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usbd_string()

Get a string descriptor

Synopsis:

#include <sys/usbdi.h>

char *usbd_string( struct usbd_device *device, 
                   _uint8 index, 
                   int langid );

Description:

The usbd_string() function lets you obtain a string from the USB device's table of strings.

Typically, the string table may contain the names of the vendor, the product, etc. The string table is optional.

device

An opaque handle used to identify the USB device.

index

Index into the device's (optional) string table.

langid

Language ID. The usbd_languages_descriptor() function provides the supported langids for the device. If you specify 0, the usbd_string() function will select the first/only supported language.

Note that the strings are actually in Unicode/wide characters, so usb_string() also conveniently converts them to UTF-8 (byte stream) for you.

Note that usbd_string() places the result string in a static buffer that's reused every time the function is called.

Returns:

A pointer to the string in an internal static buffer, or NULL on error.

Classification:

QNX Neutrino, QNX 4

See also:

usbd_args_lookup(), usbd_configuration_descriptor(), usbd_device_lookup(), usbd_device_extra(), usbd_device_descriptor(), usbd_endpoint_descriptor(), usbd_hcd_info(), usbd_hub_descriptor(), usbd_interface_descriptor(), usbd_languages_descriptor(), usbd_parse_descriptors(), usbd_urb_status()