PHP如何將字符串轉(zhuǎn)換成utf-8編碼

    PHP如何將字符串轉(zhuǎn)換成utf-8編碼？具體代碼如下：
    // Fixes the encoding to uf8
    function fixEncoding($in_str)
    {
    $cur_encoding = mb_detect_encoding($in_str) ;
    if($cur_encoding == "UTF-8" && mb_check_encoding($in_str,"UTF-8"))
    return $in_str;
    else
    return utf8_encode($in_str);
    } // fixEncoding