php文件上传时文件名怎么转义

//循环排除替换文件名中的非法字符

$errorchar=array ("-"," ","~","!","@","#","$","%","^","&","(",")","+",","," （","）","？","！","《","》","：","；","——");

foreach($errorchar as $char)

{

    if(strpos($upload_file,$char)){

        $upload_file=str_replace($char,"_",$upload_file);

    }

}