Hi, This has probably been asked before. I cant find doco giving detail. So excuse me if this is old topic. I am involved with GPL project that uses boost::threads. I have a problem understanding implementation and what threadmon.dll is for. I see that the code is attempting to manage tss stuff. How is the tss stuff managed when lib is a static link under win32? Is it correct that if I wish to static link that I need this other threadmon.dll as well. Has it been suggested that structured exceptions can perform the same function on win32 with a finally() handler from within thread_proxy? This is a gurantee of invocation. The cleanup attempt could though win32 doco states cleanup is guranteed, though couldnt a lib global could easily handle main thread cleanup? Regards Martin Johnson