Out of the Heap an Exchange will be created. If szBlockSize is 0 at the call, a NormalExchange will be created. If at the call the number of desired messages is passed in ctNumMsg, and the required message size in szBlockSize, a ResourceExchange will be created. The corresponding number of message objects will be generated. Then with theses message objects the ResourceExchange object will be initialized. If no callback should be done, the value CB.gc_cbNULL must be passed for eSendMsg, eReceiveMsg or eXchgEmpty. Via ctMumPrios the number of possible priorities can be specified.