executable runs fine from local directory / throws error with IDE.

JKSH

Let's take a step back. Do an officially-supported Hello World test:

Open Qt Creator
Create a new project: "File" -> "New File or Project..." -> "Application" -> "Qt Widgets Application"
Click the green button.

Does this work? If so, examine the .pro file and look for differences with yours.

Technologist

Ok, I built the "official" hello world app which worked flawlessly. The #include <QApplication>
didn't throw an error.

I ran the "Unofficial" hello world and compilation stopped secondary to error: qapplication.h: No such file or directory

Ive compared both .pro files and I don't see why the unofficial can't find the same include that the "official" hello world can. I'll post

"official" HW .pro file/main

#-------------------------------------------------
#
# Project created by QtCreator 2015-04-17T08:55:34
#
#-------------------------------------------------

QT       += core gui

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

TARGET = TestApp
TEMPLATE = app


SOURCES += main.cpp\
        mainwindow.cpp

HEADERS  += mainwindow.h

FORMS    += mainwindow.ui

main.cpp

#include "mainwindow.h"
#include <QApplication>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    MainWindow w;
    w.show();

    return a.exec();
}

"Unofficial" HW File
'''

Unofficial Hello world

.pro file - qapp/qbutton not found

QT       += core

QT       -= gui

TARGET = HelloWorldUnofficialvsTestApp
CONFIG   += console
CONFIG   -= app_bundle

TEMPLATE = app


SOURCES += main.cpp

#include <qapplication.h>
#include <qpushbutton.h>


int main( int argc, char **argv )
{
    QApplication a( argc, argv );

    QPushButton hello( "Hello world!", 0 );
    hello.resize( 100, 30 );

    a.setMainWidget( &hello );
    hello.show();
    return a.exec();
}

JKSH

@Technologist said:

Ive compared both .pro files and I don't see why the unofficial can't find the same include that the "official" hello world can.

By default, the Qt Core and Qt GUI modules are available for your project. Let's see how the .pro files change this.

"official" HW .pro file
QT += widgets

This line says, "ADD the Qt Widgets module to my project". This is required to find QApplication and QPushButton, because they belong to the Qt Widgets module. They used to be in the Qt GUI module in Qt 4, but Qt 5 has a new structure. This is one big reason to avoid old tutorials and stick to new ones.

Unofficial Hello world
QT -= gui

This line says, "EXCLUDE the Qt GUI module from my project". This removes all GUI functionality, like OpenGL. Since you want to build an OpenCV app, you probably don't want this option!

See https://doc.qt.io/qt-5/qtmodules.html for a list of all available modules.

Technologist

That shows that the configuration problem of .pro file was human error. It found my qt header files. Thanks for the pointer on opel GL etc. This solution rules out a single error behind both. This problem is fixed however the first problem persists: the IDE crashes when I build the "Show Picture" routine, but runs perfectly when I execute it from build directory. Do I need to close out this ticket and reopen it or finish out here?

Thanks for your time

JKSH

@Technologist said:

That shows that the configuration problem of .pro file was human error. It found my qt header files. Thanks for the pointer on opel GL etc. This solution rules out a single error behind both. This problem is fixed however the first problem persists: the IDE crashes when I build the "Show Picture" routine, but runs perfectly when I execute it from build directory. Do I need to close out this ticket and reopen it or finish out here?

Thanks for your time

You're welcome :)

Yes, this little excursion helped us to establish that your installation of Qt and the IDE are fine. So, the problem probably lies in your project configuration or environment.

I just noticed that you have Qt and Qt Creator in your PATH. This is very bad, because they both contain different (and incompatible) versions of the same DLL (e.g. Qt5Core.dll). Remove them from your PATH. There is no need for anything Qt-related to be in the PATH, and having them there is the cause of many mysterious crashes.

After cleaning your PATH, try running your program again. (To do it outside the IDE the proper way, see http://wiki.qt.io/Deploy_an_Application_on_Windows )

In general, MSVC and MinGW are incompatible. Qt Creator is a Qt-built program too, which uses MSVC 2010-built Qt DLLs. I also noticed that your copy OpenCV is built with MSVC 2012. I'm not sure if this is compatible with your MinGW-built app.

You can continue posting here, as it's still about your original post.

Technologist

FYI the platform was built using cmake and mingw, not MSVS (I don't have msvs on the system.) -- if that's coming across from the ?path?. Was it this line: %OPENCV%\buildx86\vc11Honestly I think I put it in the path mistakenly. Can I remove it?

OK cleaned my path. No more missing qt files with Widgets addition to pro file. Application still continue to crash in intialization phase. Sometimes it will throw this error a lot of the time or just open a window and crash. Below it can't find an opencv file.

The program can't start because libgcc_s_dw2-1.dll is missing from your computer Try installing the program to fix this problem.

New local path: C:\OpenCV-2.3.1\bin;C:\OpenCV-2.3.1\install\include\opencv2;C:\OpenCV-2.3.1\lib;
System path:%OPENCV%\build\x86\vc11\bin; c:\OpenCV-2.3.1\bin;C:\opencv-win\opencv\sources\modules;

error :C:\Users\Technologist\Documents\NewOne\main.cpp:2: error: opencv2/core/core.hpp: No such file or directory #include <opencv2/core/core.hpp>
^
pro. file:

QT       += core

QT       += gui
QT       += widgets

TARGET = NewOne
CONFIG   += console
CONFIG   -= app_bundle

TEMPLATE = app

SOURCES += main.cpp

INCLUDEPATH += "C:/OpenCV-2.3.1/install/include/opencv2/"

LIBS += -LC:\OpenCV-2.3.1\lib\
    -lopencv_core2411.dll.a \
    -lopencv_highgui2411.dl.al \
    -lopencv_imgproc2411.dll.a \
    -lopencv_features2d2411.dll.a \
    -lopencv_calib3d2411.dll.a

#include <QCoreApplication>
#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
int main() {
        // read an image
        cv::Mat image= cv::imread("img.jpg");
        // create image window named "My Image"
        cv::namedWindow("My Image");
        // show the image on window
        cv::imshow("My Image", image);
        // wait key for 5000 ms
        cv::waitKey(5000);
        return 1;
}

SGaist

Don't include opencv2 in your INCLUDEPATH entry

INCLUDEPATH += "C:/OpenCV-2.3.1/install/include/"

Technologist

I don't see any opencv2 in your includepath unless you are referring to the opencv2 down the file directory from there.

INCLUDEPATH += "C:\OpenCV-2.3.1\install\include\opencv2"

Sorry, now I am feeling newbish.

SGaist

That's the point. Since you use:

#include <opencv2/core/core.hpp>

If you use INCLUDEPATH += "C:/OpenCV-2.3.1/install/include/opencv2/" then the headers won't be found because you are trying to include a file that would be searched like:
"C:/OpenCV-2.3.1/install/include/opencv2/opencv2/core/core.hpp".

So either remove opencv2 from your include lines or remove it from your INCLUDEPATH line.

JKSH

@Technologist said:

FYI the platform was built using cmake and mingw, not MSVS (I don't have msvs on the system.) -- if that's coming across from the ?path?. Was it this line: %OPENCV%\buildx86\vc11

Yes, it was that line. "VC11" represents Visual Studio 2012.

Honestly I think I put it in the path mistakenly. Can I remove it?

I don't know, as I've never used OpenCV myself. How does OpenCV recommend you set up your libraries?

OK cleaned my path. No more missing qt files with Widgets addition to pro file. Application still continue to crash in intialization phase. Sometimes it will throw this error a lot of the time or just open a window and crash. Below it can't find an opencv file.
The program can't start because libgcc_s_dw2-1.dll is missing from your computer Try installing the program to fix this problem.

That's not an error that can only happen "some of the time" for a particular setup -- it either happens all of the time, or it won't happen.

I suspect that you are trying to launch your app in different ways but then combining their results into one observation. Please be systematic in your investigations: Describe what you do leading up to a specific crash (e.g. "This happens I try to launch my app from the IDE" and "That happens when I try to launch my app from the build directory")

Note: Launching from a build directory is like trying to run a deployed application. Follow http://wiki.qt.io/Deploy_an_Application_on_Windows carefully

Technologist

I suspect that you are trying to launch your app in different ways but then combining their results into one observation.. Please be systematic in your investigations.

The more systematic the better. I am trying to get all my apps, as with any good scientific analysis, running from the same baseline. We have done most of that already by clearing up the header and include file issues, and this has prepared the way for a final solution, easier to see with less stuff being wrong. Now its finally the library error they all seem to share.

Thx for your time.

Below: :-1: error: cannot find -llibopencv_core2411.dll.a  :-1: error: cannot find -llibopencv_highgui2411.dll.a

.pro

QT       += core
QT       += widgets
QT       += gui

TARGET = AnotherWack
CONFIG   += console
CONFIG   -= app_bundle

TEMPLATE = app


SOURCES += main.cpp

INCLUDEPATH += "C:/OpenCV-2.3.1/install/include/"

LIBS += -LC:/OpenCV-2.3.1/lib \
        -llibopencv_core2411.dll.a \
        -llibopencv_highgui2411.dll.a \

main

#include <QCoreApplication>
#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>

int main() {
        // read an image
        cv::Mat image= cv::imread("img.jpg");
        // create image window named "My Image"
        cv::namedWindow("My Image");
        // show the image on window
        cv::imshow("My Image", image);
        // wait key for 5000 ms
        cv::waitKey(5000);
        return 1;
}

mcosta

@Technologist said:

-llibopencv_core2411.dll.a

Hi,

if you use the flag -l you have to omit the lib prefix and the extensions -llibopencv_core2411

Technologist

I'm no longer getting the include and library errors that I was. The main error was getting a build error with a working executable. Now after installing these changes, I get the build error and executable error (they are the same) . Somehow, am chagrin to say, I can't account for the change.They both crash now. I wanted to try putting the DLL in with the executable to see if that would work, but the relevant 5 project dlls were gone (??). I had to poach them from an apparent windows directory vc 11 and copy them to the library that couldn't find them. The same error would continue.

Present code:
main.cpp

#include <QCoreApplication>
#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>

int main() {

    // read an image
    cv::Mat image= cv::imread("img.jpg");
    // create image window named "My Image"
    cv::namedWindow("My Image");
    // show the image on window
    cv::imshow("My Image", image);
    // wait key for 5000 ms
    cv::waitKey(5000);

    return 1;
}

.pro


QT       += core

QT       += gui
QT       += widgets

TARGET = NewOne
CONFIG   += console
CONFIG   -= app_bundle

TEMPLATE = app

SOURCES += main.cpp

INCLUDEPATH += C:/OpenCV-2.3.1/install/include/

LIBS += -LC:\OpenCV-2.3.1\lib\
    -lopencv_core2411 \
    -lopencv_highgui2411 \
    -lopencv_imgproc2411 \
    -lopencv_features2d2411\
    -lopencv_calib3d2411

SGaist

Then just to be sure: which Qt package are you using ?

Technologist

The version is qt 5.4
Using 64 bit os

On a few directories I made them the version of the tutorial (OpenCV-2.3.1) to stay on track, but the overall version was 2.4.11 that was downloaded and installed.