std::mutex vs std::recursive_mutex as class member

Question

I have seen some people hate on recursive_mutex:

http://www.zaval.org/resources/library/butenhof1.html

But when thinking about how to implement a cl

Answer 1

I'm not going to directly weigh in on the mutex versus recursive_mutex debate, but I thought it would be good to share a scenario where recursive_mutex'es are absolutely critical to the design.

When working with Boost::asio, Boost::coroutine (and probably things like NT Fibers although I'm less familiar with them), it is absolutely essential that your mutexes be recursive even without the design problem of re-entrancy.

The reason is because the coroutine based approach by its very design will suspend execution inside a routine and then subsequently resume it. This means that two top level methods of a class might "be being called at the same time on the same thread" without any sub calls being made.