segfault in qtfontdatabase_x11.cpp

[e8johan]

I'm trying to get Qt 4.1.1. to work in coLinux/debian. I've compiled a static version of Qt and I can run non-graphical applications. However, as soon as I try to run something graphical such as designer or assistant I get segfaults. To debug, I started out with this minimal application:

#include <QApplication>
#include <QMessageBox>
 
int main( int argc, char **argv )
{
	QApplication a( argc, argv );
 
	QMessageBox::information( 0, "", "Now it works!" );
 
	return 0;
}

#include <QApplication>
#include <QMessageBox>

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

	QMessageBox::information( 0, "", "Now it works!" );

	return 0;
}

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The application builds and work with the message box line commented out, but when I try to run it in the shape that it is above, I get the follow backtrace from gdb:

(gdb) run
Starting program: /home/johan/coding/testall/testall
[Thread debugging using libthread_db enabled]
[New Thread -1220707488 (LWP 481)]
Qt: gdb: -nograb added to command-line options.
        Use the -dograb option to enforce grabbing.
 
Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread -1220707488 (LWP 481)]
0xb7be83c5 in QFontDatabase::loadXlfd (screen=0, script=0,
   request=@0xbfffc890, force_encoding_id=-1) at qfontdatabase_x11.cpp:1678
1678    qfontdatabase_x11.cpp: No such file or directory.
       in qfontdatabase_x11.cpp
(gdb) bt
#0  0xb7be83c5 in QFontDatabase::loadXlfd (screen=0, script=0,
   request=@0xbfffc890, force_encoding_id=-1) at qfontdatabase_x11.cpp:1678
#1  0xb7be884a in QFontDatabase::load (d=0x806f968, script=0)
   at qfontdatabase_x11.cpp:1751
#2  0xb7b71fae in QFontPrivate::engineForScript (this=0x806f968, script=0)
   at qfont_p.h:155
#3  0xb7be3787 in QFontMetricsF::leading (this=0xbffff370)
   at text/qfontmetrics.cpp:1047
#4  0xb7b6e8c6 in qt_format_text (fnt=@0xbffff420, _r=@0xbffff430,
   tf=134236177, str=@0xbffff570, brect=0xbffff450, tabstops=0,
   tabarraylen=0, painter=0x0) at painting/qpainter.cpp:5527
#5  0xb7be2f57 in QFontMetrics::boundingRect (this=0xbffff550, r=@0xbffff4b0,
   flgs=2048, str=@0xbffff570, tabstops=0, tabarray=0x0)
   at text/qfontmetrics.cpp:688
#6  0xb7be301b in QFontMetrics::size (this=0xbffff550, flgs=2048,
   text=@0xbffff570, tabstops=0, tabarray=0x0) at text/qfontmetrics.cpp:720
#7  0xb7d95494 in QPushButton::sizeHint (this=0x8077778)
   at widgets/qpushbutton.cpp:379
#8  0xb7e29e77 in QMessageBox::resizeEvent (this=0xbffff830)
   at dialogs/qmessagebox.cpp:922
#9  0xb7ab54d8 in QWidget::event (this=0xbffff830, event=0xbffff7a0)
   at kernel/qwidget.cpp:5140
#10 0xb7e299c2 in QMessageBox::setButtonText (this=0xbffff830, button=1,
---Type <return> to continue, or q <return> to quit---
   text=@0xbffff820) at dialogs/qmessagebox.cpp:840
#11 0xb7e2ac63 in textBox (parent=0x0, severity=Information,
   caption=@0xbffff8f0, text=@0xbffff900, button0Text=@0xbffff910,
   button1Text=@0xbffff920, button2Text=@0xbffff930, defaultButtonNumber=0,
   escapeButtonNumber=-1) at dialogs/qmessagebox.cpp:1311
#12 0xb7e2adbe in QMessageBox::information (parent=0x0, caption=@0xbffff8f0,
   text=@0xbffff900, button0Text=@0xbffff910, button1Text=@0xbffff920,
   button2Text=@0xbffff930, defaultButtonNumber=0, escapeButtonNumber=-1)
   at dialogs/qmessagebox.cpp:1367
#13 0x08048abf in main (argc=1, argv=0xbffff9e4) at main.cpp:8

(gdb) run
Starting program: /home/johan/coding/testall/testall
[Thread debugging using libthread_db enabled]
[New Thread -1220707488 (LWP 481)]
Qt: gdb: -nograb added to command-line options.
        Use the -dograb option to enforce grabbing.

