invo_context

    OpenVMS usage: invo_context_blk
    type:          structure
    access:        read
    mechanism:     by reference

    Address of a valid invocation context block.

 invo_handle

    OpenVMS usage: invo_handle
    type:          quadword
    access:        write
    mechanism:     by reference

    Address of the location into which the invocation context
    handle is to be written. If the call fails, the value of the
    invocation context handle is LIB$K_INVO_HANDLE_NULL.