RegFlushKey function (winreg.h)
Writes all the attributes of the specified open registry key into the registry.
Syntax
LSTATUS RegFlushKey(
[in] HKEY hKey
);
Parameters
[in] hKey
A handle to an open registry key. The key must have been opened with the KEY_QUERY_VALUE access right. For more information, see Registry Key Security and Access Rights.
This handle is returned by the RegCreateKeyEx, RegCreateKeyTransacted, RegOpenKeyEx, or RegOpenKeyTransacted function. It can also be one of the following predefined keys:
- HKEY_CLASSES_ROOT
- HKEY_CURRENT_CONFIG
- HKEY_CURRENT_USER
- HKEY_LOCAL_MACHINE
- HKEY_PERFORMANCE_DATA
- HKEY_USERS
Return value
If the function succeeds, the return value is ERROR_SUCCESS.
If the function fails, the return value is a nonzero error code defined in Winerror.h. You can use the FormatMessage function with the FORMAT_MESSAGE_FROM_SYSTEM flag to get a generic description of the error.
Remarks
Calling RegFlushKey is an expensive operation that significantly affects system-wide performance as it consumes disk bandwidth and blocks modifications to all keys by all processes in the registry hive that is being flushed until the flush operation completes. RegFlushKey should only be called explicitly when an application must guarantee that registry changes are persisted to disk immediately after modification. All modifications made to keys are visible to other processes without the need to flush them to disk.
Alternatively, the registry has a 'lazy flush' mechanism that flushes registry modifications to disk at regular intervals of time. In addition to this regular flush operation, registry changes are also flushed to disk at system shutdown. Allowing the 'lazy flush' to flush registry changes is the most efficient way to manage registry writes to the registry store on disk.
The RegFlushKey function returns only when all the data for the hive that contains the specified key has been written to the registry store on disk.
The RegFlushKey function writes out the data for other keys in the hive that have been modified since the last lazy flush or system start.
After RegFlushKey returns, use RegCloseKey to close the handle to the registry key.
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client | Windows 2000 Professional [desktop apps only] |
| Minimum supported server | Windows 2000 Server [desktop apps only] |
| Target Platform | Windows |
| Header | winreg.h (include Windows.h) |
| Library | Advapi32.lib |
| DLL | Advapi32.dll |