Returns the regexp for common whitespace characters.


By default, spaces include new lines, tabs, nbsp entities, and the UTF-8 nbsp. This is designed to replace the PCRE \s sequence. In https://core.trac.wordpress.org/ticket/22692, that sequence was found to be unreliable due to random inclusion of the A0 byte.


(string) The spaces regexp.


File: wp-includes/formatting.php

function wp_spaces_regexp() {
	static $spaces = '';

	if ( empty( $spaces ) ) {
		 * Filters the regexp for common whitespace characters.
		 * This string is substituted for the \s sequence as needed in regular
		 * expressions. For websites not written in English, different characters
		 * may represent whitespace. For websites not encoded in UTF-8, the 0xC2 0xA0
		 * sequence may not be in use.
		 * @since WP-4.0.0
		 * @param string $spaces Regexp pattern for matching common whitespace characters.
		$spaces = apply_filters( 'wp_spaces_regexp', '[\r\n\t ]|\xC2\xA0| ' );

	return $spaces;


Version Description
WP-4.0.0 Introduced.