When running the simple program listed below, the scoped_read_lock appears to never acquire a read lock on the mutex and, as a result, the program never finishes. In looking through the documentation, I don't think there is anything additional I need to do and was a bit surprised that this didn't work. Here is the code: boost::read_write_mutex m(static_cast(alternating_many_reads)); std::cout << "Before\n"; { boost::read_write_mutex::scoped_write_lock l(m); } std::cout << "Middle\n"; { boost::read_write_mutex::scoped_read_lock l(m); } std::cout << "After\n"; And some more details: - test_read_write_mutex.cpp completed without problems - writer_priority and reader_priority completed without problems. Only alternating_many_reads and alternating_single_read seem to have problems. - Windows XP SP2 - Microsoft Visual Studio 2003 - I am compiling with the Multithreaded DLL version of the CRT, so boost_thread-vc71-mt-gd-1_32.lib is being used Thanks for your help! David Brownell