what is the best way to use global variables in c++?

Question

For me, I usually make a global class with all members static. All other classes will inherit from this global class.

I wonder if this is a good practice?

Anybody got any suggestions?

Answer 1

Generally try to avoid global variables as they introduce global state. And with global state you do not have referential transparency. Referential transparency is a good thing and global state is a bad thing. Global state makes unit tests pretty pointless for example.

When you have to though, I'd agree that most of the time the method you mentioned is fine. You can also declare the global variable in any .cpp file and then have in your .h file an extern to that global variable.

Answer 2

Best way? Carefully... :-)