Example of object definition
============================

The following example shows how a single CAN object can be defined.  The
driver should already having been opened::

  void define_object(int driver_handle)
    { /* it is assumed that the driver has been opened before and
         that <driver_handle> is the handle returned by the 
         open() - command */
      vcan_status_data vstat; /* a variable that is needed for driver-status
                                 commands such as defining a CAN object */
                                 
      printf("defining an read-object on CAN id 123,\n"
             "port 0 with a timeout of 1000 ms\n");
      vstat.tag              = VCAN_OBJECT_MODE;/* a "Object-Mode"-command */
      vstat.data.mode.mode   = VCAN_MODE_READ;  /* the object-mode: READ */
      vstat.data.mode.port   = 0;               /* Port 0 */
      vstat.data.mode.id     = 123;             /* CAN id 123 */
      vstat.data.mode.timeout= 1000;            /* timeout: 1000 ms */
      ioctl(handle, 0, (char *)(&vstat)); 
     
      if (vstat.errcode!=VCAN_NO_ERROR)
        /* an error occured : */
        { printf("ioctl returned the following error: %d ", vstat.errcode);
          /* you could compare the error-code against the symbolic 
             error-names of the type vcan_errcodes and react accordingly */
          printf("fatal error\n");
          return;
        }
      printf("done\n");
    }