I'm trying to create a shared library using Poco and I always seem to get:

ld: Undefined symbols:
__ZN5osmed20requestHandlerModuleC2Ev
__ZN5osmed20requestHandlerModuleD2Ev
__ZTIN5osmed20requestHandlerModuleE
/usr/bin/libtool: internal link edit command failed
make[2]: *** [libdummy.dylib] Error 1
make[1]: *** [CMakeFiles/dummy.dir/all] Error 2
make: *** [all] Error 2

but I'm not sure why, I've reduced my code below down to basically nothing and I still get the same results.  I'm using OS X 10.4


//////////////////// requestHandlerModule.h   ///////////////////////////
#ifndef _REQUEST_HANDLER_MODULE_
#define _REQUEST_HANDLER_MODULE_

namespace osmed {

class requestHandlerModule {
    public:
        requestHandlerModule();
        virtual ~requestHandlerModule();
};

}
#endif /* _REQUEST_HANDLER_MODULE_ */

//////////////////// dummyRequest.cpp  ///////////////////////////
#include "requestHandlerModule.h"
#include "Poco/ClassLibrary.h"

namespace osmed {

class dummyRequestHandler : public requestHandlerModule {
    public:
        dummyRequestHandler::dummyRequestHandler(){}
        dummyRequestHandler::~dummyRequestHandler(){}

};

}

using osmed::requestHandlerModule;
using osmed::dummyRequestHandler;
POCO_BEGIN_MANIFEST(requestHandlerModule)
    POCO_EXPORT_CLASS(dummyRequestHandler)
POCO_END_MANIFEST