Clean Mysql Insert Data in php

function clean_input($instr) {

     // Note that PHP performs addslashes() on GET/POST data.
     // Avoid double escaping by checking the setting before doing this.
    if(get_magic_quotes_gpc()) {
        $str = stripslashes($instr);
    }
    return mysql_real_escape_string(strip_tags(trim($instr)));
}

$output = clean_input($input);