register_setting() │ WP 2.7.0

Register a setting and its data.

Hooks from the function

Return

null. Nothing.

Usage

register_setting( $option_group, $option_name, $args );
$option_group(string) (required)
A settings group name. Should correspond to an allowed option key name.
Default: allowed option key names include 'general', 'discussion', 'media', 'reading', 'writing', and 'options'
$option_name(string) (required)
The name of an option to sanitize and save.
$args(array)

Data used to describe the setting when registered.

Default: array()

  • type(string)
    The type of data associated with this setting. Valid values are 'string', 'boolean', 'integer', 'number', 'array', and 'object'.

  • description(string)
    A description of the data attached to this setting.

  • sanitize_callback(callable)
    A callback function that sanitizes the option's value.

  • show_in_rest(true|false|array)
    Whether data associated with this setting should be included in the REST API. When registering complex settings, this argument may optionally be an array with a 'schema' key.

  • default(mixed)
    Default value when calling get_option().

Notes

  • Global. Array. $new_allowed_options
  • Global. Array. $wp_registered_settings

Changelog

Since 2.7.0 Introduced.
Since 3.0.0 The misc option group was deprecated.
Since 3.5.0 The privacy option group was deprecated.
Since 4.7.0 $args can be passed to set flags on the setting, similar to register_meta().
Since 5.5.0 $new_whitelist_options was renamed to $new_allowed_options. Please consider writing more inclusive code.

Code of register_setting() WP 5.9.3

wp-includes/option.php 
function register_setting( $option_group, $option_name, $args = array() ) {
	global $new_allowed_options, $wp_registered_settings;

	/*
	 * In 5.5.0, the `$new_whitelist_options` global variable was renamed to `$new_allowed_options`.
	 * Please consider writing more inclusive code.
	 */
	$GLOBALS['new_whitelist_options'] = &$new_allowed_options;

	$defaults = array(
		'type'              => 'string',
		'group'             => $option_group,
		'description'       => '',
		'sanitize_callback' => null,
		'show_in_rest'      => false,
	);

	// Back-compat: old sanitize callback is added.
	if ( is_callable( $args ) ) {
		$args = array(
			'sanitize_callback' => $args,
		);
	}

	/**
	 * Filters the registration arguments when registering a setting.
	 *
	 * @since 4.7.0
	 *
	 * @param array  $args         Array of setting registration arguments.
	 * @param array  $defaults     Array of default arguments.
	 * @param string $option_group Setting group.
	 * @param string $option_name  Setting name.
	 */
	$args = apply_filters( 'register_setting_args', $args, $defaults, $option_group, $option_name );

	$args = wp_parse_args( $args, $defaults );

	// Require an item schema when registering settings with an array type.
	if ( false !== $args['show_in_rest'] && 'array' === $args['type'] && ( ! is_array( $args['show_in_rest'] ) || ! isset( $args['show_in_rest']['schema']['items'] ) ) ) {
		_doing_it_wrong( __FUNCTION__, __( 'When registering an "array" setting to show in the REST API, you must specify the schema for each array item in "show_in_rest.schema.items".' ), '5.4.0' );
	}

	if ( ! is_array( $wp_registered_settings ) ) {
		$wp_registered_settings = array();
	}

	if ( 'misc' === $option_group ) {
		_deprecated_argument(
			__FUNCTION__,
			'3.0.0',
			sprintf(
				/* translators: %s: misc */
				__( 'The "%s" options group has been removed. Use another settings group.' ),
				'misc'
			)
		);
		$option_group = 'general';
	}

	if ( 'privacy' === $option_group ) {
		_deprecated_argument(
			__FUNCTION__,
			'3.5.0',
			sprintf(
				/* translators: %s: privacy */
				__( 'The "%s" options group has been removed. Use another settings group.' ),
				'privacy'
			)
		);
		$option_group = 'reading';
	}

	$new_allowed_options[ $option_group ][] = $option_name;

	if ( ! empty( $args['sanitize_callback'] ) ) {
		add_filter( "sanitize_option_{$option_name}", $args['sanitize_callback'] );
	}
	if ( array_key_exists( 'default', $args ) ) {
		add_filter( "default_option_{$option_name}", 'filter_default_option', 10, 3 );
	}

	/**
	 * Fires immediately before the setting is registered but after its filters are in place.
	 *
	 * @since 5.5.0
	 *
	 * @param string $option_group Setting group.
	 * @param string $option_name  Setting name.
	 * @param array  $args         Array of setting registration arguments.
	 */
	do_action( 'register_setting', $option_group, $option_name, $args );

	$wp_registered_settings[ $option_name ] = $args;
}

Settings API