IWDFIoRequest2::GetRequestorMode method

[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 GetRequestorMode method indicates whether an I/O request came from a kernel-mode driver or a user-mode component (either an application or a user-mode driver).

Syntax


WDF_KPROCESSOR_MODE GetRequestorMode();

Parameters

This method has no parameters.

Return value

GetRequestorMode returns a WDF_KPROCESSOR_MODE-typed value that indicates whether the current I/O request came from a kernel-mode driver or a user-mode component.

Remarks

A UMDF-based driver can receive an I/O request from a kernel-mode driver only if the UMDF-based driver supports kernel-mode clients.

If GetRequestorMode returns WdfUserMode, the driver can call IWDFIoRequest2::IsFromUserModeDriver to determine if the I/O request came from an application or a user-mode driver.

Examples

The following code example shows how an IQueueCallbackWrite::OnWrite callback function can determine whether an I/O request is from kernel mode or user mode. If the request is from user mode, the example determines whether the request is from an application or another user-mode driver.


VOID
STDMETHODCALLTYPE
  CMyQueue::OnWrite(
    __in IWDFIoQueue *pWdfQueue,
    __in IWDFIoRequest *pWdfRequest,
    __in SIZE_T BytesToWrite
    )
{
 WDF_KPROCESSOR_MODE processorMode;
    BOOL fromApp = FALSE;
    //
    // Declare an IWDFIoRequest2 interface pointer and obtain the
    // IWDFIoRequest2 interface from the IWDFIoRequest interface.
    //
    CComQIPtr<IWDFIoRequest2> r2 = pWdfRequest;

    processorMode = r2->GetRequestorMode();
    if (processorMode == WdfUserMode)
    {
        fromApp = r2->IsFromUserModeDriver();
    }
...
}

Requirements

Target platform

Desktop

End of support

Unavailable in UMDF 2.0 and later.

Minimum UMDF version

1.9

Header

Wudfddi.h (include Wudfddi.h)

DLL

WUDFx.dll

See also

IWDFIoRequest2
IWDFIoRequest2::IsFromUserModeDriver

 

 

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