Lucent Technologies USS-720 Ioctlgetportstatus, 4 I/O Control Codes continued, USB Device Driver

USS-720	Preliminary User Guide, Rev. 2
USB Device Driver	February 1999

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-720USB-to-IEEE 1284 Bridge Preliminary Data Sheet, “Get_Port_Status”):

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.

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.

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