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");
  }