Lucent Technologies USS-720 - Manual (Page 78)

7-20 Lucent Technologies Inc.
USS-720 Preliminary User Guide, Rev. 2
USB Device Driver February 1999
13
4 I/O Control Codes (continued)
4.11 IOCTL_GET_CONFIGURATION_DESCRIPTOR
IOCTL_GET_CONFIGURATION_DESCRIPTOR retrieves the current configuration descriptor. Details regarding
parameters and error codes follow.
4.11.1 Parameters
lpInBuffer—Points to an input buffer. Not used with this operation. Set to NULL.
nInBufferSize—Specifies the size (in bytes) of the buffer pointed to by lpInBuffer. Not used with this operation. Set
to zero.
lpOutBuffer—Points to an output buffer that will receive a USB_CONFIGURATION_DESCRIPTOR data structure
(see
WDM USB Driver Specification).
nOutBufferSize—Specifies the size (in bytes) of the buffer pointed to by lpOutBuffer, which must be large enough to
contain the USB_CONFIGURATION_DESCRIPTOR data structure (see
WDM USB Driver Specification). Specify
zero to return only the length of the Device ID string in lpBytesReturned.
lpBytesReturned—Points to a DWORD that receives the actual size (in bytes) of the data stored into lpOutBuffer.
4.11.2 Notes
None.
4.11.3 Error Code
ERROR_NOT_ENOUGH_BUFFER—lpOutBuffer was not large enough to receive the USB Configuration
Descriptor.