The singleton design pattern ensures that class has single instance and provides a global access to it.
Pattern type - Creational
This pattern has always caused a lot of fuss and there are countless people calling it an anti-pattern. In fact it's just another pattern - IT IS hard to find reasonable application for it but it's doable.
At the implementation level it is important to note that constructor must be private!.
Config objects potentially COULD be implemented using this pattern to ensure that whole application (e.g. webapp) use the same settings.
The biggest trick to deal with sigleton in C++ is to operate properly with static
keyword.