How to enable PHP short tags?

I have a web application on a Linux server which starts with `<?` I needed to copy this application to a windows environment and everything is working fine except that an SQL statement is being rendered differently. I don't know if this has to do with the script beginning with `<?php` instead of `<?` because I don't know from where to enable the `<?` from the `PHP.ini` so I changed it to `<?php` I know that these 2 statements are supposed to mean the same but I need to test it with `<?` in order to ensure that the application is exactly the same. This way I can eliminate another possibility. Thanks