[signals] Compiler warnings with BOOST_ALL_DYN_LINK
Hello, I have a problem using Boost.Signals. With this test program: <code> // See the previous thread regarding // "[regex] Unresolved external symbols under VC7.1 w/ dynamic linking #define BOOST_ALL_DYN_LINK #include <boost/signals.hpp> int main(int argc, char* argv[]) { return 0; } </code> I get some compiler warnings under MSVC 7.1 / Boost 1.32. Is there something I can do about it? Here is the compiler output I get: c:\dev\Libraries\Boost\include\boost-1_32\boost\signals\connection.hpp(111) : warning C4251: 'boost::signals::connection::con' : class 'boost::shared_ptr<T>' needs to have dll-interface to be used by clients of class 'boost::signals::connection' with [ T=boost::signals::detail::basic_connection ] c:\dev\Libraries\Boost\include\boost-1_32\boost\signals\trackable.hpp(55) : warning C4251: 'boost::signals::trackable::connected_signals' : class 'std::list<_Ty>' needs to have dll-interface to be used by clients of class 'boost::signals::trackable' with [ _Ty=boost::signals::connection ] c:\dev\Libraries\Boost\include\boost-1_32\boost\signals\slot.hpp(51) : warning C4251: 'boost::signals::detail::slot_base::data' : class 'boost::shared_ptr<T>' needs to have dll-interface to be used by clients of class 'boost::signals::detail::slot_base' with [ T=boost::signals::detail::slot_base::data_t ] c:\dev\Libraries\Boost\include\boost-1_32\boost\signals\detail\named_slot_map.hpp(100) : warning C4251: 'boost::signals::detail::named_slot_map_iterator::impl_' : class 'boost::scoped_ptr<T>' needs to have dll-interface to be used by clients of class 'boost::signals::detail::named_slot_map_iterator' with [ T=boost::signals::detail::named_slot_map_iterator::impl ] c:\dev\Libraries\Boost\include\boost-1_32\boost\signals\detail\named_slot_map.hpp(129) : warning C4251: 'boost::signals::detail::named_slot_map::impl_' : class 'boost::scoped_ptr<T>' needs to have dll-interface to be used by clients of class 'boost::signals::detail::named_slot_map' with [ T=boost::signals::detail::named_slot_map::impl ] c:\dev\Libraries\Boost\include\boost-1_32\boost\signals\detail\signal_base.hpp(40) : warning C4251: 'boost::signals::detail::call_notification::impl' : class 'boost::shared_ptr<T>' needs to have dll-interface to be used by clients of class 'boost::signals::detail::call_notification' with [ T=boost::signals::detail::signal_base_impl ] c:\dev\Libraries\Boost\include\boost-1_32\boost\signals\detail\signal_base.hpp(114) : warning C4251: 'boost::signals::detail::signal_base_impl::combiner_' : class 'boost::any' needs to have dll-interface to be used by clients of class 'boost::signals::detail::signal_base_impl' c:\dev\Libraries\Boost\include\boost-1_32\boost\any.hpp(22) : see declaration of 'boost::any' c:\dev\Libraries\Boost\include\boost-1_32\boost\signals\detail\signal_base.hpp(120) : warning C4275: non dll-interface class 'boost::noncopyable_::noncopyable' used as base for dll-interface class 'boost::signals::detail::signal_base' c:\dev\Libraries\Boost\include\boost-1_32\boost\noncopyable.hpp(22) : see declaration of 'boost::noncopyable_::noncopyable' c:\dev\Libraries\Boost\include\boost-1_32\boost\signals\detail\signal_base.hpp(120) : see declaration of 'boost::signals::detail::signal_base' c:\dev\Libraries\Boost\include\boost-1_32\boost\signals\detail\signal_base.hpp(150) : warning C4251: 'boost::signals::detail::signal_base::impl' : class 'boost::shared_ptr<T>' needs to have dll-interface to be used by clients of class 'boost::signals::detail::signal_base' with [ T=boost::signals::detail::signal_base_impl ] Best, Klaus -- Klaus Nowikow DECOMSYS - Dependable Computer Systems Development Engineer Stumpergasse 48/14, A-1060 Wien, Austria Phone: +43 1 59983-31 Fax: +43 1 59983-731 http://www.decomsys.com
----- Original Message ----- From: "Klaus Nowikow" <nowikow@decomsys.com> To: <boost-users@lists.boost.org> Sent: Thursday, March 24, 2005 11:23 AM Subject: [Boost-users] [signals] Compiler warnings with BOOST_ALL_DYN_LINK
Hello,
I have a problem using Boost.Signals. With this test program:
<code> // See the previous thread regarding // "[regex] Unresolved external symbols under VC7.1 w/ dynamic linking #define BOOST_ALL_DYN_LINK #include <boost/signals.hpp>
int main(int argc, char* argv[]) { return 0; } </code>
I get some compiler warnings under MSVC 7.1 / Boost 1.32. Is there something I can do about it?
