Description:
------------
On Windows, flock() only locks the first byte of the file, so that
fseeking beyond that first byte allows accessing the file
contents.

Test script:
---------------
<?php
$filename = __FILE__;
$stream1 = fopen($filename, "r");
var_dump(flock($stream1, LOCK_EX));
$stream2 = fopen($filename, "r");
var_dump(fread($stream2, 5));
fseek($stream2, 1);
var_dump(fread($stream2, 4));
?>


Expected result:
----------------
bool(true)
bool(false)
bool(false)


Actual result:
--------------
bool(true)
bool(false)
string(4) "?php"