Valgrind ungültiger Lese- und Segmentierungsfehler mit QApplication

Question

Ich bin mit Laufzeitfehlern in meiner Qt-Anwendung festgefahren. Dies ist Teil meiner Valgrind-Ausgabe. Es gibt mehr davor, aber es ist viel zu posten.

==13659== Invalid read of size 8 
==13659== at 0x75E4085: QCoreApplication::arguments() (in /usr/local/Qt/5.2.1/gcc_64/lib/libQt5Core.so.5.2.1) 
==13659== by 0x1B4E0114: ??? (in /usr/local/Qt/5.2.1/gcc_64/plugins/platforms/libqxcb.so) 
==13659== by 0x1B4E10E8: ??? (in /usr/local/Qt/5.2.1/gcc_64/plugins/platforms/libqxcb.so) 
==13659== by 0x1B9C0D2E: _SmcProcessMessage (in /usr/lib/x86_64-linux-gnu/libSM.so.6.0.1) 
==13659== by 0x1BBD48A5: IceProcessMessages (in /usr/lib/x86_64-linux-gnu/libICE.so.6.3.0) 
==13659== by 0x76096B0: QMetaObject::activate(QObject*, int, int, void**) (in /usr/local/Qt/5.2.1/gcc_64/lib/libQt5Core.so.5.2.1) 
==13659== by 0x767B1FD: QSocketNotifier::activated(int, QSocketNotifier::QPrivateSignal) (in /usr/local/Qt/5.2.1/gcc_64/lib/libQt5Core.so.5.2.1) 
==13659== by 0x7616840: QSocketNotifier::event(QEvent*) (in /usr/local/Qt/5.2.1/gcc_64/lib/libQt5Core.so.5.2.1) 
==13659== by 0x65D20F3: QApplicationPrivate::notify_helper(QObject*, QEvent*) (in /usr/local/Qt/5.2.1/gcc_64/lib/libQt5Widgets.so.5.2.1) 
==13659== by 0x65D56AD: QApplication::notify(QObject*, QEvent*) (in /usr/local/Qt/5.2.1/gcc_64/lib/libQt5Widgets.so.5.2.1) 
==13659== by 0x75E0733: QCoreApplication::notifyInternal(QObject*, QEvent*) (in /usr/local/Qt/5.2.1/gcc_64/lib/libQt5Core.so.5.2.1) 
==13659== by 0x7630A55: ??? (in /usr/local/Qt/5.2.1/gcc_64/lib/libQt5Core.so.5.2.1) 
==13659== Address 0x178ddfb0 is 0 bytes after a block of size 16 alloc'd 
==13659== at 0x4C28147: operator new[](unsigned long) (vg_replace_malloc.c:348) 
==13659== by 0x4FAD41: GUIApp::init() (GUIApp.cpp:73) 
==13659== by 0x423009: main (main.cpp:121) 
==13659== 
==13659== Invalid read of size 1 
==13659== at 0x4C294E2: strlen (mc_replace_strmem.c:390) 
==13659== by 0x75E409B: QCoreApplication::arguments() (in /usr/local/Qt/5.2.1/gcc_64/lib/libQt5Core.so.5.2.1) 
==13659== by 0x1B4E0114: ??? (in /usr/local/Qt/5.2.1/gcc_64/plugins/platforms/libqxcb.so) 
==13659== by 0x1B4E10E8: ??? (in /usr/local/Qt/5.2.1/gcc_64/plugins/platforms/libqxcb.so) 
==13659== by 0x1B9C0D2E: _SmcProcessMessage (in /usr/lib/x86_64-linux-gnu/libSM.so.6.0.1) 
==13659== by 0x1BBD48A5: IceProcessMessages (in /usr/lib/x86_64-linux-gnu/libICE.so.6.3.0) 
==13659== by 0x76096B0: QMetaObject::activate(QObject*, int, int, void**) (in /usr/local/Qt/5.2.1/gcc_64/lib/libQt5Core.so.5.2.1) 
==13659== by 0x767B1FD: QSocketNotifier::activated(int, QSocketNotifier::QPrivateSignal) (in /usr/local/Qt/5.2.1/gcc_64/lib/libQt5Core.so.5.2.1) 
==13659== by 0x7616840: QSocketNotifier::event(QEvent*) (in /usr/local/Qt/5.2.1/gcc_64/lib/libQt5Core.so.5.2.1) 
==13659== by 0x65D20F3: QApplicationPrivate::notify_helper(QObject*, QEvent*) (in /usr/local/Qt/5.2.1/gcc_64/lib/libQt5Widgets.so.5.2.1) 
==13659== by 0x65D56AD: QApplication::notify(QObject*, QEvent*) (in /usr/local/Qt/5.2.1/gcc_64/lib/libQt5Widgets.so.5.2.1) 
==13659== by 0x75E0733: QCoreApplication::notifyInternal(QObject*, QEvent*) (in /usr/local/Qt/5.2.1/gcc_64/lib/libQt5Core.so.5.2.1) 
==13659== Address 0x50 is not stack'd, malloc'd or (recently) free'd 
==13659== 
==13659== 
==13659== Process terminating with default action of signal 11 (SIGSEGV) 
==13659== Access not within mapped region at address 0x50 
==13659== at 0x4C294E2: strlen (mc_replace_strmem.c:390) 
==13659== by 0x75E409B: QCoreApplication::arguments() (in /usr/local/Qt/5.2.1/gcc_64/lib/libQt5Core.so.5.2.1) 
==13659== by 0x1B4E0114: ??? (in /usr/local/Qt/5.2.1/gcc_64/plugins/platforms/libqxcb.so) 
==13659== by 0x1B4E10E8: ??? (in /usr/local/Qt/5.2.1/gcc_64/plugins/platforms/libqxcb.so) 
==13659== by 0x1B9C0D2E: _SmcProcessMessage (in /usr/lib/x86_64-linux-gnu/libSM.so.6.0.1) 
==13659== by 0x1BBD48A5: IceProcessMessages (in /usr/lib/x86_64-linux-gnu/libICE.so.6.3.0) 
==13659== by 0x76096B0: QMetaObject::activate(QObject*, int, int, void**) (in /usr/local/Qt/5.2.1/gcc_64/lib/libQt5Core.so.5.2.1) 
==13659== by 0x767B1FD: QSocketNotifier::activated(int, QSocketNotifier::QPrivateSignal) (in /usr/local/Qt/5.2.1/gcc_64/lib/libQt5Core.so.5.2.1) 
==13659== by 0x7616840: QSocketNotifier::event(QEvent*) (in /usr/local/Qt/5.2.1/gcc_64/lib/libQt5Core.so.5.2.1) 
==13659== by 0x65D20F3: QApplicationPrivate::notify_helper(QObject*, QEvent*) (in /usr/local/Qt/5.2.1/gcc_64/lib/libQt5Widgets.so.5.2.1) 
==13659== by 0x65D56AD: QApplication::notify(QObject*, QEvent*) (in /usr/local/Qt/5.2.1/gcc_64/lib/libQt5Widgets.so.5.2.1) 
==13659== by 0x75E0733: QCoreApplication::notifyInternal(QObject*, QEvent*) (in /usr/local/Qt/5.2.1/gcc_64/lib/libQt5Core.so.5.2.1) 
==13659== If you believe this happened as a result of a stack 
==13659== overflow in your program's main thread (unlikely but 
==13659== possible), you can try to increase the size of the 
==13659== main thread stack using the --main-stacksize= flag. 
==13659== The main thread stack size used in this run was 8388608. 

