CODEWITHSUNDEEP
qt
shahina
shahina

Reputation: 128

Detect QApplication exit as normal or crash

I need to detect the application get exit as normal or crash. QProcess have the finished() signal and can get the exit code. But i need this exit code for QApplication when the application get crash or close.

Upvotes: 0

Views: 1641

Answers (2)

Kuba hasn't forgotten Monica
Kuba hasn't forgotten Monica

Reputation: 98425

When your process crashes, it's gone. The crash means that the process has finished because of an unhandled exception. Your job should be to prevent the crash from happening. In other words: handle the exceptions. Note that the exceptions may not be C++ exceptions, they may be low-level platform-specific mechanisms, such as native exceptions on Windows or signals on UNIX. You'd have to handle those, but recognize that the underlying issue is not fixed merely because you catch such an exception. You must assume that the state of your application has been corrupted, and the only safe thing to do is to exit ASAP anyway. For example, do not try to modify any files: you're likely to corrupt them.

Upvotes: 1

rbaleksandar
rbaleksandar

Reputation: 9691

I don't think this is something you can do just like that. Reading the value returned by QApplication::exec() is related to the Qt infrastructure:

Enters the main event loop and waits until exit() is called, then returns the value that was set to exit() (which is 0 if exit() is called via quit()).

Usually your main looks like this:

#include <QApplication>

int main( int argc, char **argv )
{
    QApplication a( argc, argv );

    // Initialize your widget(s)

    return a.exec(); // You can store this and check its value
}

However if I'm not mistaken this doesn't include handling a crash of your application (segmentation fault, unhandled exception etc.). In Linux people usually use a script which starts the application and then reads its exit code after the application quits or crashes. If you use Linux you can use echo $? to read the exit code from the bash scrip (or its equivalent for a different shell) and then do something based on its value.

Note also that you can at least do some exception handling since some crashes result in exactly that - an exception that has been thrown for some reason and has not been processed properly. Unhandled exceptions in Qt get propagated to the top level (that is QCoreApplication).

Upvotes: 0

Related Questions