Retrieve a descriptor from a device.
This is a convenience function which formulates the appropriate control
message to retrieve the descriptor. The string returned is Unicode, as
detailed in the USB specifications.
\param dev a device handle
\param desc_index the index of the descriptor to retrieve
\param langid the language ID for the string descriptor
\param data output buffer for descriptor
\param length size of data buffer
\returns number of bytes returned in data, or LIBUSB_ERROR code on failure
\see libusb_get_string_descriptor_ascii()
Retrieve a descriptor from a device. This is a convenience function which formulates the appropriate control message to retrieve the descriptor. The string returned is Unicode, as detailed in the USB specifications.
\param dev a device handle \param desc_index the index of the descriptor to retrieve \param langid the language ID for the string descriptor \param data output buffer for descriptor \param length size of data buffer \returns number of bytes returned in data, or LIBUSB_ERROR code on failure \see libusb_get_string_descriptor_ascii()