$filename = 'd:\\data.txt';
if (touch($filename, mktime(3, 42, 17,
date("m", filemtime($filename)),
date("d", filemtime($filename)),
date("Y", filemtime($filename)) )))
echo "$filename date & time: ".date("m/d/Y H:i:s", filemtime($filename));
else
echo "Error <br />";
/*
run:
d:\data.txt date & time: 12/31/1999 03:42:17
*/