is_404()

Determines whether the query has resulted in a 404 (returns no results).

Description

For more information on this and similar theme functions, check out the Conditional Tags article in the Theme Developer Handbook.

Return

(bool) Whether the query is a 404 error.

Source

File: wp-includes/query.php 

function is_404() {
	global $wp_query;

	if ( ! isset( $wp_query ) ) {
		_doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
		return false;
	}

	return $wp_query->is_404();
}

Uses

Uses Description
wp-includes/l10n.php: __()

Retrieve the translation of $text.
wp-includes/class-wp-query.php: WP_Query::is_404()

Is the query a 404 (returns no results)?
wp-includes/functions.php: _doing_it_wrong()

Mark something as being incorrectly called.

Used By

Used By Description
wp-includes/embed.php: print_embed_comments_button()

Prints the necessary markup for the embed comments button.
wp-includes/embed.php: print_embed_sharing_button()

Prints the necessary markup for the embed sharing button.
wp-includes/embed.php: print_embed_sharing_dialog()

Prints the necessary markup for the embed sharing dialog.
wp-includes/general-template.php: wp_get_document_title()

Returns document title for the current page.
wp-includes/general-template.php: wp_title()

Display or retrieve page title for all areas of blog.
wp-includes/class-wp.php: WP::handle_404()

Set the Headers for 404, if nothing is found for requested URL.
wp-includes/query.php: wp_old_slug_redirect()

Redirect old slugs to the correct permalink.
wp-includes/post-template.php: get_body_class()

Retrieves an array of the class names for the body element.
wp-includes/canonical.php: redirect_canonical()

Redirects incoming links to the proper URL based on the site url.
wp-includes/canonical.php: wp_redirect_admin_locations()

Redirects a variety of shorthand URLs to the admin.
wp-includes/ms-functions.php: maybe_redirect_404()

Correct 404 redirects when NOBLOGREDIRECT is defined.

Changelog

Version Description
1.5.0 Introduced.

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Licensed under the GNU GPLv2+ License.
https://developer.wordpress.org/reference/functions/is_404