pc_value
    OpenVMS usage:PC value
    type:         quadword
    access:       read
    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 condition handler pointer.
 handler_fv
    OpenVMS usage:address
    type:         quadword
    access:       write
    mechanism:    by reference
    A quadword to receive the function value of the procedure
    descriptor for the condition handler, if there is one.