Thread safe lazy construction of a singleton in C++

Question

Is there a way to implement a singleton object in C++ that is:

1. Lazily constructed in a thread safe manner (two threads might simultaneously be the first user o

Answer 1

You can't do it without any static variables, however if you are willing to tolerate one, you can use Boost.Thread for this purpose. Read the "one-time initialisation" section for more info.

Then in your singleton accessor function, use boost::call_once to construct the object, and return it.