WordPress at a glance
function is not described

_links_add_base() WP 2.7.0

Callback to add a base url to relative links in passed content.

  • Global. String. $_links_add_base

No Hooks.

Return

String. The processed link.

Usage

_links_add_base( $m );
$m(string) (required)
The matched link.

Code of links add base: wp-includes/formatting.php WP 5.2.2

<?php
function _links_add_base( $m ) {
	global $_links_add_base;
	//1 = attribute name  2 = quotation mark  3 = URL
	return $m[1] . '=' . $m[2] .
		( preg_match( '#^(\w{1,20}):#', $m[3], $protocol ) && in_array( $protocol[1], wp_allowed_protocols() ) ?
			$m[3] :
			WP_Http::make_absolute_url( $m[3], $_links_add_base )
		)
		. $m[2];
}