Uploading a file that exceed the MAX_FILE_SIZE limit

[ConfusedOfLife]

Is it possible that I change the MAX_FILE_SIZE in the server (within the script preferably!). I can suppress this
warning message by writing error_reporting(0) at the begining of my script, but then how can I find out if any
error/warning was issued from within my script?

[Nightfire]

$maxsize = 102400;
if($file_size > $maxsize){
echo 'File is too big! The max file size is ~100kb<br>'.$default;
exit;
}