C++ singleton vs. global static object

Question

A friend of mine today asked me why should he prefer use of singleton over global static object? The way I started it to explain was that the singleton can have state vs. s

Answer 1

In C++, the order of instantiation of static objects in different compilation units is undefined. Thus it's possible for one global to reference another which is not constructed, blowing up your program. The singleton pattern removes this problem by tying construction to a static member function or free function.

There's a decent summary here.