usb_string — returns ISO 8859-1 version of a string descriptor
int usb_string (struct usb_device * dev, int index, char * buf, size_t size);
devthe device whose string descriptor is being retrieved
indexthe number of the descriptor
bufwhere to put the string
sizehow big is “buf”?
This converts the UTF-16LE encoded strings returned by devices, from
usb_get_string_descriptor, to null-terminated ISO-8859-1 encoded ones
that are more usable in most kernel contexts. Note that all characters
in the chosen descriptor that can't be encoded using ISO-8859-1
are converted to the question mark (“?”) character, and this function
chooses strings in the first language supported by the device.
The ASCII (or, redundantly, “US-ASCII”) character set is the seven-bit subset of ISO 8859-1. ISO-8859-1 is the eight-bit subset of Unicode, and is appropriate for use many uses of English and several other Western European languages. (But it doesn't include the “Euro” symbol.)
This call is synchronous, and may not be used in an interrupt context.
Returns length of the string (>= 0) or usb_control_msg status (< 0).