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AsmSource : Assembly Language Programming

Dos Source

Win Source





The RegCloseKey function releases a handle to the specified registry key.

LONG RegCloseKey(
  HKEY hKey   // handle to key to close


[in] Handle to the open key to close.

Return Values

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.


The handle for a specified key should not be used after it has been closed, because it will no longer be valid. Key handles should not be left open any longer than necessary.

The RegCloseKey function does not necessarily write information to the registry before returning; it can take as much as several seconds for the cache to be flushed to the hard disk. If an application must explicitly write registry information to the hard disk, it can use the RegFlushKey function. RegFlushKey, however, uses many system resources and should be called only when necessary.

Windows 95/98: No registry subkey or value name may exceed 255 characters.


  Windows NT/2000: Requires Windows NT 3.1 or later.
  Windows 95/98: Requires Windows 95 or later.
  Header: Declared in Winreg.h; include Windows.h.
  Library: Use Advapi32.lib.

See Also

Registry Overview, Registry Functions, RegCreateKey, RegCreateKeyEx, RegDeleteKey, RegFlushKey, RegOpenKey, RegOpenKeyEx, RegSetValue, RegSetValueEx