HidD_GetInputReport function

Description

The HidD_GetInputReport routine returns an input report from a top-level collection.

Only use this routine to obtain the current state of a collection. If an application attempts to use this routine to continuously obtain input reports, the reports can be lost. For more information, see Obtaining HID Reports by user-mode applications.

Parameters

HidDeviceObject [in]

An open handle to a top-level collection.

ReportBuffer [out]

Pointer to a caller-allocated input report buffer that the caller uses to specify a HID report ID and HidD_GetInputReport uses to return the specified input report.

For more information about this parameter, see the Remarks section.

ReportBufferLength [in]

The size of the report buffer in bytes. The report buffer must be large enough to hold the input report plus one additional byte that specifies a report ID. If report ID is not used, the ID value is zero.

Return value

HidD_GetInputReport returns TRUE if it succeeds; otherwise, it returns FALSE. Use GetLastError to get extended error information.

Remarks

The correct _ReportBufferLength_ is specified by the _InputReportByteLength_ member of a top-level collection's HIDP_CAPS structure returned from HidP_GetCaps call.

Before it calls the HidD_GetInputReport routine, the caller must do the following:

• If the top-level collection includes report IDs, the caller must set the first byte of the ReportBuffer parameter to a nonzero report ID.
• If the top-level collection does not include report IDs, the caller must set the first byte of the ReportBuffer parameter to zero.

The input report is returned in the ReportBuffer parameter. Depending on the report ID, the caller parses the report by calling one of the following functions:

• HidP_GetButtonCaps
• HidP_GetData
• HidP_GetExtendedAttributes
• HidP_GetScaledUsageValue
• HidP_GetSpecificButtonCaps
• HidP_GetSpecificValueCaps
• HidP_GetUsages
• HidP_GetUsagesEx
• HidP_GetUsageValue
• HidP_GetUsageValueArray
• HidP_GetValueCaps

For an example of how to parse a HID report, see the HClient sample application.

Only user-mode applications can call HidD_GetInputReport. Kernel-mode drivers can use an IOCTL_HID_GET_INPUT_REPORTrequest.

For more information, see Interpreting HID Reports.

See also

• HidD_GetFeature
• HidD_SetFeature
• HidD_SetOutputReport
• HIDP_CAPS
• HidP_GetCaps
• IOCTL_HID_GET_FEATURE
• IOCTL_HID_GET_INPUT_REPORT
• IOCTL_HID_SET_FEATURE
• IOCTL_HID_SET_OUTPUT_REPORT