[in] Specifies special options for the key. This parameter can be one of the following values. Value Meaning
REG_OPTION_NON_VOLATILE This key is not volatile; this is the default. The information is stored in a file and is preserved when the system is restarted. The RegSaveKey function saves keys that are not volatile.
REG_OPTION_VOLATILE Windows NT/2000/XP: All keys created by the function are volatile. The information is stored in memory and is not preserved when the corresponding registry hive is unloaded. For HKEY_LOCAL_MACHINE, this occurs when the system is shut down. For registry keys loaded by the RegLoadKey function, this occurs when the corresponding RegUnloadKey is performed. The RegSaveKey function does not save volatile keys. This flag is ignored for keys that already exist.
Windows 95/98/Me: This value is ignored. If REG_OPTION_VOLATILE is specified, the RegCreateKeyEx function creates nonvolatile keys and returns ERROR_SUCCESS.
REG_OPTION_BACKUP_RESTORE Windows NT/2000/XP: If this flag is set, the function ignores the samDesired parameter and attempts to open the key with the access required to backup or restore the key. If the calling thread has the SE_BACKUP_NAME privilege enabled, the key is opened with ACCESS_SYSTEM_SECURITY and KEY_READ access. If the calling thread has the SE_RESTORE_NAME privilege enabled, the key is opened with ACCESS_SYSTEM_SECURITY and KEY_WRITE access. If both privileges are enabled, the key has the combined accesses for both privileges.