Lucent Technologies USS-720 Ioctlgetdeviceinstances, 4 I/O Control Codes continued, February

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

4 I/O Control Codes (continued)

4.13 IOCTL_GET_DEVICE_INSTANCES

IOCTL_GET_DEVICE_INSTANCES returns a list of current devices based on the symbolic links created during each device enumeration. Details regarding parameters and error codes follow.

4.13.1 Parameters

lpInBuffer—Points to an input buffer that will receive. 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 DEVICE_INSTANCE_HEADER structure (see Section 5.1) and a series of DEVICE_INSTANCE structures (see Section 5.2), one for each device instance.

nOutBufferSize—Specifies the size (in bytes) of the buffer pointed to by lpOutBuffer. 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.

4.13.2 Notes

None.

4.13.3 Error Code

ERROR_NOT_ENOUGH_BUFFER—lpOutBuffer needs to be large enough to receive the device instances.

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