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7-24 Lucent Technologies Inc.
USS-720 Preliminary User Guide, Rev. 2
USB Device Driver February 1999
13
4 I/O Control Codes (continued)
4.15 IOCTL_GET_PORT_STATUS
IOCTL_GET_PORT_STATUS returns a status byte. Details regarding parameters and error codes follow.
4.15.1 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 receives a byte indicating the current port status. The bit mask is
defined as follows (see the
USS-720 USB-to-
IEEE
1284 Bridge
Preliminary Data Sheet, “Get_Port_Status”):
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.
4.15.2 Notes
None.
4.15.3 Error Codes
ERROR_INVALID_ALTERNATESETTING—The command is only supported in ALT_INTERFACE_0 and
ALT_INTERFACE_1 (see Section 4.9 of this document).
ERROR_NOT_ENOUGH_BUFFER—lpOutBuffer needs to be large enough to receive the interface information.
STATUS_INSUFFICIENT_RESOURCES—Not enough memory to perform the request on this device instance.
Bit Meaning
0—2 Reserved, will always read 0.
3 0 = error, 1 = no error.
4 Select.
5 Paper empty.
6—7 Reserved, will always read 0.