var $sendmail_path="/usr/lib/sendmail";
var $sendmail_arguments="";
Function SendMail($to, $subject, $body, $headers, $return_path)
    {
        $command=$this->sendmail_path." -t -i";
        switch($this->bulk_mail ? $this->bulk_mail_delivery_mode : $this->delivery_mode)
        {
            case SENDMAIL_DELIVERY_DEFAULT:
            case SENDMAIL_DELIVERY_INTERACTIVE:
            case SENDMAIL_DELIVERY_BACKGROUND:
            case SENDMAIL_DELIVERY_QUEUE:
            case SENDMAIL_DELIVERY_DEFERRED:
                break;
            default:
                return($this->OutputError("it was specified an unknown sendmail delivery mode"));
        }
        if($this->delivery_mode!=SENDMAIL_DELIVERY_DEFAULT)
            $command.=" -od".$this->delivery_mode;
        if(strlen($return_path))
            $command.=" -f '".preg_replace("/'/", "'\\''",$return_path)."'";
        if(strlen($this->sendmail_arguments))
            $command.=" ".$this->sendmail_arguments;
        if(!($pipe=@popen($command,"w")))
            return($this->OutputPHPError("it was not possible to open sendmail input pipe", $php_errormsg));
        if(strlen($headers))
            $headers.="\n";
        if(!@fputs($pipe,"To: ".$to."\nSubject: ".$subject."\n".$headers."\n")
        || !@fputs($pipe,$body)
        || !@fflush($pipe))
            return($this->OutputPHPError("it was not possible to write sendmail input pipe", $php_errormsg));
        pclose($pipe);
        return("");
    }