pc_value

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

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

 unwind_lsda_p

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

    Address of a location that contains the PC value. pc_value
    is used to find the unwind information block and the unwind
    information block language-specific data area address.