qt sigfpe arithmetic exception

NoobDude12343

I'm pretty new to qt and i'm trying to create a widget that showing my webcam using qt and opencv. As the title has stated that i'm stuck at tracking the sigfpe arithmetic exception. The odd thing about this issues is that 2 days ago, my code worked, but now it's not. After doing some research, i discovered that this issues have been addressed in multiple topic, with multiple solving method, but i don't think it would work for me

ok, lat me wrap things up a bit, when i run my code, the process ended forcefully, crashed. Then i run debugger, which indicated "sigfpe arithmetic exception" in line 6 (myvideocapture.cpp), line 10 (mainwindow.cpp) and line 8(main.cpp) i'll later mark the line for easier visualization

here's my code:
.pro:

#-------------------------------------------------
#
# Project created by QtCreator 2019-08-10T12:27:53
#
#-------------------------------------------------

QT       += core gui

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

TARGET = TutorialOpenCV
TEMPLATE = app

# The following define makes your compiler emit warnings if you use
# any feature of Qt which has been marked as deprecated (the exact warnings
# depend on your compiler). Please consult the documentation of the
# deprecated API in order to know how to port your code away from it.
DEFINES += QT_DEPRECATED_WARNINGS

# You can also make your code fail to compile if you use deprecated APIs.
# In order to do so, uncomment the following line.
# You can also select to disable deprecated APIs only up to a certain version of Qt.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0

CONFIG += c++11

SOURCES += \
        main.cpp \
        mainwindow.cpp \
        myvideocapture.cpp

HEADERS += \
        mainwindow.h \
        myvideocapture.h

FORMS += \
        mainwindow.ui

# Default rules for deployment.
qnx: target.path = /tmp/$${TARGET}/bin
else: unix:!android: target.path = /opt/$${TARGET}/bin
!isEmpty(target.path): INSTALLS += target

win32:CONFIG(release, debug|release): LIBS += -L$$PWD/../../../../../opencv/build/x64/vc15/lib/ -lopencv_world451
else:win32:CONFIG(debug, debug|release): LIBS += -L$$PWD/../../../../../opencv/build/x64/vc15/lib/ -lopencv_world451d
else:unix: LIBS += -L$$PWD/../../../../../opencv/build/x64/vc15/lib/ -lopencv_world451

INCLUDEPATH += C:\opencv\build\x64\vc15
LIBS += C:\opencv\build\x64\vc15\lib\opencv_world451.lib
LIBS += C:\opencv\build\x64\vc15\lib\opencv_world451d.lib


INCLUDEPATH += $$PWD/../../../../../opencv/build/include
DEPENDPATH += $$PWD/../../../../../opencv/build/include


INCLUDEPATH += C:\opencv\release\install\include


LIBS += C:\opencv\release\bin\libopencv_core451.dll
LIBS += C:\opencv\release\bin\libopencv_highgui451.dll
LIBS += C:\opencv\release\bin\libopencv_imgcodecs451.dll
LIBS += C:\opencv\release\bin\libopencv_imgproc451.dll
LIBS += C:\opencv\release\bin\libopencv_features2d451.dll
LIBS += C:\opencv\release\bin\libopencv_calib3d451.dll

INCLUDEPATH += C:\opencv\release\install\include\opencv2
INCLUDEPATH += C:\opencv\release\install\include\opencv
INCLUDEPATH += C:\opencv\build\include
INCLUDEPATH += C:\opencv\release\include
LIBS += C:\opencv\release\install\x64\mingw\bin\libopencv_core451.dll
LIBS += C:\opencv\release\install\x64\mingw\bin\libopencv_highgui451.dll
LIBS += C:\opencv\release\install\x64\mingw\bin\libopencv_imgcodecs451.dll
LIBS += C:\opencv\release\install\x64\mingw\bin\libopencv_imgproc451.dll
LIBS += C:\opencv\release\install\x64\mingw\bin\libopencv_features2d451.dll
LIBS += C:\opencv\release\install\x64\mingw\bin\libopencv_calib3d451.dll

myvideocapture.cpp:

