Hello, I have to use Boost with VC++5 even if it this compiler isn't supposed to be supported. That's because we have a quite huge software developped with VC++5 and we don't have enough time to re-pass the entire test book (several hundreds of pages with 10 pixel-sized fonts). By disabling the #error directive in the compiler configuration hpp file, I'm surprised to see all seem to work fine. So my 1st question is : - Why such a #error directive ? Moreover, I have a POSIX.1c compliant threads implementation under WIN32 (PThreads Win32 downloaded from the RedHat site) that I want to use. So my 2nd question is : - What are the right minimum set of #define's I have to put (_REENTRANT, _POSIX_THREADS, BOOST_DISABLE_WIN32, etc.) ? Thank you very, very, much in advance, Best regards, Regis.