本人小白，使用libusb时，libusb_bulk_transfer返回一直是-5，即/** Entity not found */

[sinat_26315741]

endpoint_num = bEndpointAddress & 0x07;
state = libusb_set_configuration(handle, bConfigurationValue);
std::cout << state << std::endl;
state = libusb_claim_interface(handle, 0);
std::cout << state << std::endl;
unsigned char data[1024] = {0};
int length = 0;
while (length == 0)
int s = libusb_bulk_transfer(handle, endpoint_num, data, wMaxPacketSize, &length, 50000);
std::cout << data << std::endl;

除了这个函数外，其他函数都是返回成功的。