Hello
I am using QStringlist in one of my class which return the list to other class for the future use.
Qt Code: 
  1. class test
  2. {
  3. QStringList test:: getDeviceInfoList()
  4. {
  5.  
  6.     QStringList portList;
  7.  
  8.  
  9.     if (numDevs > 0)
  10.     {
  11.         // allocate storage for list based on numDevs
  12.         devInfo = (FT_DEVICE_LIST_INFO_NODE*)malloc(sizeof(FT_DEVICE_LIST_INFO_NODE)*numDevs);
  13.  
  14.         // get the device information list
  15.         ftStatus = FT_GetDeviceInfoList(devInfo,&numDevs);
  16.  
  17.         if (ftStatus == FT_OK)
  18.         {
  19.             for (int i = 0; i < numDevs; i++)
  20.             {
  21.  
  22.                 portList.append(QString(devInfo[i].SerialNumber));
  23.             }
  24.         }
  25.          return portList;
  26.     }
  27.  
  28. }
  29. }
  30.  
  31. class test2
  32. {
  33. bool test2::connect()
  34. {
  35.     bool serialPortResponding = false;
  36.  
  37.     if (m_D2xxport->PortConfiguration( m_D2xxport->getDeviceInfoList().at(0).toStdString().c_str()));
  38.     {
  39.         serialPortResponding = true;
  40.     }
  41.     else
  42.     {
  43.         serialPortResponding = false;
  44.  
  45.     }
  46.  
  47.     return serialPortResponding;
  48.  
  49. }
  50. }
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The above code works fine if my portList contain some data.Some time it happens my portList does not contain any data in the case i get runtime error
on position
Qt Code: 
  1. if (m_D2xxport->PortConfiguration( m_D2xxport->getDeviceInfoList().at(0).toStdString().c_str()));
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I want to send null if my portList is empty or if list is empty send null if full then send portList .
QStringlist always show compile time error if i send Null or 0.