Hello Andreas, Thanks for the help. I have eventually managed! In short I... - defined BOOST_ASIO_DISABLE_THREADS both while building Boost, and in the application which used it - implemented the atomic primitives using code from the gcc headers All working now! thanks, Jayne. On Fri 17/02/12 12:37 , "Andreas Wehrmann" a.wehrmann@centersystems.com sent: Alright, I looked into how I did when I faced the problem (my previous reply was a fast shot). I put the following #defines in the user config header (boost/config/user.hpp): #define BOOST_ASIO_DISABLE_FENCED_BLOCK #define BOOST_SP_USE_SPINLOCK This did the trick for me. From what I recall, the problem lies with shared_ptr since the implementation tries to use gcc builtins for the locking mechanism it needs for refcounting but which are not implemented on every platform (in my case it was Coldfire/m68k). Regards -- Dipl.-Ing. (FH) Andreas Wehrmann Software Development -------------------------------------------------------------- Center Communication Systems GmbH A-1210 Wien, Ignaz-Köck-Straße 19 Sitz in Wien FN 796 88p, Firmenbuchgericht Wien http://www.centersystems.com [1]">www.centersystems.com Tel.: +43 (0) 190 199 - 3616 Mobile: +43 (0) 664 884 75916 Fax: +43 (0) 190 199 - 2110 E-Mail: a.wehrmann@centersystems.com Links: ------ [1] http://www.centersystems.com