WdfRegistryQueryMemory - NtDoc
Native API online documentation, based on the System Informer
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headers
// wdfregistry.h
NTSTATUS WdfRegistryQueryMemory(
[in] WDFKEY Key,
[in] PCUNICODE_STRING ValueName,
[in] POOL_TYPE PoolType,
[in, optional] PWDF_OBJECT_ATTRIBUTES MemoryAttributes,
[out] WDFMEMORY *Memory,
[out, optional] PULONG ValueType
);
View the official Windows Driver Kit DDI referenceNo description available.
[Applies to KMDF and UMDF]
The WdfRegistryQueryMemory method retrieves the data that is currently assigned to a specified registry value, stores the data in a framework-allocated buffer, and creates a framework memory object to represent the buffer.
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 value name.
PoolType [in]A POOL_TYPE-typed value that specifies the type of memory to be allocated for the data buffer.
MemoryAttributes [in, optional]A pointer to a WDF_OBJECT_ATTRIBUTES structure that contains object attributes for the new memory object. This parameter is optional and can be WDF_NO_OBJECT_ATTRIBUTES.
Memory [out]A pointer to a location that receives a handle to the new memory object.
ValueType [out, optional]A pointer to a location that receives the data type. For a list of data type values, see the Type member of KEY_VALUE_BASIC_INFORMATION. This pointer is optional and can be NULL.
WdfRegistryQueryMemory returns STATUS_SUCCESS if the operation succeeds. Otherwise, the method might return one of the following values:
| Return code | Description |
|---|---|
| STATUS_INVALID_DEVICE_REQUEST | WdfRegistryQueryMemory was not called at IRQL = PASSIVE_LEVEL. |
| STATUS_INVALID_PARAMETER | An invalid parameter was specified. |
| STATUS_INSUFFICIENT_RESOURCES | A memory object could not be allocated. |
| STATUS_ACCESS_DENIED | The driver did not open the registry key with KEY_QUERY_VALUE, KEY_READ, or KEY_ALL_ACCESS access. |
| STATUS_OBJECT_NAME_NOT_FOUND | The registry value was not available. |
| STATUS_RESOURCE_DATA_NOT_FOUND | The registry value exists under the specified key, but is empty. |
For a list of other return values that the WdfRegistryQueryMemory method might return, see Framework Object Creation Errors.
This method also might return other NTSTATUS values.
A bug check occurs if the driver supplies an invalid object handle.
When a driver calls WdfRegistryQueryMemory, the framework allocates a buffer that is large enough to hold the specified registry value's data. After WdfRegistryQueryMemory returns, the driver can call WdfMemoryGetBuffer to obtain a pointer to the buffer and the buffer's size.
For more information about registry-key objects, see Using the Registry in Framework-Based Drivers.
The following code example retrieves the data that is assigned to the MyValueName value and then obtains the data's address and size.
WDFMEMORY memory;
size_t size;
PUCHAR pBuf;
NTSTATUS status;
ULONG type;
DECLARE_CONST_UNICODE_STRING(valueName1, L"MyValueName");
status = WdfRegistryQueryMemory(
Key,
&valueName1,
PagedPool,
NULL,
&memory,
&type
);
pBuf = (PUCHAR)WdfMemoryGetBuffer(
memory,
&size
);