In your loop, you are opening and closing the file on each iteration. You should open the csv file before the loop, add to it, then close it when the loop is done.
Also, you should use ===
or ==
for comparisons.
$row = 1;
if (($handle = fopen(getHistory("T","2010-06-1"), "r")) !== FALSE) {
// This truncates the file to zero length
// so, we only need to do this once, before the loop
$fp = fopen('t.csv', 'w');
while (($data = fgetcsv($handle, 1000, ",")) !== FALSE) {
$num = count($data);
if($row === 1){array_unshift($data,"Symbol"); }
else { array_unshift($data, "T"); }
fputcsv($fp, $data);
$row++;
}
// Close it once we're all done
fclose($fp);
}
fclose($handle);