ip_value

    OpenVMS usage: IP value
    type:          quadword
    access:        read
    mechanism:     by reference

    Address of a location that contains the IP value. ip_value is
    used to find the unwind information and the unwind condition
    handler pointer.

 handler_pv

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

    A quadword to receive the procedure value for the condition
    handler, if there is one.