The DLL Project

[pd]

So won't the Player() function return different players on each computer? This would mean that whenever I click, I own the spawned MCV, whereas my opponent thinks that he owns the spawned MCV, therefore desync.

No.
For every computer, the pointer to its respective HouseClass is stored here.
The pointer gets read, and the unit will be created using that pointer.

If you click, it will be created with HouseClass #1 globally, which is stored in your local Player pointer.
If your buddy clicks, the unit will be created with HouseClass #2 globally which is stored in his local Player pointer.

This is exactly how the original game does it, don't worry about it.
All "my routine" does is read from memory btw, I didn't code anything up myself really. It's just a function rather than a static variable to assure you always get the current pointer, in case you left the game and it changed.