Private Static Variable Initialization (redux)

[tvanriper]

This is actually an added answer to a closed question.

TaylorCoons8798 wrote this:

http://www.cplusplus.com/forum/beginner/125835/

I wanted to add that if you wish to provide a static variable without using an implementation file (.cpp), try playing with the following idiom (within your header file):

inline my_object& get_var()
{
  static my_object ob;
  return obj;
}

This returns a reference to the singular instance of 'ob', maintaining any changes made to its state.

This is a variation of another idiom many people use to help create singletons (classes that only have a single instance):

class my_class
{
public:
  static my_class& get_my_class()
  {
    return _singleton;
  }
private:
  my_class(){}

private:
  static my_class _singleton;
};

The code above makes it so you may only acquire an instance of my_class by calling my_class::get_my_class(), effectively making my_class a singleton.

I hope this is useful.