V664. Pointer is dereferenced on the initialization list before its check for null inside the body of a constructor function.

The pointer is being dereferenced in the constructor initialization list and then checked inside the constructor body for not being a null pointer. It may signal a hidden error that may stay unnoticed for a long time.

Consider a sample of incorrect code:

Layer(const Canvas *canvas) :
  about(canvas->name, canvas->coord)
{
  if (canvas)
  {
    ....
  }
}

When dereferencing a null pointer, undefined behavior occurs, i.e. normal execution of the program becomes impossible. To fix the error you should move the initialization operation into the constructor body in the code block where the pointer is known to not be equal to zero. Here is the fixed code:

Layer(const Canvas *canvas)
{
  if (canvas)
  {
    about.set(canvas->name, canvas->coord);
  }
}

This diagnostic is classified as: