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UID title description old-location tech.root ms.date keywords ms.keywords req.header req.include-header req.target-type req.target-min-winverclnt req.target-min-winversvr req.kmdf-ver req.umdf-ver req.ddi-compliance req.unicode-ansi req.idl req.max-support req.namespace req.assembly req.type-library req.lib req.dll req.irql targetos req.typenames f1_keywords topic_type api_type api_location api_name
NI:hidclass.IOCTL_GET_NUM_DEVICE_INPUT_BUFFERS
IOCTL_GET_NUM_DEVICE_INPUT_BUFFERS (hidclass.h)
The IOCTL_GET_NUM_DEVICE_INPUT_BUFFERS request obtains the size of the input report queue for a top-level collection.
hid\ioctl_get_num_device_input_buffers.htm
hid
04/30/2018
IOCTL_GET_NUM_DEVICE_INPUT_BUFFERS IOCTL
IOCTL_GET_NUM_DEVICE_INPUT_BUFFERS, IOCTL_GET_NUM_DEVICE_INPUT_BUFFERS control, IOCTL_GET_NUM_DEVICE_INPUT_BUFFERS control code [Human Input Devices], hid.ioctl_get_num_device_input_buffers, hidclass/IOCTL_GET_NUM_DEVICE_INPUT_BUFFERS, hidioreq_4d76e323-5cc1-40d2-aa56-ca5427f15e6f.xml
hidclass.h
Hidclass.h
Windows
Windows
IOCTL_GET_NUM_DEVICE_INPUT_BUFFERS
hidclass/IOCTL_GET_NUM_DEVICE_INPUT_BUFFERS
APIRef
kbSyntax
HeaderDef
hidclass.h
IOCTL_GET_NUM_DEVICE_INPUT_BUFFERS

IOCTL_GET_NUM_DEVICE_INPUT_BUFFERS IOCTL

-description

The IOCTL_GET_NUM_DEVICE_INPUT_BUFFERS request obtains the size of the input report queue for a top-level collection.

The input report queue is implemented as a ring buffer. If a collection transmits data to the HID class driver faster than the input reports are read, reports can be lost. The size of the input report queue can be adjusted using IOCTL_SET_NUM_DEVICE_INPUT_BUFFERS.

For general information about HIDClass devices, see HID Collections.

-ioctlparameters

-ioctl-major-code

-input-buffer

Parameters.DeviceIoControl.OutputBufferLength in the I/O stack location of the IRP indicates the size, in bytes, of the output buffer, which must be >= sizeof(ULONG).

-input-buffer-length

The size of the buffer is sizeof(ULONG).

-output-buffer

Irp->AssociatedIrp.SystemBuffer points to a buffer that will receive the size of the report input queue.

-output-buffer-length

The size of the buffer is sizeof(ULONG).

-in-out-buffer

-inout-buffer-length

-status-block

The HID class driver sets the following fields of Irp->IoStatus:

  • Information is set to sizeof(ULONG) if the size of the report input queue is successfully retrieved.
  • Status is set to STATUS_SUCCESS if the transfer completed without error. Otherwise, it is set to an appropriate NTSTATUS error code.

-see-also

HidD_SetNumInputBuffers