Observe size of lockfree queue

Question

all

I'm trying to use the boost library's lock free queue data structure.

#include <boost/thread/thread.hpp>
#include <boost/lockfree/queue.hpp>

However, I found out that these data structure do not support methods to get the number of current entries that these are containing (http://www.boost.org/doc/libs/1_53_0/doc/html/boost/lockfree/queue.html).

What I want is something similar to std::queue::size (http://en.cppreference.com/w/cpp/container/queue/size).

Thanks a lot for your help in advance!

Answer 1

If you just want to track high/low water marks, have an atomic counter that you increment when you enqueue, and decrement when you dequeue.

You can periodically sample that counter to do any tuning/statistical analysis that you might need.

The queue itself doesn't supply this operation, because you only pay for what you need.