Strange Unresolved External Symbol in C++/CLI - c++

Question

I have a LNK2001 error which I cannot solve!
My Solution is composed by a native project (DLL) and a managed one (DLL wrapper).
The native DLL works if is used with a native test application.
Now, the native code is the following (all defined into the namespace EuroSDK::Protocols) :
The EUROSDK_API is defined as __declspec(dllexport)
IMessageDispatcher.h
class EUROSDK_API IMessageDispatcher {
public:
IMessageDispatcher() : m_ProtocolAdapter(0) {};
virtual ~IMessageDispatcher() {};
virtual ERROR_CODE SendMessage(IMessage & msg) = 0;
virtual ERROR_CODE SendMessage(IMessage & msg, STRING destination) {
RAISE_AND_RETURN(EC_NOT_IMPLEMENTED);
};
virtual ERROR_CODE SendMessageSync(IMessage & msg) {
RAISE_AND_RETURN(EC_NOT_IMPLEMENTED);
};
virtual ERROR_CODE SendMessageSync(IMessage & msg, IMessage & ret_msg) {
RAISE_AND_RETURN(EC_NOT_IMPLEMENTED);
};
virtual ERROR_CODE SendMessageRaw(char* buff, UINT size) {
RAISE_AND_RETURN(EC_NOT_IMPLEMENTED);
};
ERROR_CODE SetProtocolAdapter(IProtocolAdapter * adapter) {
m_ProtocolAdapter = adapter;
return EC_NO_ERRORS;
}
protected:
IProtocolAdapter* m_ProtocolAdapter;
};
class EUROSDK_API INetMessageDispatcher : public IMessageDispatcher {
public:
virtual ERROR_CODE Init(STRING stationName,
STRING userName,
BOOL crypthData = FALSE) = 0;
virtual ERROR_CODE Connect(UINT portNumber,
STRING remoteIP,
UINT connectionTimeOut = 5000) = 0;
virtual ERROR_CODE Disconnect() = 0;
};
NetMessageDispatcher.h
class EUROSDK_API NetMessageDispatcher : public INetMessageDispatcher
{
...
ERROR_CODE SendMessage(IMessage & msg);
ERROR_CODE SendMessage(IMessage & msg, STRING destination);
...
};
NetMessageDispatcher.cpp
ERROR_CODE NetMessageDispatcher::SendMessage(IMessage & msg) {
... implementation ...
}
ERROR_CODE NetMessageDispatcher::SendMessage(IMessage & msg, STRING destination) {
... implementation ...
}
Now, into the managed wrapper I have:
NetMessageDispatcherNET.h
using namespace EurocSDK::Protocols;
namespace EuroSDKNET {
namespace Protocols {
class NetMessageDispatcherWrap;
public ref class NetMessageDispatcherNET {
public:
NetMessageDispatcherNET(EDispatcherType stationType,
MessageEventHandlerNET^ handler)
~NetMessageDispatcherNET() {};
// Implemented in the cpp file
virtual int SendMessage(IMessageNET^ msg);
virtual int SendMessage(IMessageNET^ msg, String^ destination);
private:
CAutoNativePtr<NetMessageDispatcherWrap> m_Dispatcher;
};
// Unmanaged Wrapper
private class NetMessageDispatcherWrap : public ISessionFactory,
public NetMessageDispatcher {
public:
~NetMessageDispatcherWrap() {}
NetMessageDispatcherWrap(MessageEventHandlerNET^ handler,
NetMessageDispatcherNET^ dispatcher,
IMessageFactory::Ptr messageFactory,
EuroSDKNET::Protocols::EDispatcherType stationType) :
NetMessageDispatcher(this,
messageFactory,
Logger::get("NetMessageDispatcher"),
(EuroSDK::Protocols::EDispatcherType)stationType),
m_handler(handler),
m_Dispatcher(dispatcher) {}
/// Creates an instance of a Session,
/// using the given message handler.
inline Session* createSession(const IMessageDispatcher* dispatcher) {
..... implementation ....
}
private:
gcroot<MessageEventHandlerNET^> m_handler;
gcroot<NetMessageDispatcherNET^> m_Dispatcher;
};
}
}
NetMessageDispatcherNET.cpp
NetMessageDispatcherNET::NetMessageDispatcherNET(EuroSDKNET::Protocols::EDispatcherType stationType,
MessageEventHandlerNET^ handler) {
m_Dispatcher = new NetMessageDispatcherWrap(handler,
this,
new EuroSDK::Protocols::PBMessageFactory(),
stationType);
}
NetMessageDispatcherNET::~NetMessageDispatcherNET() {}
int NetMessageDispatcherNET::SendMessage(IMessageNET^ msg) {
return 0;
}
int NetMessageDispatcherNET::SendMessage(IMessageNET^ msg, String^ destination) {
return 0;
}
Now, when I build the NET DLL I get:
1>NetMessageDispatcher.obj : warning LNK4248: unresolved typeref token (01000017) for 'boost.detail.win32._SECURITY_ATTRIBUTES'; image may not run
1>NetMessageDispatcherWrapper.obj : error LNK2001: unresolved external symbol "public: virtual enum E_ErrorCode __thiscall EuroSDK::Protocols::NetMessageDispatcher::SendMessage(class EuroSDK::Protocols::IMessage &,class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >)" (?SendMessage#NetMessageDispatcher#Protocols#EuroSDK##UAE?AW4E_ErrorCode##AAVIMessage#23#V?$basic_string#DU?$char_traits#D#std##V?$allocator#D#2##std###Z)
1>NetMessageDispatcherWrapper.obj : error LNK2001: unresolved external symbol "public: virtual enum E_ErrorCode __thiscall EuroSDK::Protocols::NetMessageDispatcher::SendMessage(class EuroSDK::Protocols::IMessage &)" (?SendMessage#NetMessageDispatcher#Protocols#EuroSDK##UAE?AW4E_ErrorCode##AAVIMessage#23##Z)
What could cause the problem?
Daniele.

Answer 1

Based on your new comments and your edit
in your IMessageDispatcher class you are defining
virtual ERROR_CODE SendMessage(IMessage & msg) = 0;
virtual ERROR_CODE SendMessage(IMessage & msg, STRING destination) {
RAISE_AND_RETURN(EC_NOT_IMPLEMENTED);
};
Now INetMessageDispatcher inherits those 2 functions from IMessageDispatcher which means they can be called on an INetMessageDispatcher instance after youi implement the pure virtual one.
Next, NetMessageDispatcher inherits those two functions from INetMessageDispatcher and that is a redefinition, so your solution is
1) either remove the redifinitions from the NetMessageDispatcher class, they are unnecessary
2) If you use C++ 11 you could use an override keyword
class EUROSDK_API NetMessageDispatcher : public INetMessageDispatcher
{
...
virtual ERROR_CODE SendMessage(IMessage & msg) override;
}