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Problem compiling C++


I have been using Ice with Python for some time with good results. I now need a C++ node. I'm no doubt doing something stupid but would appreciate it if someone could put me straight.

I'm using Eclipse on Ubuntu 8.04. This is a very simple test node with a test interface just so I can get some comms going from my Python node to C++ node.

Here is the Ice def:

module AcornDisplays
    interface Displays
        void data(string display);


and here is the code.
#include <Ice/Ice.h>
#include <IceStorm/IceStorm.h>
#include "displays.h"

using namespace std;
using namespace AcornDisplays;

class DisplaysI : virtual public Displays {

	virtual void data(const string& s, const Ice::Current&);

void DisplaysI::data(const string& s, const Ice::Current&) {
	cout << "Got some data!";

int main(int argc, char* argv[])
	int status = 0;

	Ice::CommunicatorPtr ic;
	IceStorm::TopicManagerPrx topicManager;
	Ice::ObjectPrx proxy;
	Ice::ObjectAdapterPtr adapter;
	IceStorm::TopicPrx topic;
	try {
		ic = Ice::initialize(argc, argv);
		Ice::ObjectPrx obj = ic->propertyToProxy("TopicManager.Proxy");
		topicManager = IceStorm::TopicManagerPrx::checkedCast(obj);
		adapter = ic->createObjectAdapter("Display.Subscriber");
		DisplaysPtr display = new DisplaysI;
		proxy = adapter->addWithUUID(display)->ice_oneway();
	} catch (const Ice::Exception& e) {
		cerr << e << endl;
		status = 1;

	try {
		topic = topicManager->retrieve("Display");
		IceStorm::QoS qos;
		topic->subscribeAndGetPublisher(qos, proxy);
	catch (const IceStorm::NoSuchTopic&) {
		cout << "Error! No topic found!";

	try {
	} catch (const Ice::Exception& e) {
		cerr << e << endl;
		status = 1;


	return status;

I am linking with Ice, IceUtil and IceStorm. I am getting the following link errors which I don't understand.
/home/bob/dev/projects/acorn-sdr/ice/displays.h undefined reference to `vtable for AcornDisplays::Displays'	displays
/home/bob/dev/projects/acorn-sdr/ice/displays.h undefined reference to `VTT for AcornDisplays::Displays'	displays
/opt/Ice-3.3.0/include/Ice/Handle.h undefined reference to `IceInternal::upCast(AcornDisplays::Displays*)'	displays
/opt/Ice-3.3.0/include/Ice/Handle.h undefined reference to `IceInternal::upCast(AcornDisplays::Displays*)'	displays



  • dwayne
    dwayne St. John's, Newfoundland
    It sounds like you are not compiling the generated .cpp file (displays.cpp?) or just not linking with the resultant object file if you are compiling it.
  • Thanks for the prompt reply. As far as I can tell everything is compiled and linked. I tried it from the makefile rather than the IDE. I get a lot more errors so I have just given the first few.
    bob@bob-desktop:~/dev/projects/acorn-sdr/src/displays/Release$ make
    Building file: ../display_main.cpp
    Invoking: GCC C++ Compiler
    g++ -I/home/bob/dev/projects/acorn-sdr/src/displays -I/home/bob/dev/projects/acorn-sdr/ice -I/opt/Ice-3.3.0/include -O3 -Wall -c -fmessage-length=0 -MMD -MP -MF"display_main.d" -MT"display_main.d" -o"display_main.o" "../display_main.cpp"
    Finished building: ../display_main.cpp
    Building target: displays
    Invoking: GCC C++ Linker
    g++ -L/opt/Ice-3.3.0/lib -o"displays"  ./display_main.o   -lIce -lIceUtil -lIceStorm
    ./display_main.o: In function `main':
    display_main.cpp:(.text+0x425): undefined reference to `IceInternal::upCast(AcornDisplays::Displays*)'
    display_main.cpp:(.text+0x515): undefined reference to `IceInternal::upCast(AcornDisplays::Displays*)'
    display_main.cpp:(.text+0xb64): undefined reference to `IceInternal::upCast(AcornDisplays::Displays*)'
  • matthew
    matthew NL, Canada
    g++ -L/opt/Ice-3.3.0/lib -o"displays" ./display_main.o -lIce -lIceUtil -lIceStorm

    Surely display.o (or whatever the name of the translated slice file is) is missing from that list.
  • Of course it is. I was just blind and forgot about the auto-generated file. Sorry for the noise.