Hi, Testing my own wrapper on x86_64 bit linux exposed a seeming deadlock on constructing a read_write_lock with a *::write_locked initial state in the constructor... I've distilled it to the plain code below that exhibits the same failure. Using a read_lock state on the same works without deadlock (or safety is this case) as expected. Using a scoped_write_lock worked once but deadlocked mostly. A normal mutex and recursive mutex works as expected. I'm using 1.33. Is this a known bug or am I using the read_write stuff incorrectly? Regards, Matt. matthurd@acm.org ____________________________________ my test in question:... void synch_test_019() { static int global_count = 0; static boost::read_write_mutex doobie( boost::read_write_scheduling_policy::writer_priority ); long number_of_threads = 10; static long inner_loop = 1000; ZOMOJO_WORKER_THREAD_BEGIN( inner_loop ) { boost::read_write_mutex::scoped_read_write_lock lk(doobie, boost::read_write_lock_state::write_locked); global_count = global_count + 1; } ZOMOJO_WORKER_THREAD_END( number_of_threads ) BOOST_MESSAGE( "orderly progression = " << inner_loop * number_of_threads ); BOOST_MESSAGE( "concurrent progression from this run = " << global_count ); BOOST_CHECK_PREDICATE(std::equal_to<int>(), (global_count)( inner_loop * number_of_threads) ); } _________________________________________________ The helper macros _________________________________________________ #ifndef ZOMOJO_THREAD_TEST_HELPER_HPP_20050816 #define ZOMOJO_THREAD_TEST_HELPER_HPP_20050816 // A poor man's barrier helper to assist in unit test cases for parallel execution #define ZOMOJO_WORKER_THREAD_BEGIN( LoopIterations ) \ static boost::read_write_mutex m_arbitrary_( boost::read_write_scheduling_policy::writer_priority ); \ struct simple_function_arbitrary_ \ { \ static void do_work_arbitrary_() \ { \ boost::read_write_mutex::scoped_read_lock lk_arbitrary_(m_arbitrary_); \ for (int j_arbitrary_ = 0; j_arbitrary_ < (LoopIterations); j_arbitrary_++) \ { #define ZOMOJO_WORKER_THREAD_END( NumberOfThreads ) \ } \ } \ }; \ \ boost::thread_group pool_arbitrary_; \ \ { \ boost::read_write_mutex::scoped_write_lock lk(m_arbitrary_); \ for (int i_arbitrary_=0; i_arbitrary_ < NumberOfThreads; ++i_arbitrary_) \ { \ pool_arbitrary_.create_thread( simple_function_arbitrary_::do_work_arbitrary_ ); \ } \ } \ \ pool_arbitrary_.join_all(); #endif // ZOMOJO_THREAD_TEST_HELPER_HPP_20050816