nf-wudfddi-iwdfiorequest2-getqueryinformationparameters.md

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
NF:wudfddi.IWDFIoRequest2.GetQueryInformationParameters	IWDFIoRequest2::GetQueryInformationParameters (wudfddi.h)	The GetQueryInformationParameters method retrieves parameters that are associated with a WdfRequestQueryInformation-typed I/O request.	wdf\iwdfiorequest2_getqueryinformationparameters.htm	wdf	02/26/2018	IWDFIoRequest2::GetQueryInformationParameters	GetQueryInformationParameters, GetQueryInformationParameters method, GetQueryInformationParameters method,IWDFIoRequest2 interface, IWDFIoRequest2 interface,GetQueryInformationParameters method, IWDFIoRequest2.GetQueryInformationParameters, IWDFIoRequest2::GetQueryInformationParameters, UMDFRequestObjectRef_595d2b4c-1286-4243-b440-0efaae03980d.xml, umdf.iwdfiorequest2_getqueryinformationparameters, wdf.iwdfiorequest2_getqueryinformationparameters, wudfddi/IWDFIoRequest2::GetQueryInformationParameters	wudfddi.h	Wudfddi.h	Desktop				1.9				Unavailable in UMDF 2.0 and later.					WUDFx.dll		Windows		IWDFIoRequest2::GetQueryInformationParameters wudfddi/IWDFIoRequest2::GetQueryInformationParameters	APIRef kbSyntax	COM	WUDFx.dll	IWDFIoRequest2::GetQueryInformationParameters

IWDFIoRequest2::GetQueryInformationParameters

-description

[Warning: UMDF 2 is the latest version of UMDF and supersedes UMDF 1. All new UMDF drivers should be written using UMDF 2. No new features are being added to UMDF 1 and there is limited support for UMDF 1 on newer versions of Windows 10. Universal Windows drivers must use UMDF 2. For more info, see Getting Started with UMDF.]

The GetQueryInformationParameters method retrieves parameters that are associated with a WdfRequestQueryInformation-typed I/O request.

-parameters

-param pInformationClass [out, optional]

A pointer to a driver-allocated variable that receives a WDF_FILE_INFORMATION_CLASS-typed value. This pointer is optional and can be NULL.

-param pSizeInBytes [out, optional]

A pointer to a driver-allocated variable that receives the size, in bytes, of the file information. This pointer is optional and can be NULL.

-remarks

Your driver can call GetQueryInformationParameters to obtain the parameters that are associated with an I/O request, if the request type is WdfRequestQueryInformation. The pInformationClass parameter identifies the type of file information that the driver should provide, and the pSizeInBytes parameter specifies the size of the buffer that will receive the information. The driver can call IWDFIoRequest2::RetrieveOutputBuffer to obtain the buffer address.

Your driver must verify that the specified buffer size is large enough to receive the requested file information.

Examples

The following code example is part of an IQueueCallbackDefaultIoHandler::OnDefaultIoHandler callback function. If the callback function receives a query information request, it retrieves the request's parameters. If the driver supports the specified type of information, it copies the information into the request's output buffer.

void
CMyQueue::OnDefaultIoHandler(
    IWDFIoQueue*  pQueue,
    IWDFIoRequest*  pRequest
    )
{
    HRESULT hr;
    WDF_FILE_INFORMATION_CLASS infoClass;
    SIZE_T bufSize;
    PFILE_BASIC_INFORMATION buffer;

 if (WdfRequestQueryInformation==pRequest->GetType())
    {
        //
        // Declare an IWDFIoRequest2 interface pointer and obtain the
        // IWDFIoRequest2 interface from the IWDFIoRequest interface.
        //
        CComQIPtr<IWDFIoRequest2> r2 = pRequest;
        // 
        // Get the I/O request's parameters.
        // 
        r2->GetQueryInformationParameters(&infoClass,
                                          &bufSize);
        // 
        // This driver supports only FileBasicInformation.
        // 
        if (infoClass != FileBasicInformation)
        {
            hr = HRESULT_FROM_NT(STATUS_NOT_SUPPORTED);
            goto exit;
        }
        // 
        // Validate buffer size.
        // 
        if (bufferCb != sizeof(FILE_BASIC_INFORMATION))
        {
            hr = HRESULT_FROM_NT(STATUS_BUFFER_TOO_SMALL);
            goto exit;
        }
        // 
        // Get output buffer.
        // 
        hr = r2->RetrieveOutputBuffer(sizeof(FILE_BASIC_INFORMATION), 
                                      (PVOID*) &buffer,
                                      &bufferCb);
        if (SUCCEEDED(hr))
        {
            // 
            // Copy file information to output buffer.
            // 
            CopyMemory(buffer,
                       &g_FileInfo,
                       sizeof(FILE_BASIC_INFORMATION));
            r2->SetInformation(sizeof(FILE_BASIC_INFORMATION));
        }
 ...
    }
...
exit:
...
}

-see-also

IWDFIoRequest2

IWDFIoRequest2::GetSetInformationParameters