Hi, The Boost.Thread documentation points out that boost::thread is non- copyable but then goes on to provide rational for why it should be possible to return by value from make_thread_return_local(). Intel-11.1 on Darwin is a recent compiler that will not compile this code. [ from libs/thread/test/test_thread_return_local.cpp ] boost::thread make_thread_return_local(boost::thread::id* the_id) { boost::thread t(do_nothing,the_id); return t; } The same error message is generated in both debug and release builds on Darwin (though strangely it doesn't appear to be an error with Intel 11.1 on Linux). "/opt/intel/Compiler/11.1/067/bin/intel64/icpc" -xc++ -w1 -O0 -g - inline-level=0 -vec-report0 -DBOOST_ALL_NO_LIB=1 - DBOOST_TEST_NO_AUTO_LINK=1 -DBOOST_THREAD_POSIX - DBOOST_THREAD_USE_LIB=1 -I".." -c -o "/Volumes/Scratch/kbelco/boost/ results/boost/bin.v2/libs/thread/test/ test_thread_return_local_lib.test/intel-darwin-11.1/debug/threading- multi/test_thread_return_local.o" "../libs/thread/test/ test_thread_return_local.cpp" ../libs/thread/test/test_thread_return_local.cpp(16): error #373: "boost::thread::thread(boost::thread &)" (declared at line 111 of "../ boost/thread/detail/thread.hpp") is inaccessible return t; ^ Any ideas how to work around this failure? Thanks. -- Noel