I was trying to use QFileDialog::getOpenFileName static function,when i ran my app normally not in debugging mode it runs fine, but when i ran it in my debugger (GDB) i encountered some "segmentation fault"

please see my code below
Qt Code: 
  1. void MyFunc::openCFGFile(void)
  2. {
  3.     QString strFile = QFileDialog::getOpenFileName(this,
  4.                       tr("Select Configuration File To Open"),"",
  5.                       "Configuration File (*.cfg)"); // <--segmentation fault happen here
  6.     if (strFile.isEmpty())
  7.         return;
  8.     //store cfgFile
  9.     cfgFile = new QFile(strFile);
  10.     if (!cfgFile->open(QFile::ReadOnly))
  11.     {
  12.         QMessageBox::warning(this, tr("File Open Error"),
  13.                              tr("Cannot Open file %1:\n%2.")
  14.                              .arg(strFile)
  15.                              .arg(cfgFile->errorString()));
  16.         cfgFile->close();
  17.         return;
  18.     }
  19.     cfgFile->close();
  20. }
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please tell me what did i do wrong?

baray98