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 language-specific data
    area address.

 unwind_lsda_p

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

    Address of a quadword to receive the address of the language-
    specific data area, if there is one.