I would like to use boost::thread (static library) in a DLL project that also includes some managed C++. Thus I am attempting to disable the automatic TLS cleanup, since the TLS callbacks it uses are not compatible with managed code. I have found references to two methods of doing this: 1) Define tss_cleanup_implemented() to prevent the automatic cleanup code from being linked in: http://lists.boost.org/Archives/boost/2007/11/130440.php 2) Build the thread library without tss_pe.cpp: http://boost.2283326.n4.nabble.com/Using-new-threads-link-issues-td2637128.h... My questions are: 1) Are these two methods functionally equivalent? 2) How exactly does defining tss_cleanup_implemented prevent the cleanup code from being linked in? Is the idea that if a definition exists locally the linker won't go looking for one in the library and thus won't link the cleanup code either? When I define extern "C" void tss_cleanup_implemented(void){} within my project in the global namespace, I get linker errors about multiply defined symbols (LNK2005, LNK1169) -- are there other linker settings I need to change in order for it to work? I'm using Visual Studio 2008. Finally, I just want to confirm that once I've disabled the automatic cleanup, I only need to call on_thread_exit() from threads launched through the native API that use boost::thread functionality like thread_specific_ptr. If the application only launches threads through boost, I just need to call on_process_enter/exit in main. Correct? Thanks, Sarah