gui not showing, or closing to fast to see

micha_eleric

my main.cpp code:

#include "CGUI.h"

int main(int argc, char **argv)
{
	std::cout << "__name__";
    QApplication app (argc, argv);
    CNC::CGUI myapp;
	myapp.show();
	return app.exec();
}

main code from https://doc.qt.io/qt-5/qtwidgets-richtext-orderform-example.html

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    MainWindow window;
    window.resize(640, 480);
    window.show();
    window.createSample();
    return app.exec();
}

they look equivalent.
i am not getting any errors from compiling, and from running. why is window not showing?

answer: code had an error, that crashed program, without giving any error messages, and try/catch does not catch it

Pl45m4

@micha_eleric

What kind of class is CGUI?

micha_eleric

@Pl45m4 said in gui not showing, or closing to fast to see:

@micha_eleric

What kind of class is CGUI?

class CGUI : public QMainWindow

Pl45m4

@micha_eleric

What exit code do you get?Set breakpoints and debug to see what happens. Does it crash or exit properly?!

micha_eleric

@Pl45m4

Press <RETURN> to close this window...

micha_eleric

@Pl45m4
can not find where this is printed. eclipse, i did. i am a wee bit new to qt creator

std::cout << "__name__";

QApplication app (argc, argv);

results in

The inferior stopped because it received a signal from the operating system.

Signal name : 
SIGSTOP
Signal meaning : 
Stopped (signal)

micha_eleric

i dont get it. it is erroring even like this

int main(int argc, char **argv)
{
    std::cout << "__name__";
    QApplication app (argc, argv);
    //CNC::CGUI myapp;
    //myapp.show();
    //return app.exec();
    return 1;
}

micha_eleric

@micha_eleric said in gui not showing, or closing to fast to see:

i dont get it. it is erroring even like this

int main(int argc, char **argv)
{
    std::cout << "__name__";
    QApplication app (argc, argv);
    //CNC::CGUI myapp;
    //myapp.show();
    //return app.exec();
    return 1;
}

this does not crash when run, but crashes with debug

jsulm

@micha_eleric On which OS.
What Qt version?
How did you install Qt?
Post the stack trace after crash.

CP71

@micha_eleric
Hi,
Try to delete all build folders from the explorer resource (release and debug), not clear from Qt Creator, and try this code (obviously, you see nothing because myapp.show is commented, but you can check if removing builder folder fixes the crash).
Only for curiosity. What is CNC? Maybe a namespace.

Pl45m4

@CP71 said in gui not showing, or closing to fast to see:

What is CNC? Maybe a namespace.

Probably...

@micha_eleric
To check, if nothing appears or if it's just gone too fast to recognize, you could reimplement the showEvent in your QMainWindow subclass and print some qDebug() from there (If debugging doesn't work for you, in this case)

micha_eleric

@CP71 said in gui not showing, or closing to fast to see:

@micha_eleric
Hi,
Try to delete all build folders from the explorer resource (release and debug), not clear from Qt Creator, and try this code (obviously, you see nothing because myapp.show is commented, but you can check if removing builder folder fixes the crash).
Only for curiosity. What is CNC? Maybe a namespace.

obviously, show was not commented out in the first code i posted.
CNC is the namespace.

micha_eleric

@jsulm said in gui not showing, or closing to fast to see:

@micha_eleric On which OS.
What Qt version?
How did you install Qt?
Post the stack trace after crash.

Qt Creator 4.11.0
Based on Qt 5.12.8 (GCC 9.3.0, 64 bit)
installed from Discover
no stack trace. if there is, i have not found it.

micha_eleric

@Pl45m4 said in gui not showing, or closing to fast to see:

@CP71 said in gui not showing, or closing to fast to see:

What is CNC? Maybe a namespace.

Probably...

@micha_eleric
To check, if nothing appears or if it's just gone too fast to recognize, you could reimplement the showEvent in your QMainWindow subclass and print some qDebug() from there (If debugging doesn't work for you, in this case)

void CGUI::showEvent(QShowEvent * /* event */)
    {
        qDebug() << "Date:" << QDate::currentDate();
        qDebug() << "Types:" << QString("String") << QChar('x') << QRect(0, 10, 50, 40);
        qDebug() << "Custom coordinate type:";
    }

had no output, and std::cout << "name";, not doing anything.
however, i did find the line that was crashing the program.

JonB

@micha_eleric said in gui not showing, or closing to fast to see:

had no output, and std::cout << "name";, not doing anything.

Perhaps std::flush() or std::endl to flush, else you won't get it if you crash later on?

however, i did find the line that was crashing the program.

