Qt app crash on mac when executed with parameters

Our reporting tool occasional crashed on MacOs when was executed with several command line params. Command looked like this:

/app-path/OrmDesigner2 -crash-report -dump-directory /var/folders/4z/k1r35jnn4v77mzl7hzf8wvvw0000gn/T/OrmDesigner2/CrashReports

When inspecting exception report, we found following stack trace:

Thread 0 Crashed:  Dispatch queue: com.apple.main-thread
0   QtCore                         0x0000000100d671da QString::fromLocal8Bit(char const*, int) + 42
1   QtCore                         0x0000000100e72dac QCoreApplication::arguments() + 124
2   QtGui                          0x00000001000de8ef -[QCocoaApplicationDelegate application:openFiles:] + 223
3   com.apple.AppKit               0x00007fff805f3b52 -[NSApplication(NSAppleEventHandling) _handleAEOpenDocumentsForURLs:] + 505
4   com.apple.AppKit               0x00007fff804c0065 -[NSApplication(NSAppleEventHandling) _handleCoreEvent:withReplyEvent:] + 217
5   com.apple.Foundation           0x00007fff800f90d6 -[NSAppleEventManager dispatchRawAppleEvent:withRawReply:handlerRefCon:] + 360
6   com.apple.Foundation           0x00007fff800f8f06 _NSAppleEventManagerGenericHandler + 114
7   com.apple.AE                   0x00007fff82b1c32b aeDispatchAppleEvent(AEDesc const*, AEDesc*, unsigned int, unsigned char*) + 162
8   com.apple.AE                   0x00007fff82b1c224 dispatchEventAndSendReply(AEDesc const*, AEDesc*) + 32
9   com.apple.AE                   0x00007fff82b1c12b aeProcessAppleEvent + 210
10  com.apple.HIToolbox            0x00007fff875ed619 AEProcessAppleEvent + 48
11  com.apple.AppKit               0x00007fff803c5095 _DPSNextEvent + 1191
12  com.apple.AppKit               0x00007fff803c4801 -[NSApplication nextEventMatchingMask:untilDate:inMode:dequeue:] + 155
13  com.apple.AppKit               0x00007fff8038a68f -[NSApplication run] + 395
14  QtGui                          0x00000001000e7c04 QEventDispatcherMac::processEvents(QFlags) + 1588
15  QtCore                         0x0000000100e70774 QEventLoop::processEvents(QFlags) + 68
16  QtCore                         0x0000000100e70a94 QEventLoop::exec(QFlags) + 180
17  QtCore                         0x0000000100e720bc QCoreApplication::exec() + 188
18  com.inventic.ormdesigner       0x0000000100003447 main + 46 (main.cpp:31)
19  com.inventic.ormdesigner       0x00000001000032e0 start + 52

After some google-searching I found out that the problem is in core of our application. When subclassing Qt QApplication, it’s necessary to pass argc with reference, not by value. So after adding one little &, everything works like charm!

//construct application object
CApplication(int& argc, char **argv);

External links

• http://qt-project.org/forums/viewthread/18703/