I have a quick question regarding connecting a bound member function. In the doc_view example application signals are defined as requiring a function taking a bool and returning nothing. class Document { public: typedef boost::signal< void (bool) > signal_t; // ... void append(const char* s) { m_text += s; m_sig(true); } // ... }; The View abstract base class requires concrete bases to provide a concrete implementation of the refresh() member function matching the slot signature required. class View { public: virtual void refresh(bool) const = 0; // ... }; Here's my problem. If I change the signal to take no args using the preferred or portable syntax I get compilation errors: class Document { public: typedef boost::signal< void () > signal_t; // ... void append(const char* s) { m_text += s; m_sig(true); } // ... }; class View { public: virtual void refresh() const = 0; // ... }; Compilation output (msvc-7.1): Compiling... SignalTest.cpp c:\Boost\include\boost-1_33_1\boost\bind.hpp(63) : error C2825: 'F::result_type': cannot form a qualified name c:\Boost\include\boost-1_33_1\boost\bind\bind_template.hpp(15) : see reference to class template instantiation 'boost::_bi::result_traits<R,F>' being compiled with [ R=boost::_bi::unspecified, F=void (__thiscall View::* )(void) const ] c:\development\SignalTest\SignalTest.cpp(49) : see reference to class template instantiation 'boost::_bi::bind_t<R,F,L>' being compiled with [ R=boost::_bi::unspecified, F=void (__thiscall View::* )(void) const, L=boost::_bi::list2<boost::_bi::list_av_2<View *,boost::arg<1>>::B1,boost::_bi::list_av_2<View *,boost::arg<1>>::B2> ] c:\Boost\include\boost-1_33_1\boost\bind.hpp(63) : error C2039: 'result_type' : is not a member of 'operator``global namespace''' c:\Boost\include\boost-1_33_1\boost\bind.hpp(63) : error C2146: syntax error : missing ';' before identifier 'type' c:\Boost\include\boost-1_33_1\boost\bind.hpp(63) : error C2955: 'boost::_bi::type' : use of class template requires template argument list c:\Boost\include\boost-1_33_1\boost\bind.hpp(112) : see declaration of 'boost::_bi::type' c:\Boost\include\boost-1_33_1\boost\bind.hpp(63) : fatal error C1903: unable to recover from previous error(s); stopping compilation Observed with boost_1_33_1 release on cygwin/gcc-3.4.4 and msvc-7.1 platforms. Any ideas? Many thanks in advance, -allen