VMS Help TCPIP Services, Programming Interfaces, RPC Client Routines, callrpc, Arguments  *Conan The Librarian (sorry for the slow response - running on an old VAX)

 host
    A pointer to the name of the host on which the remote procedure
    resides.
 prognum
    The program number associated with the remote procedure.
 versnum
    The version number associated with the remote procedure.
 procnum
    The procedure number associated with the remote procedure.
 inproc
    The XDR routine used to encode the remote procedure's arguments.
 in
    A pointer to the remote procedure's arguments.
 outproc
    The XDR routine used to decode the remote procedure's results.
 out
    A pointer to the remote procedure's results.