IWDFDevice::RetrieveDeviceName method (wudfddi.h)

Article
02/22/2024

[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 RetrieveDeviceName method retrieves the name of an underlying kernel-mode device.

Syntax

HRESULT RetrieveDeviceName(
  [out]     PWSTR pDeviceName,
  [in, out] DWORD *pdwDeviceNameLength
);

Parameters

[out] pDeviceName

A pointer to a buffer that receives a NULL-terminated string that represents the name of the underlying kernel-mode device, if the buffer is non-NULL and RetrieveDeviceName is successful.

[in, out] pdwDeviceNameLength

A pointer to a variable that receives the number of characters, including the NULL character, in the device name.

If the buffer at pDeviceName is NULL, the value that the driver supplies is zero. The framework then returns the size, in characters, that is required for the device name string.

If the buffer at pDeviceName is non-NULL, the framework returns the size, in characters, of the device name string.

Return value

RetrieveDeviceName returns S_OK for the following scenarios:

The buffer that the pDeviceName parameter pointed to was non-NULL and large enough to hold the name string, including the NULL character, and the framework successfully copied the string into the supplied buffer and set the variable that is pointed to by pdwDeviceNameLength to the number of characters in the string.
The buffer at pDeviceName was NULL, the driver preset the variable at pdwDeviceNameLength to 0, and the framework set the variable at pdwDeviceNameLength to the number of characters that were required for the string.

RetrieveDeviceName returns HRESULT_FROM_WIN32(ERROR_INSUFFICIENT_BUFFER) to indicate that the supplied buffer was non-NULL and did not contain enough space to hold the device name. The framework sets the variable at pdwDeviceNameLength to the number of characters that are required for the string.

RetrieveDeviceName might also return other HRESULT values.

Remarks

The device name is not the physical device object (PDO) name. Instead, the device name is the name of the reflector. The driver must target all I/O to this device object.

Examples

The following code example shows how to retrieve the name of an underlying kernel-mode device.

    PWSTR deviceName = NULL;
    DWORD deviceNameCch = 0;
    HRESULT hr;
    //
    // Get the length of the device name to allocate a buffer
    //
    hr = m_FxDevice->RetrieveDeviceName(NULL, &deviceNameCch);
    //
    // Allocate the buffer
    //
    deviceName = new WCHAR[deviceNameCch];

    if (deviceName == NULL) {
        hr = E_OUTOFMEMORY;
        goto Exit1;
    }
    //
    // Get the device name
    //
    hr = m_FxDevice->RetrieveDeviceName(deviceName,
                                        &deviceNameCch);

    // Open the device and get the handle

    m_Handle = CreateFile(deviceName, 
                         (GENERIC_READ | GENERIC_WRITE), 
                         0, 
                         NULL, 
                         OPEN_EXISTING, 
                         FILE_FLAG_OVERLAPPED, 
                         NULL);

Requirements

Requirement	Value
End of support	Unavailable in UMDF 2.0 and later.
Target Platform	Desktop
Minimum UMDF version	1.5
Header	wudfddi.h (include Wudfddi.h)
DLL	WUDFx.dll

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