IOCTL_GENERICUSBFN_GET_INTERFACE_DESCRIPTOR_SET IOCTL (genericusbfnioctl.h)

Article
10/21/2021

This I/O control code (IOCTL) is sent by a user-mode service or application to get the entire Universal Serial Bus (USB) interface descriptor set for a function on the device.

Note This IOCTL request does not retrieve the interface descriptor set for the entire device.

Input buffer

A pointer to a USBFN_INTERFACE_INFO structure.

Input buffer length

The size of a USBFN_INTERFACE_INFO structure.

Output buffer

A pointer to a buffer that contains a USBFN_INTERFACE_INFO structure. The USB function class extension (UFX) populates the structure with the entire interface descriptor set including its endpoint descriptors.

Output buffer length

The size of a USBFN_INTERFACE_INFO.

Remarks

This request must be sent after sending the IOCTL_GENERICUSBFN_ACTIVATE_USB_BUS request.

The length of the entire interface descriptor is variable. The class driver might need to send this IOCTL request twice to get the entire descriptor set.

If the length of the entire descriptor set is greater than the specified output buffer length, UFX sets the Size member of USBFN_INTERFACE_INFO to the actual buffer length and fails the request with STATUS_BUFFER_TOO_SMALL. The driver must then allocated an output buffer of length specified by Size and resend the request.

If this I/O control code (IOCTL) is being called synchronously, set the lpOverlapped parameter to NULL. If this IOCTL is called asynchronously, assign the lpOverlapped parameter to a pointer to an OVERLAPPED structure that contains a handle to an event object. The event objects signal when the operation is completed.

The return value is a BOOL value that indicates success or failure of the operation. TRUE indicates success, FALSE otherwise.

Requirements

Requirement	Value
Header	genericusbfnioctl.h (include GenericUsbFnIoctl.h)

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