Here is the compiler output I get:
c:\dev\Libraries\Boost\include\boost-1_32\boost\signals\connection.hpp(111) : warning C4251: 'boost::signals::connection::con' : class 'boost::shared_ptr<T>' needs to have dll-interface to be used by clients of class 'boost::signals::connection'
There is not a great deal you can with this warning other than turn it off. #pragma warning (disable: 4251) ---- ------ #pragma warning (default: 4251) We do this often. The alternative is to explicitly instantiate your template code and do the usuall things with __declspec(dllexport) etc.. which turn into a nightmare to maintain and a serious code bloat as well as exported dll entries and import libraies. I try to keep the warning switches as close to the offending code as possible for documentation reasons, even inside a class declaration: Here is an example: class MYPROJECT_EXPORT MyClass { private: #pragma warning (disable: 4251) std::list<OtherClass*> Talkers; #pragma warning (default: 4251) ..... }; (NB: beware of warnings that make it into precompiled headers) regards, Conrad Weyns
with [ T=boost::signals::detail::basic_connection ] c:\dev\Libraries\Boost\include\boost-1_32\boost\signals\trackable.hpp(55) : warning C4251: 'boost::signals::trackable::connected_signals' : class 'std::list<_Ty>' needs to have dll-interface to be used by clients of class 'boost::signals::trackable' with [ _Ty=boost::signals::connection ] c:\dev\Libraries\Boost\include\boost-1_32\boost\signals\slot.hpp(51) : warning C4251: 'boost::signals::detail::slot_base::data' : class 'boost::shared_ptr<T>' needs to have dll-interface to be used by clients of class 'boost::signals::detail::slot_base' with [ T=boost::signals::detail::slot_base::data_t ] c:\dev\Libraries\Boost\include\boost-1_32\boost\signals\detail\named_slot_map.hpp(100) : warning C4251: 'boost::signals::detail::named_slot_map_iterator::impl_' : class 'boost::scoped_ptr<T>' needs to have dll-interface to be used by clients of class 'boost::signals::detail::named_slot_map_iterator' with [ T=boost::signals::detail::named_slot_map_iterator::impl ] c:\dev\Libraries\Boost\include\boost-1_32\boost\signals\detail\named_slot_map.hpp(129) : warning C4251: 'boost::signals::detail::named_slot_map::impl_' : class 'boost::scoped_ptr<T>' needs to have dll-interface to be used by clients of class 'boost::signals::detail::named_slot_map' with [ T=boost::signals::detail::named_slot_map::impl ] c:\dev\Libraries\Boost\include\boost-1_32\boost\signals\detail\signal_base.hpp(40) : warning C4251: 'boost::signals::detail::call_notification::impl' : class 'boost::shared_ptr<T>' needs to have dll-interface to be used by clients of class 'boost::signals::detail::call_notification' with [ T=boost::signals::detail::signal_base_impl ] c:\dev\Libraries\Boost\include\boost-1_32\boost\signals\detail\signal_base.hpp(114) : warning C4251: 'boost::signals::detail::signal_base_impl::combiner_' : class 'boost::any' needs to have dll-interface to be used by clients of class 'boost::signals::detail::signal_base_impl' c:\dev\Libraries\Boost\include\boost-1_32\boost\any.hpp(22) : see declaration of 'boost::any' c:\dev\Libraries\Boost\include\boost-1_32\boost\signals\detail\signal_base.hpp(120) : warning C4275: non dll-interface class 'boost::noncopyable_::noncopyable' used as base for dll-interface class 'boost::signals::detail::signal_base' c:\dev\Libraries\Boost\include\boost-1_32\boost\noncopyable.hpp(22) : see declaration of 'boost::noncopyable_::noncopyable'
c:\dev\Libraries\Boost\include\boost-1_32\boost\signals\detail\signal_base.hpp(120) : see declaration of 'boost::signals::detail::signal_base' c:\dev\Libraries\Boost\include\boost-1_32\boost\signals\detail\signal_base.hpp(150) : warning C4251: 'boost::signals::detail::signal_base::impl' : class 'boost::shared_ptr<T>' needs to have dll-interface to be used by clients of class 'boost::signals::detail::signal_base' with [ T=boost::signals::detail::signal_base_impl ]
Best,
Klaus
-- Klaus Nowikow DECOMSYS - Dependable Computer Systems Development Engineer Stumpergasse 48/14, A-1060 Wien, Austria Phone: +43 1 59983-31 Fax: +43 1 59983-731 http://www.decomsys.com
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