(I64 only.) The Get Previous Invocation Handle routine gets an
    invocation handle of the procedure context preceding that of a
    specified procedure context.

    Format

      LIB$I64_GET_PREV_INVO_HANDLE  invo_handle_in, invo_handle_out

1 - Returns

    OpenVMS usage:cond_value
    type:         longword (unsigned)
    access:       write only
    mechanism:    by value

2 - Argument

 invo_handle_in

    OpenVMS usage:invo_handle
    type:         quadword
    access:       read only
    mechanism:    by reference

    The address of an invocation handle that represents a target
    invocation context.

 invo_handle_out

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

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