PHP - My code never enters in if statement

This code does not enter in if statement.

<?php
echo $result . "before";
echo gettype($result), "\n";

if($result == "T")
{
    //$_SESSION["user_id"] = $user_id;
    //$_SESSION["email"]     = $email;
    echo "Session variables are set.";
     echo $result;
}
echo $result . "after";

?>

When I execute it, it prints:

T beforestring T after

What is the reason?