str_shuffle函数要求PHP的配置吗？一直提示第二行语法错误
$string = join('',array_merge(range(0,9),range('a','z'),range('A','Z')));
$text=str_shuffle($string){0};
imagettftext($img,$size,$angle,$x,$y,$randcolor,$font,$text);
header("content-type:image/png");
imagepng($img);
imagedestroy($img);
