Including 3rd party software makes my program crash with QFileDialog

[wysota]

Could we focus on the minimal example please?
Compile this one and see if it crashes on you. If it does, provide a backtrace and ldd of the program and libQtCore.so

#include <QtGui>
 
int main(int argc, char **argv){
  QApplication app(argc, argv);
  QFileDialog::getOpenFileName();
  return 0;
}

#include <QtGui>

int main(int argc, char **argv){
  QApplication app(argc, argv);
  QFileDialog::getOpenFileName();
  return 0;
}

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and this project file:

TEMPLATE=app
SOURCES += main.cpp
LIBS += -L/opt/halcon/lib/x64-linux2.4-gcc40 -lhalcon -lhalconcpp

TEMPLATE=app
SOURCES += main.cpp
LIBS += -L/opt/halcon/lib/x64-linux2.4-gcc40 -lhalcon -lhalconcpp

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And please post the result of "gcc -v" and "uname -rm" on your system.

[ruben.rodrigues]

Could we focus on the minimal example please?
Compile this one and see if it crashes on you. If it does, provide a backtrace and ldd of the program and libQtCore.so

#include <QtGui>
 
int main(int argc, char **argv){
  QApplication app(argc, argv);
  QFileDialog::getOpenFileName();
  return 0;
}

#include <QtGui>

int main(int argc, char **argv){
  QApplication app(argc, argv);
  QFileDialog::getOpenFileName();
  return 0;
}

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and this project file:

TEMPLATE=app
SOURCES += main.cpp
LIBS += -L/opt/halcon/lib/x64-linux2.4-gcc40 -lhalcon -lhalconcpp

TEMPLATE=app
SOURCES += main.cpp
LIBS += -L/opt/halcon/lib/x64-linux2.4-gcc40 -lhalcon -lhalconcpp

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And please post the result of "gcc -v" and "uname -rm" on your system.

main.cpp:

#include <QtGui>
 
int main(int argc, char **argv){
   QApplication app(argc, argv);
   QFileDialog::getOpenFileName();
   return 0;
}

#include <QtGui>

int main(int argc, char **argv){
   QApplication app(argc, argv);
   QFileDialog::getOpenFileName();
   return 0;
}

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pro file:

TEMPLATE = app
TARGET = filedialog_test 
QT        += core 
SOURCES   += main.cpp
LIBS += -L/opt/halcon/lib/x64-linux2.4-gcc40 -lhalcon -lhalconcpp

TEMPLATE = app
TARGET = filedialog_test 
QT        += core 
SOURCES   += main.cpp
LIBS += -L/opt/halcon/lib/x64-linux2.4-gcc40 -lhalcon -lhalconcpp

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gcc version 4.3.3 (Ubuntu 4.3.3-5ubuntu4)
2.6.28-19-generic x86_64

backtrace as attachment.

thank you!

[wysota]

I don't think we will solve this here. The crash is deep inside Gnome's libraries. If you ran your app in KDE, it would probably work. I can only suggest a workaround - pass DontUseNativeDialog option to QFileDialog. You will then get Qt's own file dialog instead of the one native to your desktop and with a bit of luck it will not crash. Unless it is libpng which causes the crash. You either have a misconfiguration in your system or these halon libs are really messed up. With a bit of bad luck it is probable that every call to libpng will end up with a crash.

[ruben.rodrigues]

I don't think we will solve this here. The crash is deep inside Gnome's libraries. If you ran your app in KDE, it would probably work. I can only suggest a workaround - pass DontUseNativeDialog option to QFileDialog. You will then get Qt's own file dialog instead of the one native to your desktop and with a bit of luck it will not crash. Unless it is libpng which causes the crash. You either have a misconfiguration in your system or these halon libs are really messed up. With a bit of bad luck it is probable that every call to libpng will end up with a crash.

Hey! It works if I use the option DontUseNativeDialog. I am still figuring out how to get the value of the search because I just tested like this:

QFileDialog dlg(this);
dlg.setOption(QFileDialog:ontUseNativeDialog, false);
dlg.exec();

If I do this:

QString fileName = QFileDialog::getOpenFileName(this, tr("OpenFile: "),"/home/rrodrigues/Desktop",QFileDialog:ontUseNativeDialog);

or

QString fileName = QFileDialog::getOpenFileName(this, tr("OpenFile: "),QString("/home/rrodrigues/Desktop"),QFileDialog:ontUseNativeDialog);

it tell me no matching function:

no matching function for call to ‘QFileDialog::getOpenFileName(ldiclient* const, QString, const char [25], QFileDialog::Option)’
no matching function for call to ‘QFileDialog::getOpenFileName(ldiclient* const, QString, QString, QFileDialog::Option)’

I am already very happy that I can see the dialog but can you tell me what is wrong with the function?

[wysota]

Look at the available variants of getOpenFileName(), the Options argument is the last one so you have to explicitly pass all the previous ones.

[ruben.rodrigues]

I tried like this but it doesn't work: (it terminates like it used before)

QFileDialog dlg(this);
dlg.setOption(QFileDialog::DontUseNativeDialog, false);
QString test = dlg.getOpenFileName();
dlg.exec();
cout << test.toStdString() << endl;

If I do it like this it works but I can't get the file name:

QFileDialog dlg(this);
dlg.setOption(QFileDialog::DontUseNativeDialog, false);
dlg.exec();

[wysota]

QString fileName = QFileDialog::getOpenFileName(this, tr("Open File"),
                                                 "/home",
                                                 tr("Images (*.png *.xpm *.jpg)"), 0, QFileDialog::DontUseNativeDialog);

QString fileName = QFileDialog::getOpenFileName(this, tr("Open File"),
                                                 "/home",
                                                 tr("Images (*.png *.xpm *.jpg)"), 0, QFileDialog::DontUseNativeDialog);

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or

QFileDialog dlg(this); // you don't need to set DontUseNativeDialog here
QStringList selectedFiles;
if(dlg.exec()){   
  selectedFiles = dlg.selectedFiles();
}

QFileDialog dlg(this); // you don't need to set DontUseNativeDialog here
QStringList selectedFiles;
if(dlg.exec()){   
  selectedFiles = dlg.selectedFiles();
}

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[ruben.rodrigues]

QString fileName = QFileDialog::getOpenFileName(this, tr("Open File"),
                                                 "/home",
                                                 tr("Images (*.png *.xpm *.jpg)"), 0, QFileDialog::DontUseNativeDialog);

QString fileName = QFileDialog::getOpenFileName(this, tr("Open File"),
                                                 "/home",
                                                 tr("Images (*.png *.xpm *.jpg)"), 0, QFileDialog::DontUseNativeDialog);

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or

QFileDialog dlg(this); // you don't need to set DontUseNativeDialog here
QStringList selectedFiles;
if(dlg.exec()){   
  selectedFiles = dlg.selectedFiles();
}

QFileDialog dlg(this); // you don't need to set DontUseNativeDialog here
QStringList selectedFiles;
if(dlg.exec()){   
  selectedFiles = dlg.selectedFiles();
}

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Thanks a lot man! it works like a charm now. it was kind of a weird error but good thing that qt has this DontUseNativeDialog thing.

Also sorry for the delay but I was busy with other parts of the project.