On running memcheck for the following code:

Qt Code: 
  1. #include <QApplication>
  2. #include <QPushButton>
  3.  
  4. int main(int argc, char *argv[])
  5. {
  6.     QApplication app(argc, argv);
  7.     QWidget window;
  8.  
  9.     window.resize(600, 600);
  10.     QPushButton button(&window);
  11.     window.show();
  12.  
  13.     return app.exec();
  14. }
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These errors are obtained on checking the external error flag for memcheck:

Qt Code: 
  1. Syscall param writev(vector[...]) points to uninitialised byte(s)
  2. Address 0xcc7be09 is 4,537 bytes inside a block of size 21,152 alloc'd  1: calloc in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so
  3. Uninitialised value was created by a stack allocation  1: non-virtual thunk to QXcbWindow::setVisible(bool) in /home/captaindavinci/Qt/5.8/gcc_64/lib/libQt5XcbQpa.so.5.8.0
  4.  
  5. Location is main.cpp: 7
  6. and so on..
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