Qt desktop app crashing at startup

Jennise Hall

Code that has been working suddenly started crashing at startup. I didn't update any thing between working and crash state. (e.g. xcode) The stack trace isn't providing information that makes any sense. My initial application has been running for months without start up issues. I am hoping someone can help me find a trouble shooting direction. (Or, if I'm lucky, an 'Ah ha' moment.)

I have a minimal example. This was created with QtCreator's basic template. I added a QListWidget and QPushButton in the .ui file (not included here but I can upload it.)

I appreciate any help you can give.

main.cpp

#include "DummyMainWindow.h"

#include <QApplication>
#include <QDebug>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    DummyMainWindow w;
    w.show();
    qDebug() << "Is Application running";
    maireturn a.exec();
}

DummyMainWindow.h

#ifndef DUMMYMAINWINDOW_H
#define DUMMYMAINWINDOW_H

#include <QMainWindow>

QT_BEGIN_NAMESPACE
namespace Ui {
class DummyMainWindow;
}
QT_END_NAMESPACE

class DummyMainWindow : public QMainWindow
{
    Q_OBJECT

public:
    DummyMainWindow(QWidget *parent = nullptr);
    ~DummyMainWindow();

private:
    Ui::DummyMainWindow *ui;
};
#endif // DUMMYMAINWINDOW_H

DummyMainWindow.cpp

#include "DummyMainWindow.h"
#include "ui_DummyMainWindow.h"

DummyMainWindow::DummyMainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::DummyMainWindow)
{
    ui->setupUi(this);
}

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

An image of the stack trace:

My environment:
Apple M4Pro
MacOs - Sequoia 15.7.3
Apple clang version 17.0.0 (clang-1700.0.13.3)
Target: arm64-apple-darwin24.6.0
Thread model: posix
Apple Swift version 6.1 (swiftlang-6.1.0.110.21 clang-1700.0.13.3)
Target: arm64-apple-macosx15.0
C++17
Product: Qt Creator 15.0.0
Based on: Qt 6.8.1 (Clang 15.0 (Apple), arm64)
Built on: Nov 27 2024 08:36:08
From revision: 3ac6a5956d

Nils Sjoberg

Change to maireturn a.exec();

SGaist

Hi,

Which version of Qt are you using ?
Is maireturn a typo ?

Jennise Hall

Darn it. It is a typo. Now it's working. I apologize for wasting your time. I'm not sure when the typo creeped in. I'm going to strip down my application in to the simplest repeatable case.

Qt 6.8.1

JonB

@Jennise-Hall said in Qt desktop app crashing at startup:

Darn it. It is a typo. Now it's working.

Pardon?

You pasted maireturn a.exec(); which obviously means your code could not compile. So how come there is a stack trace showing showing it running and inside the exec() and you say it crashed?

Jennise Hall

Yes, That has me stumped. You're right it wouldn't have compiled with the typo. So, the typo must have happened when I pasted the code but, I'm no longer sure because once I fixed that line of code the program started running consistently. Nothing about this crash makes any sense to me. I am going to strip the actual application down to the simplest point that generated a crash. I'm also thinking I should update to Qt 6.11.

SGaist

I would also check whether you have somewhere a macro that has that name or maybe a define.

JonB

The word "maireturn" is a Tagalog (Filipino) verb that translates to "to be able to return" or "can be returned" in English

:)

Pl45m4

@JonB

"Mai" is month May in German.
So maireturn a.exec() should return an int 10 :))
(months to May)

:P

SGaist

I wasn't expecting a linguistic analysis for a typo :-D

Jennise Hall

@SGaist

LOL

useful information though.

Jennise Hall

Well, my application is back to running. I got frustrated trying to strip down my application and decided to throw a couple of spitballs at the wall. Not for the first time, I deleted the pro.user file making sure some of the settings that were not included in the DummyMainWindow project. Re-opening the project after that and the project was once again running. I am not really sure what happened but I'm working again. So I am going to close this topic.

Thanks for catching the typo...and for the "linguistic analysis" of the typo. LOL

SGaist

@Jennise-Hall said in Qt desktop app crashing at startup:

@SGaist

LOL

useful information though.

Agreed ! :-)