Updated code from 5.4 to 5.8 and dialog.exec(); gives seg fault
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Hi All,
I've updated from 5.4 to 5.8 and when I call one dialogue below it crashes on int ret = dialog.exec(); with a seg fault. Can anyone advise please?
Thanks[code]
QFileDialog dialog;dialog.setOptions(QFileDialog::DontUseNativeDialog ); // with or without this dialog.setFileMode(QFileDialog::AnyFile); dialog.setAcceptMode(QFileDialog::AcceptSave); /*set the directory*/ if( get_gamepath().isEmpty( ) ) { dialog.setDirectory("."); } else { dialog.setDirectory( get_gamepath( ) ); } dialog.selectFile( name ); // magic happens here dialog.setNameFilter("*.xml"); QStringList filters; filters << "Game files (*.xml)"; dialog.setNameFilters( filters ); int ret = dialog.exec(); if (ret == QDialog::Accepted) { qDebug() << dialog.selectedFiles(); gamefilename = dialog.selectedFiles().at( 0 ); }[/code]
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Hi,
Can you show a stack trace of this crash ?
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Hi,
the stack is below.
Thanks.[code]
1 ?? 0x7fffed985d16
2 ?? 0x7fffed98a44a
3 ?? 0x7fffed00e3c3
4 ?? 0x7fffed00e3f9
5 g_main_context_dispatch 0x7ffff23c4b4d
6 ?? 0x7ffff23c4f20
7 g_main_context_iteration 0x7ffff23c4fcc
8 QEventDispatcherGlib::processEvents(QFlagsQEventLoop::ProcessEventsFlag) 0x7ffff63bccbf
9 QEventLoop::exec(QFlagsQEventLoop::ProcessEventsFlag) 0x7ffff636a9ca
10 QDialog::exec() 0x7ffff7664a07
11 Main_Class::save_the_game main_class.cpp 79 0x488c25
12 GameSimulation_PerfectGame_Dialog::GameSimulation_PerfectGame_Dialog gamesimulation_perfectgame_dialog.cpp 39 0x492d20
13 MainWindow::on_actionFPerfect_Game_Simulation_triggered mainwindow.cpp 622 0x4163cb
14 MainWindow::qt_static_metacall moc_mainwindow.cpp 193 0x59c480
15 MainWindow::qt_metacall moc_mainwindow.cpp 232 0x59c5da
16 QMetaObject::activate(QObject *, int, int, void * *) 0x7ffff6395564
17 QAction::triggered(bool) 0x7ffff7486cb2
18 QAction::activate(QAction::ActionEvent) 0x7ffff7489150
19 ?? 0x7ffff75e972a
20 ?? 0x7ffff75f0656
... <More>
[/code]The function that causes the crash "int ret = dialog.exec();" is called in 11 Main_Class::save_the_game
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Running on Linux ? If so, which distribution ?
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Hi, some questions:
- What happens if you use
QFileDialog::getSaveFileName()instead of creating a custom dialog? http://doc.qt.io/qt-5/qfiledialog.html#getSaveFileName - Is your program doing anything else in the background when you open the dialog?
- What happens if you use
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Hi ,
there's no threads running in the back ground. I tried getSaveFileName but get an error?gamefilename = dialog.getSaveFileName( this, tr("Save File"), "game.xml", tr("Game files (*.xml)"));error
/home/tony/Dropbox/NewDevelopment/Tools/Game/main_class.cpp:92: error: no matching function for call to ‘QFileDialog::getSaveFileName(Main_Class*, QString, const char [9], QString)’ tr("Game files (*.xml)")); ^ /home/tony/Qt/5.8/gcc_64/include/QtWidgets/qfiledialog.h:225: static QString QFileDialog::getSaveFileName(QWidget*, const QString&, const QString&, const QString&, QString*, QFileDialog::Options) static QString getSaveFileName(QWidget *parent = Q_NULLPTR, ^even if I copy and paste the example I get the error
egQString fileName = QFileDialog::getSaveFileName(this, tr("Save File"), "/home/jana/untitled.png", tr("Images (*.png *.xpm *.jpg)"));error
/home/tony/Dropbox/NewDevelopment/Tools/Game/main_class.cpp:92: error: no matching function for call to ‘QFileDialog::getSaveFileName(Main_Class*, QString, const char [24], QString)’ tr("Images (*.png *.xpm *.jpg)")); ^ /home/tony/Qt/5.8/gcc_64/include/QtWidgets/qfiledialog.h:225: static QString QFileDialog::getSaveFileName(QWidget*, const QString&, const QString&, const QString&, QString*, QFileDialog::Options) static QString getSaveFileName(QWidget *parent = Q_NULLPTR, ^ -
Looks like Main_Class is not QWidget based.
