getlastmod() for some file

[alcapone]

hey guys.
Now i have a problem, see i am new to PHP and just got to know about getlastmod() function. So the question is how can I get last modification time for some another file?
lets say I have some.php, how do I get it's modification time from main.php? I've tried to do it like:
$a="some.php";
echo date( "D M dS, H:i:s, y", getlastmod($a));
or
echo date( "D M dS, H:i:s, y", getlastmod("some.php"));
but nither of them works for me 🙁
Any help would be highly appreciated,
thank you
Hamper

[rodif_bl]

check out

filemtime("filename.php");