1. In an asynchronous multiprocessing environment, said environment having memory means for storing indicia of processes, and computing means for accessing said indicia and for executing processes represented by the accessed indicia, said processes communicating only by reading and writing of shared variables, invocation of one process by another using attendant information being denominated as a "call", a multiprocessing environment implemented method for managing a source process invoking a computation to be performed by an external process, said method also managing bidirectional conversion of arguments and result data into forms acceptable to both the source and external processes, comprising the steps of: (a) establishing a message interface between the source and external processes including designating and locally recording argument data types expected by the external process; (b) converting arguments to the data types expected by the external process and converting all calls by a value type from the source process into calls by a pointer type, and passing said converted calls via the interface to the external process; and (c) responsive to completion of external processing, converting result data into data types acceptable to the source process.