WdfRegistryQueryULong function (wdfregistry.h)

Article
04/18/2022

[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

[in] Key

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

[in] ValueName

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

[out] Value

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 code	Description
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

Requirement	Value
Target Platform	Universal
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(kmdf), KmdfIrql(kmdf), KmdfIrql2(kmdf), KmdfIrqlExplicit(kmdf)

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