add_option

	/**
	 * Fires after the value of a specific option has been successfully updated.
	 *
	 * The dynamic portion of the hook name, `$option`, refers to the option name.
	 *
	 * @since 2.0.1
	 * @since 4.4.0 The `$option` parameter was added.
	 *
	 * @param mixed  $old_value The old option value.
	 * @param mixed  $value     The new option value.
	 * @param string $option    Option name.
	 */
	do_action( "update_option_{$option}", $old_value, $value, $option );

	/**
	 * Fires after the value of an option has been successfully updated.
	 *
	 * @since 2.9.0
	 *
	 * @param string $option    Name of the updated option.
	 * @param mixed  $old_value The old option value.
	 * @param mixed  $value     The new option value.
	 */
	do_action( 'updated_option', $option, $old_value, $value );

	return true;
}

/**
 * Adds a new option.
 *
 * You do not need to serialize values. If the value needs to be serialized,
 * then it will be serialized before it is inserted into the database.
 * Remember, resources cannot be serialized or added as an option.
 *
 * You can create options without values and then update the values later.
 * Existing options will not be updated and checks are performed to ensure that you
 * aren't adding a protected WordPress option. Care should be taken to not name
 * options the same as the ones which are protected.
 *
 * @since 1.0.0
 *
 * @global wpdb $wpdb WordPress database abstraction object.
 *
 * @param string      $option     Name of the option to add. Expected to not be SQL-escaped.
 * @param mixed       $value      Optional. Option value. Must be serializable if non-scalar.
 *                                Expected to not be SQL-escaped.
 * @param string      $deprecated Optional. Description. Not used anymore.
 * @param string|bool $autoload   Optional. Whether to load the option when WordPress starts up.
 *                                Default is enabled. Accepts 'no' to disable for legacy reasons.
 * @return bool True if the option was added, false otherwise.
 */
function add_option( $option, $value = '', $deprecated = '', $autoload = 'yes' ) {
	global $wpdb;

	if ( ! empty( $deprecated ) ) {
		_deprecated_argument( __FUNCTION__, '2.3.0' );
	}

	$option = trim( $option );
	if ( empty( $option ) ) {
		return false;
	}

	/*
	 * Until a proper _deprecated_option() function can be introduced,
	 * redirect requests to deprecated keys to the new, correct ones.
	 */
	$deprecated_keys = array(
		'blacklist_keys'    => 'disallowed_keys',
		'comment_whitelist' => 'comment_previously_approved',
	);

	if ( ! wp_installing() && isset( $deprecated_keys[ $option ] ) ) {
		_deprecated_argument(
			__FUNCTION__,
			'5.5.0',
			sprintf(
				/* translators: 1: Deprecated option key, 2: New option key. */
				__( 'The "%1$s" option key has been renamed to "%2$s".' ),
				$option,
				$deprecated_keys[ $option ]
			)
		);
		return add_option( $deprecated_keys[ $option ], $value, $deprecated, $autoload );
	}

	wp_protect_special_option( $option );