William E. Kempf wrote:
Actually, we can, and do in the thread_dev branch. It means that the ID is of implementation defined type, but it's portable.
In the mean time I would probably do something like the following: (obviously it needs a bit of fleshing out) template<class T> class thread_map { class wrapper; public: typedef const wrapper* id; id create(const boost::function1<void, id> &f, const T& data) { boost::mutex::scoped_lock lock(m); threads.push_back(boost::shared_ptr<wrapper>(new wrapper(f))); return ids.insert(std::make_pair(threads.back().get(), data)).first->first; } T& operator[](id x) { boost::mutex::scoped_lock lock(m); std::map<id, T>::iterator i(ids.find(x)); if (i == ids.end()) throw std::out_of_range("Thread ID does not exist"); return i->second; } private: class wrapper : boost::noncopyable { boost::thread t; public: explicit wrapper(boost::function1<void, id> f) : t(boost::bind<void>(f, this)) {} }; boost::mutex m; std::map<id, T> ids; std::vector<boost::shared_ptr<wrapper> > threads; }; void mythread(thread_map<int>::id id) { /* do something */ } void f() { thread_map<int> threads; thread_map<int>::id id(threads.create(&mythread, 42)); DEBUG_ASSERT(threads[id] == 42); }