Why does this code invoke the copy constructor?

Question

I'm a C++ noob so I can't figure out why the line in Logger.cpp invokes the copy constructor...

Logger.h:

class Logger {
    public:
    Logger();
    ~Logger();
};

Logger LOGGER;

Logger.cpp:

Logger LOGGER = Logger(); // Copy constructor here

Answer 1

The statement Logger() creates an anonymous temporary object.

LOGGER = Logger() copies that anonymous temporary into the object LOGGER. The copy constructor avoids having to construct LOGGER as something other than a copy of that temporary.

The compiler is allowed to optimize away this copy, but it's not required to. More here.

If you want to construct the object directly, just say Logger LOGGER;.