Ich bin porting code Qt3 to Qt5 and from 32-bit to 64-bit. Linie 73 in meinem Code ist unter test = new char*[2];.

Mein Programm scheint mit Segmentierung Fehler auf dem showFullScreen() Anruf abstürzen.

Könnte die Verwendung der Variablen test die Ursache der Valgrind-Ausgabe und des Programmabsturzes sein? Ist die Form von Argc und Argv auf 64-Bit-Linux die gleiche wie 32-Bit?

void GUIApp::init() 
{ 
    QApplication::setStyle("motif"); 

    int nbrparams=1; 
    test = new char*[2]; 
    test[0] = new char[100]; 
    test[1] = new char[100]; 
     printf(" Test : %d\n", (int)sizeof test);  // Test : 8 
     printf(" *Test : %d\n", (int)sizeof *test); // *Test : 8 
     printf("**Test : %d\n", (int)sizeof **test); // **Test : 1 
    strcpy(test[0], "gv_GUI"); 

    go_app = new QApplication(nbrparams,test); 

    translator = new QTranslator(0); 
    // load translation file, make sure that this symbolic link points to the desired translation file 
    if (translator->load("tt2_go.qm")) { 
     go_app->installTranslator(translator); 
    } 

    gaw = new GO_QT_Application_Widget(GO_GUI_MODE, mytalkbackptr, NULL, "QTApp"); 
    gaw->init(); 
    gaw->startup(); 

    gaw->move(0,0); 
    gaw->setFixedSize(3200,1200); 
    gaw->showFullScreen(); 

    init_done = true; 
} 

Answer 1

Zuerst wird das argv Array sollte einen NULL-Zeiger nach dem letzten gültigen Argumente haben, so dass argv[argc] immer NULL ist. So ist die minimale Einstellung, die Ihren Code beheben sollte, wäre

test[1] = NULL; /* instead of test[1] = new char[100]; */ 

Zweitens sehe ich nicht den Punkt der new auf die Argumente zu tun, da Sie immer sie gültig sein soll. Vielleicht gibt es einen Vorteil darin, den ich nicht sehe (Ich habe C Hintergrund, weißt du), aber unten ist der Code, den ich dafür geschrieben hätte. Das funktioniert.

char * progName = "myProg"; 
char * arg1 = "-n"; 
char * arg2 = "10"; 

char *test[] = { 
    progName, 
    arg1, 
    arg2, 
    NULL 
}; 

int nbrparams=3; 

go_app = new QApplication(nbrparams, test);