I'm developing an augmented reality application and I'm supposed to use the ALVAR library for AR marker detection. I use Unity as the game engine and unfortunately it doesn't support C++. Is there any possible way to use the C++ library as a DLL?
You should be a little bit more versatile, you should search resources from other people, maybe by using this it's a good start:
It says Unity 3.5.5 Pro, don't worry about this, because Unity 5 has all Plugins features from Pro lower versions.
And the Unity Import Script API should translate it to the newest code! Maybe you will see some compiler warnings.