Hi, In search of a std:atomic<T> implementation, I decided to give boost.atomic library a try. My initial investigation found it worked fine under linux. However it does not work on Windows. Here is a little test program to demonstrate: #include <iostream> #include <boost/atomic.hpp> #include <boost/lockfree/detail/tagged_ptr.hpp> #include <boost/lockfree/detail/freelist.hpp> int main() { boost::lockfree::caching_freelist<int> pool(3); int* pInt1 = pool.allocate(); *pInt1 = 1; int* pInt2 = pool.allocate(); *pInt2 = 2; int* pInt3 = pool.allocate(); *pInt3 = 3; pool.deallocate(pInt1); pool.deallocate(pInt2); pool.deallocate(pInt3); int* pInt4 = pool.allocate(); int* pInt5 = pool.allocate(); int* pInt6 = pool.allocate(); } The test uses boost.lockfree library, which you can download from http://tim.klingt.org/git?p=boost_lockfree.git If you set a break point, say in fallback.hpp, you will see that on Windows it falls back to spinlock. Can somebody please suggest how to fix this? I suspect the issue has something to do with intptr_t type. I looked into the code but quickly started to have headache. Atomic library uses template metaprogramming and is not easy to understand. -Anqing