Lucent Technologies USS-720 - Manual (Page 76)

7-18 Lucent Technologies Inc.
USS-720 Preliminary User Guide, Rev. 2
USB Device Driver February 1999
13
4 I/O Control Codes (continued)
4.9 IOCTL_GET_ALTSETTING
IOCTL_GET_ALTSETTING retrieves the current alternate interface setting from the USS-720 device. Details
regarding parameters and error codes follow.
4.9.1 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 single byte indicating the current alternate setting based
on one of the following:
nOutBufferSize—Specifies the size (in bytes) of the buffer pointed to by lpOutBuffer. The buffer must be large
enough to contain one byte value.
lpBytesReturned—Points to a DWORD that receives the actual size (in bytes) of the data stored into lpOutBuffer.
4.9.2 Notes
None.
4.9.3 Error Code
ERROR_NOT_ENOUGH_BUFFER—lpOutBuffer needs to be large enough to contain one byte value.
Value Description
ALT_INTERFACE_0 Bulk Out pipe only.
ALT_INTERFACE_1 Bulk Out and Bulk In pipe.
ALT_INTERFACE_2 Bulk Out, Bulk In, Interrupt pipe, and 1284 register capabilities.