WordPress デバッグ debug_log

    function debug_log($msg) { // debug message
        $msg = gmdate('Y/m/d H:i:s', current_time('timestamp')) . ' ' . $msg . "\n";
        $log_file = dirname(__FILE__) . DIRECTORY_SEPARATOR . 'log' . DIRECTORY_SEPARATOR . 'debug.log';
        $f = debug_fopen($log_file, 'a+');
        debug_fwrite($f, $msg);
        debug_fclose($f);
    }

    function item_search() { // Retrieve items HTML for output
        $output = '
test
';

        $this->debug_log("enter item_search()");

        return $output;
    }