CopyStringDescriptor
Returns a descriptor from the device in the specified language.
Declaration
virtual const IOUSBStringDescriptor * CopyStringDescriptor(uint8_t index, uint16_t languageID);Parameters
- index:
The descriptor’s index value.
- languageID:
The descriptor’s language ID. You can get the current list of valid language IDs at Www.usb.
Return Value
A pointer to the descriptor, or NULL if the descriptor isn’t found. It’s your responsibility to free the returned descriptor.
Discussion
This method uses a GET_DESCRIPTOR control request (USB 2.0, section 9.4.3) to fetch the string descriptor from the device. The method puts the index value in the low byte of the wValue field, and puts the languageID value in the wIndex field of the request structure.