C++ :: Send Info To PHP Webpage?

I was wondering if there was a way for me to send information, say a username and password, to a webpage via a c++ function. I was unsure how exactly to word it, but I did attempt to google it. Here is an example of what I mean.

App starts -> goes to "Https://www.my-site.com/?user=$username&password=$password" -> username/password is valid -> logs them in on desktop app

I do not know much about php, but I am assuming the ?user=$username is setting a variable, correct? I am familiar with sockets, but it seems using the above method, this could be possible without sockets, would it?

Important part:

That is the method that minecraft uses to login players, the question here is what function could I start to send the desktop app to the webpage.

EDIT:: After looking a little more I find that it is probably not possible without sockets, which is fine; however I don't know how to do it still, I would prefer to not use external libraries, such as Curl.