I have a class, where I want callers to be able to register/deregister signals/slots. They will pass in a function pointer, and we'll hook it up to the signal, and manage the connection object. Part of the management, is I need to map the function pointer to the actual connection object. This is where the trouble comes in. Since a boost::function doesn't have an operator <, the simplest way is to just map it to an unsigned long long, and store the raw address of the underlying function. So, my connect function: typedef VSSP (*TargetType) ( std::string, EncodingEnum); typedef boost::function < VSSP ( std::string, EncodingEnum) > CreateTypeFunc; bool ElementBase::connectCreateTypeSignal(const CreateTypeFunc& slot) { LOG4CXX_DEBUG(logger_, "connectCreateTypeSignal in"); bool retValue = false; unsigned long long slotAddr = (unsigned long long)slot.target< TargetType >(); LOG4CXX_DEBUG(logger_, "*** slotAddr = " + (boost::format("%08X") % slotAddr).str()); <snip> } One of my checks, is to ensure that you don't connect the same thing multiple times. So, I have a test case that does this, and expects it to bomb out: VSSP getTypeSlot(std::string fqn, EncodingEnum encoding) { <snip> return VSSP; } BOOST_FIXTURE_TEST_CASE(ElementBase_connectCreateType, ElementBaseTestFixture) { BOOST_CHECK(true == ebp->connectCreateTypeSignal(getTypeSlot)); BOOST_CHECK(false == ebp->connectCreateTypeSignal(getTypeSlot)); } My debug printouts, are shoing unexpected behavior. The address that I am getting from target is different every time it is called, even though I'm calling with the same function (getTypeSlot). I would expect this if I was getting the address of the function object, because I'm creating one implicitly through the call, but not dereferencing via target(), unless I'm misunderstanding what target() does. I just need the stupid address of the function passed in. Help!! TIA --dw