WdfRegistryQueryString - NtDoc
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// wdfregistry.h
NTSTATUS WdfRegistryQueryString(
[in] WDFKEY Key,
[in] PCUNICODE_STRING ValueName,
[in] WDFSTRING String
);
View the official Windows Driver Kit DDI referenceNo description available.
[Applies to KMDF and UMDF]
The WdfRegistryQueryString method retrieves the string data that is currently assigned to a specified registry string value and assigns the string to a specified framework string object.
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.
String [in]A handle to a framework string object. The framework will assign the registry value's string data to this object.
WdfRegistryQueryString returns STATUS_SUCCESS if the operation succeeds. Otherwise, the method might return one of the following values:
| Return code | Description |
|---|---|
| STATUS_INVALID_DEVICE_REQUEST | WdfRegistryQueryString 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_SZ. |
| 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 WdfRegistryQueryString 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.
To obtain a string from a string object, your driver can call WdfStringGetUnicodeString.
For more information about registry-key objects, see Using the Registry in Framework-Based Drivers.
The following code example creates a string object, retrieves string data from a registry key, and obtains the string data from the string object.
UNICODE_STRING str;
WDFSTRING string;
NTSTATUS status;
DECLARE_CONST_UNICODE_STRING(valueName, STRING_VALUE_NAME);
status = WdfStringCreate(
NULL,
WDF_NO_OBJECT_ATTRIBUTES,
&string
);
if (NT_SUCCESS(status)) {
status = WdfRegistryQueryString(
Key,
&valueName,
string
);
if (NT_SUCCESS(status)) {
WdfStringGetUnicodeString(
string,
&str
);
}
}