my_device
static my_device *gDeviceList = NULL;
my_free_device(my_device *device)
my_device *device = (my_device *)cookie;
my_transfer_data(my_device *device, bool directionIn, void *data,
my_modeswitch(my_device* device)
my_device *device = (my_device *)malloc(sizeof(my_device));
my_device *device = (my_device *)cookie;
my_device *element = gDeviceList;