Cantidad de dias entre 2 fechaS

[chalchis]

$target = mktime(7,0,0,$month,$day,$year);
$diff =$target - time();
$days = ($diff - ($diff % 86400)) / 86400;
$diff = $diff - ($days * 86400);
$restante = "";
$month = $days-30;
if ($month <=0 ){
$month =0;
}
else{
$month = 1;
}
if ($days< 0 )
$restante = abs($restante. $days);
if ($restante =="")
{

$car=1;
echo $car;
}
else
{
$dias= $restante;
echo $dias;
}