php.ini限制技巧$ _FILES ['userfile'] ['size']

Question

In php.ini I have set:

post_max_size = 101M
upload_max_filesize = 101M
memory_limit = 128M

a php upload form uses can upload file up to 100M a script will check if it doesn't exceed 100M

$img_size = $_FILES['bestand']['size'];
if ($img_size > MAX_EXTRA_FILE_FILE_SIZE){
$errors['tooBig'] = 1;

However, if a user uploads 125M, the server returns the message: PHP Warning: POST Content-Length of ########### bytes exceeds the limit of ... and the $error['tooBig'] will lose its value and no error message will be returned to the user. Of course, i can just increase the ini.php:post_max_size endlessly, but even than a use could upload even larger files.

How do i tackle this?