Hi: I am trying to use boost threads with condition variables on hpux with aCC compiler. The compiler has incomplete support of C++11 standard. It does not have <chrono> or <thread> headers. I get the following error message when compiling a program which is using condition variables: "/usr/local/include/boost/thread/pthread/thread_data.hpp", line 344: error #2135: namespace "boost::chrono" has no member "steady_clock" void sleep_until(const chrono::time_point<chrono::steady_clock, Duration>& t) ^ The c++ code is { while (bufferIsEmpty[bufferPairNo]) { boost::unique_lock<boost::mutex> lock (bufferIsEmptyMutex[bufferPairNo]); =>> zb_bufferIsEmptyCondVar[bufferPairNo].wait_for (lock, boost::chrono::microseconds (100)); } } The version of boost I am using is 1.69.0. I build boost with: ./bjam -a -j6 install --build-dir=build address-model=64 variant=release link=static \ threading=multi runtime-link=static \ define=BOOST_THREAD_DONT_USE_CHRONO \ --with-date_time --with-filesystem \ --with-system --with-thread When I look at the boost header file, I see this: boost/thread/pthread/ thread_data.hpp #ifdef BOOST_THREAD_USES_CHRONO template <class Rep, class Period> void sleep_for(const chrono::duration<Rep, Period>& d) { hidden::sleep_for_internal(detail::platform_duration(d)); } template <class Duration> line 344 >> void sleep_until(const chrono::time_point<chrono::steady_clock, Duration>& t) { sleep_for(t - chrono::steady_clock::now()); } It appears that the define=BOOST_THREAD_DONT_USE_CHRONO, had no affect. Have I built this correctly, or is there another problem? I would greatly appreciate any help on this. Best regards, John John Parke Alebra Technologies Inc. PO Box 120390 New Brighton, MN  55112 770-425-1810