WdfRegistryQueryULong method

[Applies to KMDF and UMDF]

The WdfRegistryQueryULong method retrieves the unsigned long word (REG_DWORD) data that is currently assigned to a specified registry value and copies the data to a specified location.

Syntax


NTSTATUS WdfRegistryQueryULong(
  [in]   WDFKEY Key,
  [in]   PCUNICODE_STRING ValueName,
  [out]  PULONG Value
);

Parameters

Key [in]

A handle to a registry-key object that represents an opened registry key.

ValueName [in]

A pointer to a UNICODE_STRING structure that contains a name for the registry value.

Value [out]

A pointer to a location that receives the data that is assigned to the registry value that ValueName specifies.

Return value

WdfRegistryQueryULong returns STATUS_SUCCESS if the operation succeeds. Otherwise, the method might return one of the following values:

Return codeDescription
STATUS_INVALID_DEVICE_REQUEST

WdfRegistryQueryULong was not called at IRQL = PASSIVE_LEVEL.

STATUS_INVALID_PARAMETER

An invalid parameter was specified.

STATUS_INSUFFICIENT_RESOURCES

There was insufficient memory to complete the operation.

STATUS_ACCESS_DENIED

The driver did not open the registry key with KEY_QUERY_VALUE, KEY_READ, or KEY_ALL_ACCESS access.

STATUS_OBJECT_TYPE_MISMATCH

The data type of the registry value that the ValueName parameter specified was not REG_DWORD.

STATUS_OBJECT_NAME_NOT_FOUND

The registry value was not available.

 

This method also might return other NTSTATUS values.

A bug check occurs if the driver supplies an invalid object handle.

Remarks

For more information about registry-key objects, see Using the Registry in WDF Drivers.

Examples

The following code example retrieves the data that is currently assigned to the NumberOfThings value.


NTSTATUS  status;
ULONG  value;
DECLARE_CONST_UNICODE_STRING(valueName, L"NumberOfThings");

status = WdfRegistryQueryULong(
                               hKey,
                               &valueName,
                               &value
                               );

Requirements

Minimum KMDF version

1.0

Minimum UMDF version

2.0

Header

Wdfregistry.h (include Wdf.h)

Library

Wdf01000.sys (KMDF);
WUDFx02000.dll (UMDF)

IRQL

PASSIVE_LEVEL

DDI compliance rules

DriverCreate, KmdfIrql, KmdfIrql2

See also

UNICODE_STRING
WdfRegistryQueryMemory
WdfRegistryQueryMultiString
WdfRegistryQueryString
WdfRegistryQueryUnicodeString
WdfRegistryQueryValue

 

 

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