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread -1220707488 (LWP 481)]
0xb7be83c5 in QFontDatabase::loadXlfd (screen=0, script=0,
   request=@0xbfffc890, force_encoding_id=-1) at qfontdatabase_x11.cpp:1678
1678    qfontdatabase_x11.cpp: No such file or directory.
       in qfontdatabase_x11.cpp
(gdb) bt
#0  0xb7be83c5 in QFontDatabase::loadXlfd (screen=0, script=0,
   request=@0xbfffc890, force_encoding_id=-1) at qfontdatabase_x11.cpp:1678
#1  0xb7be884a in QFontDatabase::load (d=0x806f968, script=0)
   at qfontdatabase_x11.cpp:1751
#2  0xb7b71fae in QFontPrivate::engineForScript (this=0x806f968, script=0)
   at qfont_p.h:155
#3  0xb7be3787 in QFontMetricsF::leading (this=0xbffff370)
   at text/qfontmetrics.cpp:1047
#4  0xb7b6e8c6 in qt_format_text (fnt=@0xbffff420, _r=@0xbffff430,
   tf=134236177, str=@0xbffff570, brect=0xbffff450, tabstops=0,
   tabarraylen=0, painter=0x0) at painting/qpainter.cpp:5527
#5  0xb7be2f57 in QFontMetrics::boundingRect (this=0xbffff550, r=@0xbffff4b0,
   flgs=2048, str=@0xbffff570, tabstops=0, tabarray=0x0)
   at text/qfontmetrics.cpp:688
#6  0xb7be301b in QFontMetrics::size (this=0xbffff550, flgs=2048,
   text=@0xbffff570, tabstops=0, tabarray=0x0) at text/qfontmetrics.cpp:720
#7  0xb7d95494 in QPushButton::sizeHint (this=0x8077778)
   at widgets/qpushbutton.cpp:379
#8  0xb7e29e77 in QMessageBox::resizeEvent (this=0xbffff830)
   at dialogs/qmessagebox.cpp:922
#9  0xb7ab54d8 in QWidget::event (this=0xbffff830, event=0xbffff7a0)
   at kernel/qwidget.cpp:5140
#10 0xb7e299c2 in QMessageBox::setButtonText (this=0xbffff830, button=1,
---Type <return> to continue, or q <return> to quit---
   text=@0xbffff820) at dialogs/qmessagebox.cpp:840
#11 0xb7e2ac63 in textBox (parent=0x0, severity=Information,
   caption=@0xbffff8f0, text=@0xbffff900, button0Text=@0xbffff910,
   button1Text=@0xbffff920, button2Text=@0xbffff930, defaultButtonNumber=0,
   escapeButtonNumber=-1) at dialogs/qmessagebox.cpp:1311
#12 0xb7e2adbe in QMessageBox::information (parent=0x0, caption=@0xbffff8f0,
   text=@0xbffff900, button0Text=@0xbffff910, button1Text=@0xbffff920,
   button2Text=@0xbffff930, defaultButtonNumber=0, escapeButtonNumber=-1)
   at dialogs/qmessagebox.cpp:1367
#13 0x08048abf in main (argc=1, argv=0xbffff9e4) at main.cpp:8

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To me, it looks like it is desc.size->count that fails somehow:

...
       QList<int> encodings;
       if (desc.encoding)
           encodings.append(int(desc.encoding->encoding));
 
       // append all other encodings for the matched font
       for (int i = 0; i < desc.size->count; ++i) {
           QtFontEncoding *e = desc.size->encodings + i;
           if (e == desc.encoding)
               continue;
           encodings.append(int(e->encoding));
...

...
       QList<int> encodings;
       if (desc.encoding)
           encodings.append(int(desc.encoding->encoding));

       // append all other encodings for the matched font
       for (int i = 0; i < desc.size->count; ++i) {
           QtFontEncoding *e = desc.size->encodings + i;
           if (e == desc.encoding)
               continue;
           encodings.append(int(e->encoding));
...

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[jacek]

http://www.trolltech.com/developer/t...ntry&id=104979

[e8johan]

Thanks - I really need to learn to search the db.

[e8johan]

I've finally come around and build Qt 4.1.2. Now, the screen looks like this when I start Designer. Does anyone know what might be wrong? Am I missing a fonts package (running Debian)? Am I the only one running into this?