There are a couple of ways to do it that pretty easy. If you're using the socket approach you can just have PHP open a client socket and send data to the C++ app. The other way is just to have C++ poll a file that PHP writes to. The latter is quite expensive but easier to implement.

Hmm the first one sounds like something I'd like to have, do you have any tutorials for that? (Both PHP and C++)

http://php.net/sockets

For C++ you might want to look around for forums, there's bound to be a link to a good one. If not, just google C++ sockets there is a veritable shit-ton

Alright thanks for the quick answer!

And does the PHP need to run the socket server or are the C++ app supposed to do that?

Based on what you needed it would make sense for the C++ app to listen (be the server) and PHP to send the data to the server (client)