@abhisit said in How to debug / backtrace the call stack?:

Can I use try...catch() like below code?

No, there is not even a try block in that code and you can't put main() call into a try block as it is called by the loader of the OS, not by you.
You can't use exceptions to catch segmentation faults. You need to run a debug build of your app to see where exactly it crashes.

@skylendar

you shortened the log, so I can't see the GDB version. Please check these.

Also, GDB must be python enabled, and last the python dumper script must be loaded. Have you checked the directories?

Regards

Hi,

Why are you mixing both like that ?

Thanks @koahnig and @aha_1980.
I will setup a smaller Project an then do the recommended steps.
Regards...

@jsulm there was in fact a problem with window3d() that MinGW didnt complain about! Thanks!
@JonB no I had commented out only up to the second screenshot, so that's why this was the problem.
And about the second issue, to be honest I adapted the constructor from an older version of the application and it also had &argc. At one point I also noticed it and now I tried out both and both work.

By build a debug version do you mean adding -DDEBUG -g to CFLAGS in my makefile?
Hooray! Adding the -DDEBUG -g flags to my makefile fixed it!
Thank you @aha_1980! I googled for this but nothing really came up, thanks!

how about changing to MinGW 64 ?

Thanks for this Adam. It seems that disabling Load .gdbinit does the trick. Do you know why this is a problem?

What does you code do ?

@SGaist thank you so much.I solved problem by changing setup file

yes it does

Ahh ok. Thanks alot. That clears it up for me!

Hi,

Do you have gdbserver installed on your device ?

@Chris-Kawa Hi thanks for your reply. For some reason, though, it has started working again. All i changed was I added QWidget::resizeEvent(pEvent); to the GameView class and it started working. However, here is where it gets weird. when i remove that line it still works, so effectively i have changed nothing and it started working

I have the same problem, did you find any solution for this ?

You're welcome !

Since you have it working now, please update the thread title prepending [solved] so other forums users may know a solution has been found :)

@Tusharh
Hi and welcome to devnet

A featrure as you request may be latest with larger projects too much for the debugger to handle.

The closest to get such a behaviour is to use F11 and Shift+F11. F11 will enter every possible method and Shift+F11 will help you to run the remainder of the method. IMO sufficient enough to get a really detailed anaylsis of source code.

It was because I was in instruction-wise operation mode. Unchecking Debug → Operate By Instruction solved my problem.

To add to my fellow and maybe a silly question but since you build Qt yourself did you do a debug_and_release build ?

Thanks for replying to my Questions.
Sorry for replying so late.
Also regarding my question of using lldb as debugger it is not hitting the break point which i had set in QtCreator project.

Now i tried installing gdb debugger it works,But for Non-Qt Project it fails to load the debugging symbols.
But using LLDB debugger issue is still persists.

Second Question of resolving the issue of Library not loaded by executable.
I tried using :
otool -L ABC.exe

and it showed me the dependent .dylib and there path where missing But i tried changing it via

install_name_tool -change <old> <new> <exe>

But i got same error.Then i set the DYLD_LIBRARY_PATH inside my Qt Project under Project > Run>Run Environment >

I hardcoded the path for Debug external Libraries.But how it work for Release external Library.
I need to again amend that for Release Build ?
I am currently using Xcode 6.3.

Hi, welcome to devnet.

Qt (not QT which is Apple QuickTime) is just a library. It has nothing to do with debugging.
C++ language doesn't have such annotations so features like this depend on the compiler and debugger you use.

The supported toolchains on windows include MCVC+CDB and MinGW+gdb.

I'm not sure about the second combo, but AFAIK there is no (official at least) way to do that with MSVC and CDB. There is an undocumented .natstepfilter file that you can edit to mark some functions to be stepped over, but I personally never managed to make it work and I'm not sure if they apply to the CDB outside VS either. Anyway a few words about it here. Would love to hear from you if you get it to work.

See https://qt.gitorious.org/qt/qtdeclarative/source/3f2eabc8d90c4ee535cb0a2500e033171e203537:src/plugins/qmltooling and in particular https://qt.gitorious.org/qt/qtdeclarative/source/3f2eabc8d90c4ee535cb0a2500e033171e203537:src/plugins/qmltooling/shared/qpacketprotocol.cpp