$filename = 'd:\\data.txt';
if (touch($filename, mktime(0, 0, 0, 12, 31, 1999)))
echo "$filename modified to current date & time:".date("m/d/Y H:i:s", filemtime($filename));
else
echo "Error <br />";
/*
run:
d:\data.txt modified to current date & time:12/31/1999 00:00:00
*/