Modifies the characteristics of a device or the paths used to
    access that device.

    The $SET_DEVICEW completes synchronously; that is, it returns to
    the caller only after the requested action has taken effect.

    Format

      SYS$SET_DEVICEW  [efn] [,chan] [,devnam] ,itmlst [,iosb]

                       [,astadr] [,astprm] [,nullarg]

    C Prototype

      int sys$set_devicew  (unsigned int efn, unsigned short

                           int chan, void *devnam, void

                           *itmlst, struct _iosb *iosb, void

                           (*astadr)(__unknown_params), int astprm,

                           struct_generic_64 *nullarg);