启动时Qt Designer和Qt Assistant seg错误

Question

I apologize if this is in the wrong section - move as necessary...

A bit of background: I have a Qt 4.8.4 application that I've built that runs beautifully...for me. I'm connected to a Linux Redhat box using VNC.

However, when giving the application to a colleague for use, he is unable to make it run without getting a segmentation fault: basically, he'll try to check one of the checkboxes, and the application will seg fault and using gdb, the backtrace shows:

#0  0x00000000 in ?? ()
#1  0xb7a2b9e8 in QGtkStyle::drawComplexControl () from /usr/local/Trolltech/Qt-4.8.4/lib/libQtGui.so.4
#2  0xb7b315b5 in QScrollBar::paintEvent () from /usr/local/Trolltech/Qt-4.8.4/lib/libQtGui.so.4
#3  0xb7682fd4 in QWidget::event () from /usr/local/Trolltech/Qt-4.8.4/lib/libQtGui.so.4
...

Couple of things to note:

1. The other user: he's on the SAME Linux Redhat box as I am, just a different login. He has EXACTLY the same PATH , QTDIR , QTLIB , QTBIN , QTINC , & QTMAKESPEC as I do. We are both using the bash shell.
2. I put a bit of debug in my application to compare the system environment as known by qt, and those are the same (with the execption of user name/login stuff).

I've been banging my head on my desk trying to figure this out.

Well, I decided to do something random, & I ran the Qt Designer which is installed...It failed to start. Interesting...

So I did some investigating and found that the Qt Designer in the menu is for Qt-3.3, which is also installed. That, or so I've read, should not be an issue.

I then tried to launch the Qt Designer that was packaged with Qt 4.8.4 and surprise surprise but it too fails to start. If I try to start it from a terminal, I get a "Segmentation Fault" output. (Further investigation shows that the Qt Assistant is doing the same thing...)

Running designer (for qt 4.8.4) through gdb, the backtrace shows:

#0  0x00000000 in ?? ()
#1  0xb6f049e8 in QGtkStyle::drawComplexControl() from /usr/local/Trolltech/Qt-4.8.4/lib/libQtGui.so.4
#2  0xb700a5b5 in QScrollBar::paintEvent() from /usr/local/Trolltech/Qt-4.8.4/lib/libQtGui.so.4
#3  0xb6b5bfd4 in QWidget::event () from /usr/local/Trolltech/Qt-4.8.4/lib/libQtGui.so.4

THE BACKTRACE FOR THE DESIGNER IS THE SAME AS THE BACKTRACE FOR MY APPLICATION!

...and I don't know what that means for my application/other user.

I originally thought of reinstalling Qt, but how would that fix things if it's working fine for me?

Answer 1

So for anyone who is having a similiar issue, I believe I have found the answer, well at least in this case:

After comparing my home directory and the other user's home directory, I found two folders that peaked my interest:

.config/
.qt/

As it turns out, the other user was missing the .qt folder! AND inside my .config, I had a "Trolltech" folder which he did not have. So I copied mine to his and noticed one final thing before trying to run things again...

Under .config/, there is a file called Trolltech.conf - well guess what: his was drastically different from mine: it wasn't setting everything for Qt 4.8.4 that my Trolltech.conf file was setting. So I copied that too.

And lo-and-behold - Qt Designer (for 3.3 and 4.8.4), Qt Assistant, AND my application all work beautifully now. :D