Question

I’m just starting out with C++ and am learning how to use QT creator as the IDE so I suspect this might be really easy but I might be missing something. I installed apollo MQ and installed the apache CMS(C++ messaging service) so I can interact with the server in C++. The problem is, I have no clue what I’m doing 🙂 (yet), and am not sure why I’m getting the above error when using the examples.

I am pretty sure the examples are good because they are included in the source’s example folder so it leads me to suspect that the configuration of the project is not correct(as its the only ting I really have an influence on).

Here’s the .pro file:

TEMPLATE = app
CONFIG += console
CONFIG -= qt

SOURCES += main.cpp

INCLUDEPATH += /usr/local/include/activemq-cpp-3.4.2/
INCLUDEPATH += /opt/local/lib/

Here is the folder contents where I’m pointing to(the files I want are all within the subdirectories there):

drwxr-xr-x  13 root  admin   442 May 11 19:09 activemq
drwxr-xr-x  48 root  admin  1632 May 11 19:09 cms
drwxr-xr-x   9 root  admin   306 May 11 19:09 decaf

Here’s the error I get:

20:54:22: Running build steps for project stackexchangeexample...
20:54:22: Configuration unchanged, skipping qmake step.
20:54:22: Starting: "/usr/bin/make" -w
make: Entering directory `/Users/lostsoul/Dropbox/qt_cuda/stackexchangeexample-build-desktop-Desktop_Qt_4_8_1_for_GCC__Qt_SDK__Debug'
/Users/lostsoul/QtSDK/Desktop/Qt/4.8.1/gcc/bin/qmake -spec ../../../QtSDK/Desktop/Qt/4.8.1/gcc/mkspecs/macx-g++ CONFIG+=declarative_debug -o Makefile ../stackexchangeexample/stackexchangeexample.pro
make: Leaving directory `/Users/lostsoul/Dropbox/qt_cuda/stackexchangeexample-build-desktop-Desktop_Qt_4_8_1_for_GCC__Qt_SDK__Debug'
make: Entering directory `/Users/lostsoul/Dropbox/qt_cuda/stackexchangeexample-build-desktop-Desktop_Qt_4_8_1_for_GCC__Qt_SDK__Debug'
g++ -headerpad_max_install_names -arch x86_64 -Xarch_x86_64 -mmacosx-version-min=10.5 -o stackexchangeexample.app/Contents/MacOS/stackexchangeexample main.o      
Undefined symbols for architecture x86_64:
  "activemq::library::ActiveMQCPP::initializeLibrary()", referenced from:
      _main in main.o
  "activemq::library::ActiveMQCPP::shutdownLibrary()", referenced from:
      _main in main.o
  "activemq::core::ActiveMQConnectionFactory::ActiveMQConnectionFactory(std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)", referenced from:
      SimpleProducer::run()      in main.o
  "cms::CMSException::CMSException(cms::CMSException const&)", referenced from:
      SimpleProducer::run()      in main.o
  "typeinfo for cms::CMSException", referenced from:
      GCC_except_table15 in main.o
      GCC_except_table16 in main.o
      SimpleProducer::run()      in main.o
  "cms::CMSException::~CMSException()", referenced from:
      SimpleProducer::run()      in main.o
  "decaf::lang::Thread::getId()", referenced from:
      SimpleProducer::run()      in main.o
  "decaf::lang::Long::toString(long long)", referenced from:
      SimpleProducer::run()      in main.o
ld: symbol(s) not found for architecture x86_64
collect2: ld returned 1 exit status
make: *** [stackexchangeexample.app/Contents/MacOS/stackexchangeexample] Error 1
make: Leaving directory `/Users/lostsoul/Dropbox/qt_cuda/stackexchangeexample-build-desktop-Desktop_Qt_4_8_1_for_GCC__Qt_SDK__Debug'
20:54:22: The process "/usr/bin/make" exited with code 2.
Error while building project stackexchangeexample (target: Desktop)
When executing build step 'Make'

and if it helps, here’s the code I run(it may not be useful to anyone for helping because you need to install a bunch of stuff to get it work, but just in case it helps):

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <decaf/lang/Thread.h>
#include <decaf/lang/Runnable.h>
#include <decaf/util/concurrent/CountDownLatch.h>
#include <decaf/lang/Long.h>
#include <decaf/util/Date.h>
#include <activemq/core/ActiveMQConnectionFactory.h>
#include <activemq/util/Config.h>
#include <activemq/library/ActiveMQCPP.h>
#include <cms/Connection.h>
#include <cms/Session.h>
#include <cms/TextMessage.h>
#include <cms/BytesMessage.h>
#include <cms/MapMessage.h>
#include <cms/ExceptionListener.h>
#include <cms/MessageListener.h>
#include <stdlib.h>
#include <stdio.h>
#include <iostream>
#include <memory>

using namespace activemq;
using namespace activemq::core;
using namespace decaf;
using namespace decaf::lang;
using namespace decaf::util;
using namespace decaf::util::concurrent;
using namespace cms;
using namespace std;

////////////////////////////////////////////////////////////////////////////////
class SimpleProducer : public Runnable {
private:

    Connection* connection;
    Session* session;
    Destination* destination;
    MessageProducer* producer;
    bool useTopic;
    bool clientAck;
    unsigned int numMessages;
    std::string brokerURI;
    std::string destURI;

private:

    SimpleProducer( const SimpleProducer& );
    SimpleProducer& operator= ( const SimpleProducer& );

public:

    SimpleProducer( const std::string& brokerURI, unsigned int numMessages,
                    const std::string& destURI, bool useTopic = false, bool clientAck = false ) :
        connection(NULL),
        session(NULL),
        destination(NULL),
        producer(NULL),
        useTopic(useTopic),
        clientAck(clientAck),
        numMessages(numMessages),
        brokerURI(brokerURI),
        destURI(destURI) {
    }

    virtual ~SimpleProducer(){
        cleanup();
    }

    void close() {
        this->cleanup();
    }

    virtual void run() {
        try {

            // Create a ConnectionFactory
            auto_ptr<ActiveMQConnectionFactory> connectionFactory(
                new ActiveMQConnectionFactory( brokerURI ) );

            // Create a Connection
            try{
                connection = connectionFactory->createConnection();
                connection->start();
            } catch( CMSException& e ) {
                e.printStackTrace();
                throw e;
            }

            // Create a Session
            if( clientAck ) {
                session = connection->createSession( Session::CLIENT_ACKNOWLEDGE );
            } else {
                session = connection->createSession( Session::AUTO_ACKNOWLEDGE );
            }

            // Create the destination (Topic or Queue)
            if( useTopic ) {
                destination = session->createTopic( destURI );
            } else {
                destination = session->createQueue( destURI );
            }

            // Create a MessageProducer from the Session to the Topic or Queue
            producer = session->createProducer( destination );
            producer->setDeliveryMode( DeliveryMode::NON_PERSISTENT );

            // Create the Thread Id String
            string threadIdStr = Long::toString( Thread::getId() );

            // Create a messages
            string text = (string)"Hello world! from thread " + threadIdStr;

            for( unsigned int ix=0; ix<numMessages; ++ix ){
                TextMessage* message = session->createTextMessage( text );

                message->setIntProperty( "Integer", ix );

                // Tell the producer to send the message
                printf( "Sent message #%d from thread %s\n", ix+1, threadIdStr.c_str() );
                producer->send( message );

                delete message;
            }

        }catch ( CMSException& e ) {
            e.printStackTrace();
        }
    }

private:

    void cleanup(){

        // Destroy resources.
        try{
            if( destination != NULL ) delete destination;
        }catch ( CMSException& e ) { e.printStackTrace(); }
        destination = NULL;

        try{
            if( producer != NULL ) delete producer;
        }catch ( CMSException& e ) { e.printStackTrace(); }
        producer = NULL;

        // Close open resources.
        try{
            if( session != NULL ) session->close();
            if( connection != NULL ) connection->close();
        }catch ( CMSException& e ) { e.printStackTrace(); }

        try{
            if( session != NULL ) delete session;
        }catch ( CMSException& e ) { e.printStackTrace(); }
        session = NULL;

        try{
            if( connection != NULL ) delete connection;
        }catch ( CMSException& e ) { e.printStackTrace(); }
        connection = NULL;
    }
};

////////////////////////////////////////////////////////////////////////////////
int main(int argc AMQCPP_UNUSED, char* argv[] AMQCPP_UNUSED) {

    activemq::library::ActiveMQCPP::initializeLibrary();

    std::cout << "=====================================================\n";
    std::cout << "Starting the example:" << std::endl;
    std::cout << "-----------------------------------------------------\n";

    // Set the URI to point to the IPAddress of your broker.
    // add any optional params to the url to enable things like
    // tightMarshalling or tcp logging etc.  See the CMS web site for
    // a full list of configuration options.
    //
    //  http://activemq.apache.org/cms/
    //
    // Wire Format Options:
    // =====================
    // Use either stomp or openwire, the default ports are different for each
    //
    // Examples:
    //    tcp://127.0.0.1:61616                      default to openwire
    //    tcp://127.0.0.1:61616?wireFormat=openwire  same as above
    //    tcp://127.0.0.1:61613?wireFormat=stomp     use stomp instead
    //
    std::string brokerURI =
        "failover://(tcp://127.0.0.1:61616"
//        "?wireFormat=openwire"
//        "&connection.useAsyncSend=true"
//        "&transport.commandTracingEnabled=true"
//        "&transport.tcpTracingEnabled=true"
//        "&wireFormat.tightEncodingEnabled=true"
        ")";

    //============================================================
    // Total number of messages for this producer to send.
    //============================================================
    unsigned int numMessages = 2000;

    //============================================================
    // This is the Destination Name and URI options.  Use this to
    // customize where the Producer produces, to have the producer
    // use a topic or queue set the 'useTopics' flag.
    //============================================================
    std::string destURI = "TEST.FOO";

    //============================================================
    // set to true to use topics instead of queues
    // Note in the code above that this causes createTopic or
    // createQueue to be used in the producer.
    //============================================================
    bool useTopics = false;

    // Create the producer and run it.
    SimpleProducer producer( brokerURI, numMessages, destURI, useTopics );

    // Publish the given number of Messages
    producer.run();

    // Before exiting we ensure that all CMS resources are closed.
    producer.close();

    std::cout << "-----------------------------------------------------\n";
    std::cout << "Finished with the example." << std::endl;
    std::cout << "=====================================================\n";

    activemq::library::ActiveMQCPP::shutdownLibrary();
}

I just created a empty c++ project, modified the .pro file to include a path to the libraries and then copy/pasted the code into main.cpp. Any idea what causes this? and how I can prevent it?

Answer 1

It looks like you’ve forgotten the library paths; you define INCLUDEPATH with new values but don’t add a corresponding LIBPATH or LIBRARYPATH or whatever the equivalent variable for libraries is named. Won’t you also need the corresponding -l library parameters for the specific libraries?