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Hi, My main is a qObject, would this cause the crash in dialog.exec? Or is this just related to getSaveFileName?
class Main_Class : public QObject { Q_OBJECT public: explicit Main_Class(QObject *parent = 0); void set_name( QString name ); QString get_name( void ); -
Hi, My main is a qObject, would this cause the crash in dialog.exec? Or is this just related to getSaveFileName?
class Main_Class : public QObject { Q_OBJECT public: explicit Main_Class(QObject *parent = 0); void set_name( QString name ); QString get_name( void );@tony67 said in Updated code from 5.4 to 5.8 and dialog.exec(); gives seg fault:
Or is this just related to getSaveFileName?
In the example code,
thisis the parent widget. If you don't have a parent widget, just pass anullptr. -
Hi, My main is a qObject, would this cause the crash in dialog.exec? Or is this just related to getSaveFileName?
class Main_Class : public QObject { Q_OBJECT public: explicit Main_Class(QObject *parent = 0); void set_name( QString name ); QString get_name( void );Yep,
getSaveFileName(QWidget *parent = Q_NULLPTR, const QString &caption = QString(), const QString &dir = QString(), const QString &filter = QString(), QString *selectedFilter = Q_NULLPTR, Options options = Options())Usually QWidgets inherit QObject, but not the other way around.
Either give it a QWidget as parent or, do it as @JKSH said, and give it no parent.
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Hi,
did the above with parent, still get the seg faultgamefilename = dialog.getSaveFileName( nullptr, tr("Save File"), "game.xml", tr("Game files (*.xml)"));fault
1 ?? 0x7fffed985d16 2 ?? 0x7fffed98a44a 3 ?? 0x7fffed00e3c3 4 ?? 0x7fffed00e3f9 5 g_main_context_dispatch 0x7ffff23c4b4d 6 ?? 0x7ffff23c4f20 7 g_main_loop_run 0x7ffff23c5242 8 gtk_dialog_run 0x7fffed95d6a0 9 ?? 0x7fffee0cd73a 10 QDialog::exec() 0x7ffff766492a 11 QFileDialog::getSaveFileUrl(QWidget *, QString const&, QUrl const&, QString const&, QString *, QFlags<QFileDialog::Option>, QStringList const&) 0x7ffff7675ecd 12 QFileDialog::getSaveFileName(QWidget *, QString const&, QString const&, QString const&, QString *, QFlags<QFileDialog::Option>) 0x7ffff7675f8a 13 Main_Class::save_the_game main_class.cpp 90 0x488d53 14 GameSimulation_PerfectGame_Dialog::GameSimulation_PerfectGame_Dialog gamesimulation_perfectgame_dialog.cpp 39 0x492d66 15 MainWindow::on_actionFPerfect_Game_Simulation_triggered mainwindow.cpp 622 0x41646b 16 MainWindow::qt_static_metacall moc_mainwindow.cpp 193 0x59c4c6 17 MainWindow::qt_metacall moc_mainwindow.cpp 232 0x59c620 18 QMetaObject::activate(QObject *, int, int, void * *) 0x7ffff6395564 19 QAction::triggered(bool) 0x7ffff7486cb2 20 QAction::activate(QAction::ActionEvent) 0x7ffff7489150 ... <More> -
Might be something Ubuntu 14.04 related. This other thread seems to have a similar crash.
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Sounds interesting, can you re-build and test your application with your distribution provided Qt development environment ?
