is_child_theme()

Whether a child theme is in use.

Return

(bool) True if a child theme is in use, false otherwise.

Source

File: wp-includes/theme.php 

function is_child_theme() {
	return ( TEMPLATEPATH !== STYLESHEETPATH );
}

Used By

Used By Description
wp-admin/includes/class-wp-site-health.php: WP_Site_Health::get_test_theme_version()

Test if themes are outdated, or unnecessary.
wp-includes/class-wp-customize-manager.php: WP_Customize_Manager::prepare_starter_content_attachments()

Prepare starter content attachments.
wp-includes/theme.php: get_editor_stylesheets()

Retrieves any registered editor stylesheet URLs.
wp-includes/theme.php: validate_current_theme()

Checks that the current theme has ‘index.php’ and ‘style.css’ files.

Changelog

Version Description
3.0.0 Introduced.

© 2003–2021 WordPress Foundation
Licensed under the GNU GPLv2+ License.
https://developer.wordpress.org/reference/functions/is_child_theme