// Copyright (C) 2013 Vicente Botet // // Distributed under the Boost Software License, Version 1.0. (See accompanying // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) // futtest.cpp #include #define BOOST_THREAD_VERSION 4 #include #include #include #include #include #include typedef boost::shared_ptr< boost::promise > IntPromise; void foo(IntPromise p) { std::cout << "foo" << std::endl; p->set_value(123); // This line locks the future's mutex, then calls the continuation with the mutex already locked. } void bar(boost::future fooResult) { try { std::cout << "bar" << std::endl; int i = fooResult.get(); // Code hangs on this line (Due to future already being locked by the set_value call) std::cout << "i: " << i << std::endl; } catch(...) { std::cout << __FILE__ << ":" << __LINE__ << std::endl; } } int main() { std::cout << __FILE__ << ":" << __LINE__ << std::endl; try { IntPromise p(new boost::promise()); boost::thread t(boost::bind(foo, p)); boost::future f1 = p->get_future(); f1.then(boost::launch::deferred, &bar); t.join(); } catch(...) { return 1; } std::cout << __FILE__ << ":" << __LINE__ << std::endl; try { IntPromise p(new boost::promise()); boost::thread t(boost::bind(foo, p)); boost::future f1 = p->get_future(); f1.then(boost::launch::async, &bar); t.join(); } catch(...) { return 2; } std::cout << __FILE__ << ":" << __LINE__ << std::endl; }