[SOLVED] Understanding Segmentation fault in Qt project through GDB

Aquarius_Girl · 02-02-2011, 02:21 AM

I ve added the following to the .pro file, if that matters:

Code:

QMAKE_CXXFLAGS_DEBUG *= -pg
QMAKE_LFLAGS_DEBUG *= -pg

I need to understand where to look when I get the following through GDB:
The print statement shown in Green gets printed and then I receive the SEG fault, I don't know where the control goes then? Any hints?

Code:

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x7ffff2338910 (LWP 17107)]
QHostAddressPrivate::clear (this=0x0) at /var/tmp/qt-src/src/network/kernel/qhostaddress.cpp:292
292     /var/tmp/qt-src/src/network/kernel/qhostaddress.cpp: No such file or directory.
        in /var/tmp/qt-src/src/network/kernel/qhostaddress.cpp

Relevant code:
This is a client server program. When the client gets closed, this gets called:

Code:

connect (objTcpSocketUtility->objTcpSocket, SIGNAL (error(QAbstractSocket::SocketError)), this, SLOT (socketError (QAbstractSocket::SocketError)), Qt::DirectConnection);

socketError calls closeConnection

Code:

closeConnection()
{
   objTcpSocketUtility->destroy_Socket ();
   printf ("\n==========I think=====================\n");
}

and the destroy_Socket contains this:

Code:

void destroy_Socket()
{
   objTcpSocket->close ();
   delete objTcpSocket;

   objTcpSocket = NULL; 
}

Aquarius_Girl · 02-02-2011, 05:36 AM

SOLVED:

Now I realize I didn't mention that I had stored that socket pointer in a vector (shallow copy) so when the destroy_socket function deleteed the socket, the shallow copy in the vector became a dangling pointer and thus resulted in a SEG fault!