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usbd_interface_descriptor()

Get the interface descriptor for a specific interface setting

Synopsis:

#include <sys/usbdi.h>

usbd_interface_descriptor_t 
   *usbd_interface_descriptor(
       struct usbd_device *device,                          
       _uint8 cfg,                                          
       _uint8 ifc,                                          
       _uint8 alt,                                          
       struct usbd_desc_node **node );                       

Description:

The usbd_interface_descriptor() function lets you obtain the interface descriptor for a specific interface setting.

device

An opaque handle used to identify the USB device.

cfg

The device's configuration identifier (bConfigurationValue).

ifc

Interface identifier (bInterfaceNumber).

alt

Alternate identifier (bAlternateSetting).

node

Indicates the descriptor's location for rooting future requests (e.g. endpoints of this interface).

The usbd_interface_descriptor_t structure looks like this:

typedef struct usbd_interface_descriptor {
    _uint8                  bLength;
    _uint8                  bDescriptorType;
    _uint8                  bInterfaceNumber;
    _uint8                  bAlternateSetting;
    _uint8                  bNumEndpoints;
    _uint8                  bInterfaceClass;
    _uint8                  bInterfaceSubClass;
    _uint8                  bInterfaceProtocol;
    _uint8                  iInterface;
} usbd_interface_descriptor_t;

Returns:

A pointer to usbd_interface_descriptor_t on success, 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_languages_descriptor(), usbd_parse_descriptors(), usbd_string(), usbd_urb_status()