usbd_string()

Get a string descriptor

Synopsis:

#include <sys/usbdi.h>

char *usbd_string( struct usbd_device *device, 
                   uint8_t index, 
                   int langid );

Arguments:

device

An opaque handle used to identify the USB device.

index

An index into the device's (optional) string table.

langid

The language ID. The usbd_languages_descriptor() function provides the supported language IDs for the device. If you specify 0, usbd_string() selects the first or only supported language.

Library:

libusbdi

Description:

The usbd_string() function lets you obtain a string from the USB device's table of strings, which typically contains the names of the vendor, the product, etc. The string table is optional.

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The strings are actually in Unicode/wide characters, so usb_string() converts them to UTF-8 (byte stream) for you and places the resulting string in a static buffer that's reused every time the function is called. The returned string includes a terminating null character.

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Returns:

A pointer to the string in an internal static buffer, or NULL on error or if the string table doesn't exist.

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()