问题
How should I quit a Qt Program, e.g when loading a data file, and discovered file corruption, and user need to quit this app or re-initiate data file?
Should I:
- call
exit(EXIT_FAILURE) - call
QApplication::quit() - call
QCoreApplication::quit()
And difference between (2) and (3)?
回答1:
QApplication is derived from QCoreApplication and thereby inherits quit() which is a public slot of QCoreApplication, so there is no difference between QApplication::quit() and QCoreApplication::quit().
As we can read in the documentation of QCoreApplication::quit() it "tells the application to exit with return code 0 (success).". If you want to exit because you discovered file corruption then you may not want to exit with return code zero which means success, so you should call QCoreApplication::exit() because you can provide a non-zero returnCode which, by convention, indicates an error.
It is important to note that "if the event loop is not running, this function (QCoreApplication::exit()) does nothing", so in that case you should call exit(EXIT_FAILURE).
回答2:
You can call qApp.exit();. I always use that and never had a problem with it.
If you application is a command line application, you might indeed want to return an exit code. It's completely up to you what the code is.
回答3:
If you're using Qt Jambi, this should work:
QApplication.closeAllWindows();
回答4:
if you need to close your application from main() you can use this code
int main(int argc, char *argv[]){
QApplication app(argc, argv);
...
if(!QSslSocket::supportsSsl()) return app.exit(0);
...
return app.exec();
}
The program will terminated if OpenSSL is not installed
回答5:
//How to Run App
bool ok = QProcess::startDetached("C:\\TTEC\\CozxyLogger\\CozxyLogger.exe");
qDebug() << "Run = " << ok;
//How to Kill App
system("taskkill /im CozxyLogger.exe /f");
qDebug() << "Close";
example
来源：https://stackoverflow.com/questions/8026101/correct-way-to-quit-a-qt-program