UDPSocket Stopped Working

M4RZB4Ni

Hello
I Want To Save state of a combobox in Char variable and send The Amount of this variable
by UdpSocket to Client and when Client Received Amount of variable Disable or Enable Some Objects
I Wrote a Code For Doing This But When i Run This Code Show me Stopped Working Messsage!
SomeBody Can Help me Please?
.h file

    QUdpSocket *uSocket;

.cpp file

QSettings priSettings("Mobtakeran Fanavri KabooK","Kabook Physiothrapy");
management_menu::management_menu(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::management_menu)
{
 ui->setupUi(this);
primessionOfNewUser();

}

void management_menu::primessionOfNewUser()
{
    char priChkNuser;
    QByteArray *priPackNuser;
    if(ui->chkNewUser->currentIndex()==0)
    {
       priChkNuser='y';
       priPackNuser->append(priChkNuser);
       uSocket->writeDatagram(priPackNuser->data(),priPackNuser->size(),QHostAddress::Broadcast,45454);
       priSettings.setValue("PNU",ui->chkNewUser->currentIndex());
    }else if(ui->chkNewUser->currentIndex()==1){
        priChkNuser='n';
        priPackNuser->append(priChkNuser);
        uSocket->writeDatagram(priPackNuser->data(),priPackNuser->size(),QHostAddress::Broadcast,45454);
        priSettings.setValue("PNU",ui->chkNewUser->currentIndex());

    }

}

mrjj

hi
do you have

uSocket = new QUdpSocket(this) ;

anywhere?

M4RZB4Ni

@mrjj
hi
no! i dont this
why??

SGaist

Hi,

You're not allocating priPackNuser so you're using an invalid pointer.

In any case, there's no need to allocate priPackNuser on the heap. You should keep it on the stack.

M4RZB4Ni

hi
thank you so much
can you
explain more and
Correction my code please?

i have abut 10 more function like this and if you correction this I would be grateful.

mrjj

@M4RZB4Ni said:

Hi
When you dont have
uSocket = new QUdpSocket(this) ;
then
uSocket->writeDatagram(xx
will crash.
as uSocket just point to random location. (dangling pointer)

Next:
QByteArray *priPackNuser; <<< also just a pointer.
You should do ( as @SGaist mention)
QByteArray priPackNuser;
( no *, means its real bytearray, not a pointer to one)
So you change it from heap allocation to stack allocation.

If you dont change to non pointer then you need
QByteArray *priPackNuser = new QByteArray ;
as else its a dangling pointer too!
But no need for pointer to QByteArray here.