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<?php $input = array( array( 'tag_name' => array('google', 'Yahoo') ), array( 'tag_name' => array('technology', 'andsuch') ) ); print_r(array_walk(function ($entry) { return $entry['tag_name']; }, $input);
Output for 5.3.0 - 5.4.29
Fatal error: Only variables can be passed by reference in /in/3jZNk on line 13
Process exited with code 255.