* AP_REGKEY_CLASSES_ROOT * AP_REGKEY_CURRENT_CONFIG * AP_REGKEY_CURRENT_USER * AP_REGKEY_LOCAL_MACHINE * AP_REGKEY_USERS * AP_REGKEY_PERFORMANCE_DATA * AP_REGKEY_DYN_DATA *
* APR_READ open key for reading * APR_WRITE open key for writing * APR_CREATE create the key if it doesn't exist * APR_EXCL return error if APR_CREATE and key exists *