On 6/13/12, André Pönitz <andre.poen...@mathematik.tu-chemnitz.de> wrote: > On Wed, Jun 13, 2012 at 04:25:59PM -0400, Josiah Bryan wrote: >> I'm attempting to debug an odd problem wherein my program (http:// >> code.google.com/p/dviz/) crashes when displaying certain UTF-8 >> strings. That's not really why I'm emailing - the problem I'd like >> your help with is that I'm unable to run the program in "Debug" mode >> in Qt Creator on Windows 7. >> >> I've set the project in Qt Creator to the "Debug" build and tried to >> run it in the Debugger (F5). The program builds and launches - >> however, before the main UI can appear, an error dialog titled >> "Microsoft Visual C++ Runtime Library" appears giving the following >> error: "This application has requested the Runtime to terminate in an >> unusual way. Please contact the application's support team for more >> information." >> >> Below the console output from Qt Creator. As you can guess, it does >> run correctly in "Release" mode in Qt Creator (just crashes when the >> user performs a certain UI action - hence why I want to run it in >> Debug mode. Note that it does not crash on linux in gdb or in release >> mode - so this is specific to Windows and the debugger in Qt Creator.) > > Assuming that the "release" mode takes roughly the same code path > as the "debug" mode (i.e. no major #ifdef surgery in your code), > the problems that are indicated by the output
Correct, no #ifdef's for debug mode - a few for Windows/Linux, but that's about it. > > QObject: Cannot create children for a parent that is in a different > thread. [...] > > QCoreApplication::applicationFilePath: Please instantiate the > QApplication object first [...] > > QWidget: Must construct a QApplication before a QPaintDevice > > Invalid parameter passed to C runtime function. > > They would exist in "release" mode as well. So it does not run > "correctly" there, rather "by accident". Perhaps - the thing is, these errors are not generated in Release mode - e.g. no complains about instantiating a QApplication first, QWidget doesn't complain about a QApplication before a QPaintDevice - given that they are running the same code path, wouldn't these errors output in Release mode as well? >> You'll note there are comments in the console output below regarding >> constructing QApplication before QPaintDevice and other references to >> QApplication - well, I don't know why it's complaining about that, >> because QApplication is created on the second line of code to be >> executed in in main() - see >> http://code.google.com/p/dviz/source/browse/trunk/src/main.cpp#36 for >> proof. > > The second line of 'main' is not the second line of code that ie > executed. There are things like constructions of global objects > that go before 'main'. Granted. However, None of *my* code is executed prior to QApplications creation - any global static objects are created using a static ::instance() model (check static pointer at call time, create if not exists at that time) - sort of like a "pull" model to create any needed global pointers. The real problem here is that Qt Creator / Debugger doesn't even bother to give a stack trace of where it stopped at - just the MSVC error dialog, no stack trace. If it would just give some info about *where* it stopped, I could trace it from there. As it sits now, I'm flailing in the dark at more than 50K SLOC. Any thoughts as to why no stack trace from the debugger? > > Start with tracking down global objects, avoid them, or at the > very least don't do anything that needs a fully constructed > Q[Core]Application. Check your thread creation and thread affinity > of your QObjects. I'll double-check globals, but a stack trace is really what's needed here anyway - debugger just says "Application exited with exit code exit-code="03"" (Yes, I googled that - no, the only three results I found did not help.) Thanks for your help and advice! -Josiah -- Josiah Bryan 765-215-0511 josiahbr...@gmail.com _______________________________________________ Interest mailing list Interest@qt-project.org http://lists.qt-project.org/mailman/listinfo/interest