And what was that then?

micha_eleric

@JonB said in gui not showing, or closing to fast to see:

@micha_eleric said in gui not showing, or closing to fast to see:

however, i did find the line that was crashing the program.

And what was that then?

//ui->pushButton_22->connect(ui->pushButton_22, SIGNAL(clicked()),this, SLOT(CGUI::Btn_test_clicked()) );  //?? old qt4
ui->pushButton_22->connect(ui->pushButton_22, &QPushButton::clicked, this, &CGUI::Btn_test_clicked);    //?? new qt5

CGUI::Btn_test_clicked exist
i tried inclosing in a try catch block, but still crashes

Pl45m4

@micha_eleric

Remove everything on the left before connect

micha_eleric

@Pl45m4 said in gui not showing, or closing to fast to see:

@micha_eleric

Remove everything on the left before connect

well, now that i added a few \n at end of some std::cout, that line is not crashing, but something else is. it was running in regular run, with that commented out.

that format was working on other buttons.
why remove "ui->pushButton_22->"?

micha_eleric

ok. this makes no sense
in the constructor

InitTestBoard();
std::cout << "constructor InitTestBoard finished \n" << std::flush;

    void CGUI::InitTestBoard()
    {
        std::cout << "InitTestBoard \n" << std::flush;
        try
        {
            std::cout << "InitTestBoard try begin \n" << std::flush;
            //?? test arduino board leds
            //ui->pushButton_22->connect(ui->pushButton_22, SIGNAL(clicked()),this, SLOT(CGUI::Btn_test_clicked()) );  //?? old qt4
            ui->pushButton_22->connect(ui->pushButton_22, &QPushButton::clicked, this, &CGUI::Btn_test_clicked);    //?? new qt5

            std::cout << "InitTestBoard try 2 \n" << std::flush;
            //?? Test Board/Motor wiring
            ui->textEdit_34->setFixedSize(30,  30);
            ui->textEdit_35->setFixedSize(30,  30);
            ui->textEdit_35->setFixedSize(30,  30);
            ui->textEdit_36->setFixedSize(30,  30);
            ui->textEdit_37->setFixedSize(30,  30);
            ui->textEdit_38->setFixedSize(30,  30);

            std::cout << "InitTestBoard try 3 \n" << std::flush;
            ui->textEdit_40->setFixedSize(30,  30);
            ui->textEdit_41->setFixedSize(30,  30);
            ui->textEdit_42->setFixedSize(30,  30);
            ui->textEdit_43->setFixedSize(30,  30);
            ui->textEdit_44->setFixedSize(30,  30);
            ui->textEdit_45->setFixedSize(30,  30);
            std::cout << "InitTestBoard try end \n" << std::flush;
        }
        catch(std::exception& e)
        {
            std::cout << "InitTestBoard catch begin \n" << std::flush;
            std::cout << e.what() << std::flush;
            MessageBoxError("InitTestBoard");
            std::cout << e.what()<< std::flush;
        }
    }

console output

__name__
InitTestBoard 
InitTestBoard try begin 
InitTestBoard try 2 
InitTestBoard try 3 
Press <RETURN> to close this window...

it is crashing at end of try{}?
crashing in a try{}, but not getting caught?

well, now, if i comment out

ui->textEdit_40->setFixedSize(30,  30);
ui->textEdit_41->setFixedSize(30,  30);

it does not crash on start

JonB

@micha_eleric
You have several things wrong. Whether they cause the crash I don't know, but let's start by sorting them out....

Remove your try ... catch. Qt does not throw C++ exceptions, and if you have a coding error/"crash" it won't catch it anyway.

ui->pushButton_22->connect(ui->pushButton_22, &QPushButton::clicked, this, &CGUI::Btn_test_clicked); //?? new qt5

@Pl45m4 already said this is wrong. You want:

connect(ui->pushButton_22, &QPushButton::clicked, this, &CGUI::Btn_test_clicked);    //?? new qt5

Before

ui->textEdit_40->setFixedSize(30,  30);
ui->textEdit_41->setFixedSize(30,  30);

let's put in something like:

qDebug() << ui->textEdit_40 << ui->textEdit_41;
// if previous line not acceptable to compiler remove it
qDebug() << ui->textEdit_40->objectName() << ui->textEdit_41->objectName();

If either of these "crash"/"go wrong", narrow down to textEdit_40 vs textEdit_41 one at a time. Is it because of just one of them, not the other? Or, does accessing either of them cause the problem?

At one point you said a SIGSTOP was reported. Now you talk about "crashing", or just exiting. In any case, are you compiling for debug and running inside the debugger? Does the debugger catch anything/stop/report anything when your code goes wrong or exits?