Given an ip_value, find the procedure value for the condition
    handler, if present, and write it to handler_pv. If not
    present, then write 0 to handler_pv.

    Format
      LIB$X86_GET_UNWIND_HANDLER_PV (ip_value, handler_pv)

1  –  Returns

 status

    A value of 1 indicates success. A value of 0 indicates failure.

2  –  Arguments

 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.