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usbd_descriptor()

Get USB descriptors.

Synopsis:

#include <sys/usbdi.h>

int usbd_descriptor( struct usbd_device *device, 
                     int set, _uint8 type, _uint16 rtype, 
                     _uint8 index, _uint16 langid, 
                     _uint8 *desc, size_t len );

Description:

The usbd_descriptor() function lets you obtain the USB descriptors.

device

An opaque handle used to identify the USB device.

set

A flag that says to either get or set a descriptor.

type

Type of descriptor (e.g. USB_DESC_DEVICE, USB_DESC_CONFIGURATION, USB_DESC_STRING, USB_DESC_HUB).

rtype

Type of request (e.g. USB_RECIPIENT_DEVICE, USB_RECIPIENT_INTERFACE, USB_RECIPIENT_ENDPOINT, USB_RECIPIENT_OTHER, USB_TYPE_STANDARD, USB_TYPE_CLASS, USB_TYPE_VENDOR).

index

This varies, depending on the request. It's used for passing a parameter to the device.

langid

Identifies the language supported in strings (according to the LANGID table).

desc

Pointer at buffer to put descriptors.

len

The length of the data transfer in bytes.

Returns:

EMSGSIZE

Buffer too small for descriptor.

ENOMEM

No memory for URB.

ENODEV

Device was removed.

EIO

I/O error on USB device.

Classification:

QNX Neutrino, QNX 4

See also:

usbd_feature() usbd_io(), usbd_setup_bulk(), usbd_setup_control(), usbd_setup_interrupt(), usbd_setup_isochronous(), usbd_setup_vendor(), usbd_status()