[Solved]Issues with OpenCV - Error message: symbol(s) not found for architecture x86_64

[joned]

After 4 hours of struggling with linking problems with openCV I finally made it to locate them.
When I try testing it with something simple as showing a simple image, i get this error message which doesn't make sence. I know it has to do with openCV, because something as simple as "hello world" runs easily.

my .pro looks like this
@#-------------------------------------------------

Project created by QtCreator 2015-01-23T19:58:31

#-------------------------------------------------

QT += core gui

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

TARGET = TEST
TEMPLATE = app

INCLUDEPATH += /usr/local/include

HEADERS += mainwindow.h

LIBS += -L/usr/local/lib
-lopencv_core
-lopencv_imgcodecs
-lopencv_highgui

SOURCES += main.cpp
mainwindow.cpp

FORMS += mainwindow.ui
@

mainwindow.h
@#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
Q_OBJECT

public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();

private:
Ui::MainWindow *ui;
};

#endif // MAINWINDOW_H
@
main.cpp
@#include "mainwindow.h"
#include <QApplication>
#include <QString>
#include <iostream>
#include <opencv/cv.h>
#include <opencv/highgui.h>

int main(int argc, char argv[])
{
QApplication a(argc, argv);
MainWindow w;
w.show();
std::cout << "hello world - lalala" << std::endl;
IplImage img = 0;
img = cvLoadImage("/users/horse.jpg");
cvNamedWindow("Exmaple1", CV_WINDOW_AUTOSIZE);
cvShowImage("Exmaple1",img);
cvWaitKey(0);
cvReleaseImage(&img);
cvDestroyWindow("Example1");
return a.exec();
}
@
mainwindow.cpp
@#include "mainwindow.h"
#include "ui_mainwindow.h"
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);

}

MainWindow::~MainWindow()
{
delete ui;
}

@
mainwindow.ui
@<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
<class>MainWindow</class>
<widget class="QMainWindow" name="MainWindow">
<property name="geometry">
<rect>
<x>0</x>
<y>0</y>
<width>797</width>
<height>525</height>
</rect>
</property>
<property name="windowTitle">
<string>MainWindow</string>
</property>
<widget class="QWidget" name="centralWidget">
<widget class="QPushButton" name="pushButton">
<property name="geometry">
<rect>
<x>350</x>
<y>330</y>
<width>113</width>
<height>32</height>
</rect>
</property>
<property name="text">
<string>done</string>
</property>
</widget>
<widget class="QGraphicsView" name="input">
<property name="geometry">
<rect>
<x>50</x>
<y>70</y>
<width>256</width>
<height>192</height>
</rect>
</property>
</widget>
<widget class="QGraphicsView" name="output">
<property name="geometry">
<rect>
<x>490</x>
<y>70</y>
<width>256</width>
<height>192</height>
</rect>
</property>
</widget>
</widget>
<widget class="QMenuBar" name="menuBar">
<property name="geometry">
<rect>
<x>0</x>
<y>0</y>
<width>797</width>
<height>22</height>
</rect>
</property>
<widget class="QMenu" name="menuOpenCV">
<property name="title">
<string>OpenCV</string>
</property>
</widget>
<addaction name="menuOpenCV"/>
</widget>
<widget class="QToolBar" name="mainToolBar">
<attribute name="toolBarArea">
<enum>TopToolBarArea</enum>
</attribute>
<attribute name="toolBarBreak">
<bool>false</bool>
</attribute>
</widget>
<widget class="QStatusBar" name="statusBar"/>
</widget>
<layoutdefault spacing="6" margin="11"/>
<resources/>
<connections/>
</ui>
@

The error message i get is this..

error: symbol(s) not found for architecture x86_64
error: linker command failed with exit code 1 (use -v to see invocation)

[SGaist]

Hi and welcome to devnet,

Are both OpenCV and Qt built for 64 bit ?

If so, what symbols are missing ?

[joned]

I don't know either which symbols should be missing...
The Qt it built using 64 bit, i am not sure about the openCV though.. I have 2 version of openCV one from Macports, and the other one is compiled using cmake which is the one i am linking to in my .pro.

[SGaist]

The error message should contain a list of the missing symbols

[joned]

@01:42:53: Running steps for project test...
01:42:53: Configuration unchanged, skipping qmake step.
01:42:53: Starting: "/usr/bin/make"
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang++ -headerpad_max_install_names -Wl,-syslibroot,/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.10.sdk -mmacosx-version-min=10.7 -Wl,-rpath,/Users/keerthikanratnarajah/Qt/5.4/clang_64/lib -o test.app/Contents/MacOS/test main.o mainwindow.o moc_mainwindow.o -F/Users/keerthikanratnarajah/Qt/5.4/clang_64/lib -L/usr/local/lib -lopencv_core -framework QtWidgets -framework QtGui -framework QtCore -framework DiskArbitration -framework IOKit -framework OpenGL -framework AGL
Undefined symbols for architecture x86_64:
"_cvDestroyWindow", referenced from:
_main in main.o
"_cvLoadImage", referenced from:
_main in main.o
"_cvNamedWindow", referenced from:
_main in main.o
"_cvShowImage", referenced from:
_main in main.o
"_cvWaitKey", referenced from:
_main in main.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make: *** [test.app/Contents/MacOS/test] Error 1
01:42:53: The process "/usr/bin/make" exited with code 2.
Error while building/deploying project test (kit: Desktop Qt 5.4.0 clang 64bit)
When executing step "Make"
01:42:53: Elapsed time: 00:00.@

[SGaist]

Your pro file is wrong

@
LIBS += -L/usr/local/lib
-lopencv_core
-lopencv_imgcodecs
-lopencv_highgui
@

should be

@
LIBS += -L/usr/local/lib
-lopencv_core
-lopencv_imgcodecs
-lopencv_highgui
@

[joned]

I found the solution..

https://qt-project.org/forums/viewthread/35646