Why is my QT Application breaking in disassembly code on debug start?

[jabroni]

@SamiV123 @JoeCFD

I am using QT Creator as my build and debug tool. This is not an issue with the code. I just created a new QT project with the base code that is provided by default, and that gives me the same error:

#include "mainwindow.h"

#include <QApplication>

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

My QT Creator "about" window:

[hskoglund]

If you have an anti-virus app running, try disable it.

[jabroni]

@hskoglund Unfortunately no luck. I only have standard windows anti virus protection. I disabled firewall and all settings under "Virus & Threat Protection Settings", amongst other security settings.

[hskoglund]

And if you try another project, for example Application in Examples, I'm guessing you get the same crash?

[jabroni]

@hskoglund Yep - Just tried with QT 5.14.1 and 5.15.2 and both crashed.

[ChrisW67]

@jabroni What is the stack backtrace when the failure occurs. The original error message is from attempting to access memory that does not belong to your process or accessing through a null pointer. In this case the address is in EAX and is 0xbaadf00c (which looks suspiciously like a common flag value 0xbaadf00d (bad food)).

If you put a breakpoint on the first line inside main() does the program get that far?

What non-Qt libraries, ActiveX controls etc are linked to your application?

[jabroni]

@ChrisW67 I'll just focus on the main.ccp file in the Applications example project now as that should be what everyone else has.

Just as my program, the "crash" occurrs once the .show() function is called. In this case it's mainWin.Show(). Stepping over/into that fails to disassembler:

and this is the stack trace:

Also, in my main application I am developing, the only external library that is used is QWT 6.1.3 (as far as I am aware - please let me know if there's a way I can check this). However, even with the Application example project which is 80 lines of code the same error occurs.

[hskoglund]

Just guessing, but are you using OneDrive for running Qt?

[jabroni]

@hskoglund I do have OneDrive enabled, however my QT application runs out of my local git folder, and QT is installed in C:\Qt.

[hskoglund]

Ok. And just to clarify, if you rebuild the Application example in Release mode it does not crash, it only crashes in Debug mode?

[jabroni]

@hskoglund So:

Release Mode
Start with debugging = same crash
Start with no debugging = no crash

Debug mode
Same as above

So it looks like debug run is the issue here I think.

And these are the buttons I am referring to when I say "start with debugging":

[hskoglund]

Maybe you can just tick the checkbox to ignore those breakpoints:

[jabroni]

@hskoglund well okay that omits that error from startup haha. Which solves that problem, however if I enter a breakpoint during debug runtime of my application it breaks into disassembler code:

        ntdll!DbgBreakPoint:
0x772c8c00                   int     3
0x772c8c01  <+    1>         ret
0x772c8c02  <+    2>         int     3

[jabroni]

@jabroni anyone have anything extra on this? really not sure what my options are here :\

[ngocanhnu]

@jabroni Hi, I've met same issue with you.
But not as your case, my code have a problem with "tr" function when using with static variable.
I fix that follow the guide here https://forum.qt.io/topic/33568/qt-tr-not-working-if-i-am-using-in-static-member
Hope it can help you.

[jabroni]

@ngocanhnu I don't think that's quite the same problem, but thank you.