Compiler warnings eliminated:
- VC++: potential use of uninitialized variable
- GCC: potential use of uninitialized variable [-Wmaybe-uninitialized], redundant const on return value [-Wignored-qualifiers]
- CLang: missing override specifier on overloaded virtual function [-Winconsistent-missing-override], function call within typeid() [-Wpotentially-evaluated-expression]