( using nt based tech) should be able to clear all memmory allocated. while the software thinkgs it has such and such adressable memmory, this is all maintained by the OS and typically it should be cleaned out well. if you were using c++ i'd recommend to lookout for "temp objects" created with an implicit constructor call that don't really act as temp objects and are left occupying memmory.
one soultion used by others to track memmory bugs is to overload the new and delete or in your case perhaps malloc() and free() such that they print to a log of all allocations and deallocations, as well since it's a debuggin tool, to keep a list of allocated items in memmory and then output the list to the log at program termination.