SIGSEGV (Segmentation fault) - Bad Pointer i guess

Matthacker

Hi I have made a code for a system, an when I try to run it it crashes and comes with the code
Signal name: SIGSEGV
Signal meaning: Segmentation fault

I think that it is because I am using a pointer incorrect, but cant figure out why it is wrong

I have made a pointer in a class and want to use it in my mainwindow, and I have made a pointer in my mainwindow which i want to use in my class aswell. I know thats abit tricky.

here is my code.
@
#ifndef SERIALSETUP_H
#define SERIALSETUP_H
#include <QMessageBox>
#include <QDebug>
#include <QSerialPort>

#include "mainwindow.h"

class SerialSetup
{
public:
SerialSetup(MainWindow *myWindowPtr);
void setupSerial();

private:
MainWindow *myWindowPtr_;
QSerialPort *serialPtr_;
};

#endif // SERIALSETUP_H

@

#include "serialsetup.h"

SerialSetup::SerialSetup(MainWindow *myWindowPtr)
{
myWindowPtr_ = myWindowPtr;
}

void SerialSetup::setupSerial()
{
serialPtr_ = new QSerialPort(myWindowPtr_); // this is where it goes wrong!
serialPtr_ ->setPortName("COM2");

if(serialPtr_->open(QIODevice::ReadWrite))
{
    qDebug("Serial Opened");
    QMessageBox::information(myWindowPtr_,myWindowPtr_->tr("Succesfull"),myWindowPtr_->tr("Succesfully connected to STK"));
    serialPtr_->setBaudRate(QSerialPort::Baud9600);
    serialPtr_->setDataBits(QSerialPort::Data8);
    serialPtr_->setParity(QSerialPort::NoParity);
    serialPtr_->setStopBits(QSerialPort::OneStop);
    serialPtr_->setFlowControl(QSerialPort::NoFlowControl);
    myWindowPtr_->connect(serialPtr_,SIGNAL(readyRead()),myWindowPtr_,SLOT(serialReceived()));
}
else
{
    QMessageBox::warning(myWindowPtr_,myWindowPtr_->tr("Error"),myWindowPtr_->tr("Connection failed"));
    qDebug ("Serial NOT Opened");
    qDebug() << "error code = " << serialPtr_->error();
    qDebug() << "error string = " << serialPtr_->errorString();
}

}
@

and my mainwindow

@
#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include <QSerialPort>
#include <QTimer>
#include "modify_scenario.h"

class SerialSetup;

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
Q_OBJECT

public:
explicit MainWindow(QWidget *parent = 0, SerialSetup *setupPtr = 0 );

~MainWindow();

private slots:
void serialReceived();
void on_Modify_button_clicked();
void on_On_button_clicked();
void on_Off_button_clicked();
void on_Minus_button_clicked();
void on_Plus_button_clicked();
void on_Scenario1_button_clicked();
void on_Scenario2_button_clicked();
void on_Scenario3_button_clicked();
void on_Load_button_clicked();
void fcheckButton1();
void fcheckButton2();
void fcheckButton3();
void fcheckLocked();
//void serialSetup();
void timeSetup();
private:
Ui::MainWindow *ui;
Modify_Scenario *modify;
SerialSetup *setupPtr_;
QSerialPort *serial1Ptr_;
QTime *time;
bool Scenario1Chk, Scenario2Chk, Scenario3Chk, LockedChk,OpenChk;
int counter;

};

#endif // MAINWINDOW_H

@

@
#include "ui_mainwindow.h"
#include "modify_scenario.h"
#include "serialsetup.h"

MainWindow::MainWindow(QWidget *parent, SerialSetup *setupPtr) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{

 ui->setupUi(this);

 setupPtr_ = setupPtr;
 setupPtr_ ->setupSerial();

@

can any of you figure out whats wrong ?

Alex.

andreyc

Where do you allocate SerialSetup?
Is myWindowPtr_ a valid pointer at this line?
@
serialPtr_ = new QSerialPort(myWindowPtr_);
@

There is no any threads except main GUI thread in your app, right?

andreyc

I think the fact that you are using myWindowPtr_ inside MainWindow constructor makes myWindowPtr_ invalid.

Matthacker

Hi Andreyc

thanks for your response.

Have made the class SerialSetup to make the MainWindow cpp smaller.

before I had
@serialPtr_ = new QSerialPort(this); @

inside MainWindow, and that worked. now instead of using this pointer I needed to have a pointer to the mainwindow and put it in there. but cant understand why that is wrong.

dont think I am using the myWindowPtr_ inside MainWindow constructor, though I use it in SerialSetup constructor.

Alex.

andreyc

Could you show where do you create SerialSetup object?

Matthacker

ahh I forgot to initialize the constructor, it never got in to it.!
figured it out ;)

thanks.!

andreyc

Glad you solved it.
Could you put [SOLVED] in the title of you message. Thanks.