中文匹配汉字多次失败:配置报错 

[^\u4e00-\u9fa5]

function str_cut($string, $length, $dot = '...')
{
    $strlen = strlen($string);
    if($strlen <= $length) return $string;
    $string = str_replace(array(' ', '&', '"', ''', '“', '”', '—', '<', '>', '·', '…'), array(' ', '&', '"', "'", '“', '”', '—', '<', '>', '·', '…'), $string);
    $strcut = '';
    if(strtolower(CHARSET) == 'utf-8')
    {
        $n = $tn = $noc = 0;
        while($n < $strlen)
        {
            $t = ord($string[$n]);
            if($t == 9 || $t == 10 || (32 <= $t && $t <= 126)) {
                $tn = 1; $n++; $noc++;
            } elseif(194 <= $t && $t <= 223) {
                $tn = 2; $n += 2; $noc += 2;
            } elseif(224 <= $t && $t < 239) {
                $tn = 3; $n += 3; $noc += 2;
            } elseif(240 <= $t && $t <= 247) {
                $tn = 4; $n += 4; $noc += 2;
            } elseif(248 <= $t && $t <= 251) {
                $tn = 5; $n += 5; $noc += 2;
            } elseif($t == 252 || $t == 253) {
                $tn = 6; $n += 6; $noc += 2;
            } else {
                $n++;
            }
            if($noc >= $length) break;
        }
        if($noc > $length) $n -= $tn;
        $strcut = substr($string, 0, $n);
    }
    else
    {
        $dotlen = strlen($dot);
        $maxi = $length - $dotlen - 1;
        for($i = 0; $i < $maxi; $i++)
        {
            $strcut .= ord($string[$i]) > 127 ? $string[$i].$string[++$i] : $string[$i];
        }
    }
    $strcut = str_replace(array('&', '"', "'", '<', '>'), array('&', '"', ''', '<', '>'), $strcut);
    return $strcut.$dot;

}

$str ='中国';
$result = preg_match("/[\x{4e00}-\x{9fa5}]/u",$str); 
print_r($result);