#include "myvideocapture.h"
#include <QDebug>

MyVideoCapture::MyVideoCapture(QObject *parent)
    : QThread { parent }
    , mVideoCap { ID_CAMERA }
{
}
///////////////////////this line///////////////////////////////
void MyVideoCapture::run()
{
    if (mVideoCap.isOpened())
    {
        while (true)
        {
            mVideoCap >> mFrame;
            if (!mFrame.empty())
            {
                cv::rectangle(mFrame, cv::Point(10, 10), cv::Point(401, 401), cv::Scalar(0, 0, 255), 1);

                mPixmap = cvMatToQPixmap(mFrame);
                emit newPixmapCaptured();
            }
        }
    }
}

QImage MyVideoCapture::cvMatToQImage(const cv::Mat &inMat)
{
    switch (inMat.type())
    {
        // 8-bit, 4 channel
        case CV_8UC4:
        {
            QImage image(inMat.data, inMat.cols, inMat.rows, static_cast<int>(inMat.step), QImage::Format_ARGB32);
            return image;
        }
        // 8-bit, 3 channel
        case CV_8UC3:
        {
            QImage image(inMat.data, inMat.cols, inMat.rows, static_cast<int>(inMat.step), QImage::Format_RGB888);
            return image.rgbSwapped();
        }
        // 8-bit, 1 channel
        case CV_8UC1:
        {
    #if QT_VERSION >= QT_VERSION_CHECK(5, 5, 0)
            QImage image(inMat.data, inMat.cols, inMat.rows, static_cast<int>(inMat.step), QImage::Format_Grayscale8);
    #else
            static QVector<QRgb>  sColorTable;

            // only create our color table the first time
            if (sColorTable.isEmpty())
            {
                sColorTable.resize(256 );

                for (int i = 0; i < 256; ++i )
                {
                    sColorTable[i] = qRgb(i, i, i );
                }
            }

            QImage image(inMat.data,
                         inMat.cols, inMat.rows,
                         static_cast<int>(inMat.step),
                         QImage::Format_Indexed8 );

            image.setColorTable(sColorTable );
    #endif
            return image;
        }
        default:
        {
            qWarning()<< "ASM::cvMatToQImage()- cv::Mat image type not handled in switch:" << inMat.type();
            break;
        }
    }
    return QImage();
}

QPixmap MyVideoCapture::cvMatToQPixmap(const cv::Mat &inMat)
{
    return QPixmap::fromImage(cvMatToQImage(inMat));
}

mainwindow.cpp:

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include "myvideocapture.h"

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    mOpenCV_videoCapture = new MyVideoCapture(this);
////////////////////////this line////////////////////////////////
    connect(mOpenCV_videoCapture, &MyVideoCapture::newPixmapCaptured, this, [&]()
    {
        ui->opencvFrame->setPixmap(mOpenCV_videoCapture->pixmap().scaled(500, 500));
    });
}

MainWindow::~MainWindow()
{
    delete ui;
    mOpenCV_videoCapture->terminate();
}

void MainWindow::on_iniciarOpenCV_button_clicked()
{
    mOpenCV_videoCapture->start(QThread::HighestPriority);
}

main.cpp:

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

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    a.setStyle("fusion");
    MainWindow w;
////////////////////this line///////////////////////////
    w.show();
    return a.exec();
}

Christian Ehrlicher

As always when a crash happens - use a debugger to see where and why it crashes.

Christian Ehrlicher

@NoobDude12343 said in qt sigfpe arithmetic exception:

ui->opencvFrame->setPixmap(mOpenCV_videoCapture->pixmap().scaled(500, 500));

And this creates a race condition since two threads may access this data. Send the image/pixmap via signals/slots instead.

NoobDude12343

thanks for replying @Christian-Ehrlicher , now i face another error, which is "lnk1107 invalid or corrupt file cannot read 0x458"
i google this and couldn't found anything, not the 0x458 particularly, any insight?

jsulm

@NoobDude12343 said in qt sigfpe arithmetic exception:

corrupt file

What file exactly is that? Please post whole error message.

NoobDude12343

@jsulm ah, it's myvideocapture.cpp, main and mainwindow.cpp (according to the debugger). but now i face yet another challenge, which has been mention above, any idea?

jsulm

@NoobDude12343 Do you mean the issue @Christian-Ehrlicher replied to?

Pablo J. Rogina

@NoobDude12343 said in qt sigfpe arithmetic exception:

lnk1107 invalid or corrupt file

It's a linker issue. It looks like you're messing up with some library, not using the proper one (maybe some wrong file from OpenCV?). See for instance this SO question.

NoobDude12343

@jsulm yeah