get_network_option

function delete_all_user_settings() {
	$user_id = get_current_user_id();
	if ( ! $user_id ) {
		return;
	}

	update_user_option( $user_id, 'user-settings', '', false );
	setcookie( 'wp-settings-' . $user_id, ' ', time() - YEAR_IN_SECONDS, SITECOOKIEPATH );
}

/**
 * Retrieve an option value for the current network based on name of option.
 *
 * @since 2.8.0
 * @since 4.4.0 The `$use_cache` parameter was deprecated.
 * @since 4.4.0 Modified into wrapper for get_network_option()
 *
 * @see get_network_option()
 *
 * @param string $option     Name of the option to retrieve. Expected to not be SQL-escaped.
 * @param mixed  $default    Optional. Value to return if the option doesn't exist. Default false.
 * @param bool   $deprecated Whether to use cache. Multisite only. Always set to true.
 * @return mixed Value set for the option.
 */
function get_site_option( $option, $default = false, $deprecated = true ) {
	return get_network_option( null, $option, $default );
}

/**
 * Adds a new option for the current network.
 *
 * Existing options will not be updated. Note that prior to 3.3 this wasn't the case.
 *
 * @since 2.8.0
 * @since 4.4.0 Modified into wrapper for add_network_option()
 *
 * @see add_network_option()
 *
 * @param string $option Name of the option to add. Expected to not be SQL-escaped.
 * @param mixed  $value  Option value, can be anything. Expected to not be SQL-escaped.
 * @return bool True if the option was added, false otherwise.
 */
function add_site_option( $option, $value ) {
	return add_network_option( null, $option, $value );
}

/**
 * Removes a option by name for the current network.
 *
 * @since 2.8.0
 * @since 4.4.0 Modified into wrapper for delete_network_option()
 *
 * @see delete_network_option()
 *
 * @param string $option Name of the option to delete. Expected to not be SQL-escaped.
 * @return bool True if the option was deleted, false otherwise.
 */
function delete_site_option( $option ) {
	return delete_network_option( null, $option );
}

/**
 * Updates the value of an option that was already added for the current network.
 *
 * @since 2.8.0
 * @since 4.4.0 Modified into wrapper for update_network_option()
 *
 * @see update_network_option()
 *
 * @param string $option Name of the option. Expected to not be SQL-escaped.
 * @param mixed  $value  Option value. Expected to not be SQL-escaped.
 * @return bool True if the value was updated, false otherwise.
 */
function update_site_option( $option, $value ) {
	return update_network_option( null, $option, $value );
}

/**
 * Retrieves a network's option value based on the option name.
 *
 * @since 4.4.0
 *
 * @see get_option()
 *
 * @global wpdb $wpdb WordPress database abstraction object.
 *
 * @param int    $network_id ID of the network. Can be null to default to the current network ID.
 * @param string $option     Name of the option to retrieve. Expected to not be SQL-escaped.
 * @param mixed  $default    Optional. Value to return if the option doesn't exist. Default false.
 * @return mixed Value set for the option.
 */
function get_network_option( $network_id, $option, $default = false ) {
	global $wpdb;

	if ( $network_id && ! is_numeric( $network_id ) ) {
		return false;
	}

	$network_id = (int) $network_id;

	// Fallback to the current network if a network ID is not specified.
	if ( ! $network_id ) {
		$network_id = get_current_network_id();
	}

	/**
	 * Filters the value of an existing network option before it is retrieved.
	 *
	 * The dynamic portion of the hook name, `$option`, refers to the option name.
	 *
	 * Returning a truthy value from the filter will effectively short-circuit retrieval
	 * and return the passed value instead.
	 *
	 * @since 2.9.0 As 'pre_site_option_' . $key
	 * @since 3.0.0
	 * @since 4.4.0 The `$option` parameter was added.