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.