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Thread: segfault

  1. 31st May 2006, 11:59 #1
    conexion2000
    conexion2000 is offline Novice
    Join Date
    Mar 2006
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    4

    Default segfault

    Hello!
    I have got a class SmsGui which contains 2 forms generated by qtdesigner: mainWindow and loginWindow. Firstly when program runs, mainWidnow is created and shown. When user presses Ok on mainWindow, loginWindow is created and shown. And here are 2 situations: in first situation I do:
    Qt Code: 
    1. connect(loginWindow->cancelButton, SIGNAL(clicked()), loginWindow, SLOT(close()));
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    And loginDialog closes normally. But in a secod situation I call loginDialog->close() manually.
    Qt Code: 
    1. connect(loginWindow->cancelButton, SIGNAL(clicked()), this, SLOT(kill()));
    2.  
    3. void SmsGui::kill()
    4. {
    5. 	loginDialog->close();
    6. }
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    And this gives me a segfault. Why? I just call the same function but in 2 different ways, so why it gives me a segfault?
    Backtrace:
    Qt Code: 
    1. Program received signal SIGSEGV, Segmentation fault.
    2. [Switching to Thread -1223948608 (LWP 25558)]
    3. 0x0804d9a4 in SmsGui::kill (this=0x8061670) at sms_gui.cpp:125
    4. 125             loginDialog->close();
    5. (gdb) backtrace
    6. #0  0x0804d9a4 in SmsGui::kill (this=0x8061670)
    7.     at sms_gui.cpp:125
    8.  
    9. #1  0x0804d995 in SmsGui::clickedLoginOk (this=0x8061670)
    10.     at sms_gui.cpp:120
    11. #2  0x08050d14 in SmsGui::qt_metacall (this=0x8061670, 
    12.     _c=QMetaObject::InvokeMetaMethod, _id=5, _a=0xbfa59790)
    13.     at moc_sms_gui.cpp:83
    14. #3  0xb746132c in QMetaObject::activate ()
    15.    from /usr/lib/qt4/libQtCore_debug.so.4
    16. #4  0xb746157e in QMetaObject::activate ()
    17.    from /usr/lib/qt4/libQtCore_debug.so.4
    18. #5  0xb7e011f6 in QAbstractButton::clicked ()
    19.    from /usr/lib/qt4/libQtGui_debug.so.4
    20. #6  0xb7c66455 in QAbstractButtonPrivate::click ()
    21.    from /usr/lib/qt4/libQtGui_debug.so.4
    22. #7  0xb7c67779 in QAbstractButton::mouseReleaseEvent ()
    23.    from /usr/lib/qt4/libQtGui_debug.so.4
    24. #8  0xb7a3879d in QWidget::event ()
    25.    from /usr/lib/qt4/libQtGui_debug.so.4
    26. #9  0xb7c6761b in QAbstractButton::event ()
    27.    from /usr/lib/qt4/libQtGui_debug.so.4
    28. #10 0xb7ce0d52 in QPushButton::event ()
    29.    from /usr/lib/qt4/libQtGui_debug.so.4
    30. #11 0xb79ecea7 in QApplicationPrivate::notify_helper ()
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    Header file:
    Qt Code: 
    1. #ifndef SMS_GUI_H
    2. #define SMS_GUI_H
    3.  
    4. #include <QDialog>
    5. #include "ui_main_window.h"
    6. #include "ui_login_dialog.h"
    7. #include "types.h"
    8.  
    9. class SmsGui : public QObject
    10.  
    11. {
    12.  
    13. 	Q_OBJECT
    14.  
    15. 	public:
    16. 		QString username, password, number, message;
    17. 		bool limitCheck;
    18. 		unsigned short int port;
    19. 		void destroy();
    20. 		void showMainWindow();
    21.  
    22. 		void connectSlots();
    23. 		void disconnectSlots();
    24. 		void setMiastoPlusaParameters();
    25. 		void showLoginDialog();
    26. 		Ui_mainWindow *mainWindow;
    27. 		QDialog *mainDialog;
    28.  
    29. 		Ui_loginDialog *loginWindow;
    30. 		QDialog *loginDialog;
    31.  
    32.  
    33.  
    34. 	public slots:
    35. 		void enableSendButtonText();
    36. 		void enableSendButtonLine(const QString &newText);
    37. 		void resetAll();
    38. 		void currentIndexChanged(int index);
    39. 		void clickedLoginOk();
    40. 		void clickedSend();
    41. 		void clickedLoginCancel();
    42.  
    43. 		void closeMainWindow();
    44. 		void kill();
    45. 	public:
    46. 		SmsGui();
    47. 		~SmsGui();
    48.  
    49. 	signals:
    50. 		void readyToSend(network);
    51.  
    52.  
    53. };
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    source:
    Qt Code: 
    1. #include "sms_gui.h"
    2.  
    3. SmsGui::SmsGui()
    4. {
    5. 	showMainWindow();
    6. 	connectSlots();
    7. }
    8.  
    9. SmsGui::~SmsGui()
    10. {
    11. 	closeMainWindow();
    12. }
    13.  
    14. void SmsGui::showMainWindow()
    15. {
    16. 	mainDialog = new QDialog;
    17. 	mainWindow = new Ui_mainWindow;
    18. 	mainWindow->setupUi(mainDialog);
    19. 	mainDialog->show();
    20. }
    21.  
    22. void SmsGui::closeMainWindow()
    23. {
    24. 	mainDialog->reject();
    25. 	delete mainDialog;
    26. 	mainDialog = NULL;
    27. 	delete mainWindow;
    28. 	mainWindow = NULL;
    29. }
    30.  
    31. void SmsGui::connectSlots()
    32. {
    33. 	connect(mainWindow->okButton, SIGNAL(clicked()), this, SLOT(clickedSend()));
    34. }
    35.  
    36.  
    37. void SmsGui::clickedSend()
    38. {
    39. 	//mainDialog->close();
    40. 	switch(mainWindow->comboBox->currentIndex())
    41. 	{
    42. 		case 0: setMiastoPlusaParameters(); return;
    43. 		case 1: /*setPlusWWWParameters();*/ return;
    44. 		default: return;	
    45. 	}
    46. }
    47.  
    48. void SmsGui::showLoginDialog()
    49. {
    50. 	QDialog *loginDialog = new QDialog;
    51. 	loginWindow = new Ui_loginDialog;
    52. 	loginWindow->setupUi(loginDialog);
    53. 	connect(loginWindow->okButton, SIGNAL(clicked()), this, SLOT(clickedLoginOk()));
    54. 	connect(loginWindow->cancelButton, SIGNAL(clicked()), this, SLOT(clickedLoginCancel()));
    55. 	loginDialog->show();
    56. }
    57.  
    58. void SmsGui::clickedLoginOk()
    59. {
    60.  
    61. 	kill();
    62. }
    63.  
    64. void SmsGui::kill()
    65. {
    66. 	loginDialog->close();
    67. }
    68.  
    69.  
    70. void SmsGui::clickedLoginCancel()
    71. {
    72. 	loginDialog->close();
    73. }
    74.  
    75. void SmsGui::setMiastoPlusaParameters()
    76. {
    77. 	showLoginDialog();
    78. }
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  2. 31st May 2006, 12:34 #2
    conexion2000
    conexion2000 is offline Novice
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    Default Re: segfault

    Problem solved. loginDialog was overriden loclly, then used uninitialized
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