Probably already a known problem, but if one uses the signals library as a dll, the dll does not contain all exports (e.g. signal_base_impl::~signal_base_impl()). Tracking this down it looks like that the file 'signal_base.cpp' does not see that it has to create exported functions. This is due to the fact that 'BOOST_HAS_DECLSPEC' is not defined, which is defined a compiler specific header file ('visualc.hpp').

However another cpp file from signals, 'connection.cpp', does create exported function.

Thus as a work around I added '#include <boost/signals/detail/signals_common.hpp>' as first include in 'signal_base.cpp' (and also to the other cpp files of signals) and bjamed again.