TITLE: New cast notation for C++ - reinterpret_cast

[ Material taken from "C++ Report", Sept. 94, Vol. 6, No. 7,
  pp 46-51. ]

(continued info on new casts)

This article discusses the new reinterpret_cast mechanism, whose
syntax is roughly

	reinterpret_cast<T> (expr)

It was design to be used for conversions which are inherently 
unsafe. It returns a value that is a low-level bit representation
of the expression.

This is used for converting

	completely unrelated pointer types
	unrelated function pointer types
	integer to pointer types

Note that this cast should not be used for casting pointers
to navigate a class heirarchy:

	class X {};
	class Y {};
	class Z : public X, public Y {};

	void foo (Y* py)
	{
		Z* pz1 = static_cast<Z*> (py);      // ok
		Z* pz2 = reinterpret_cast<Z*> (py); // oops!
	}

	extern Z z;
	f (z);

Using the compile-time static type information, static_cast will
convert Y* to Z*, causing pz1 to point to the start of the object
of type Z to which py is assumed to point. The pz2 will be directly
initialized with the unchanged value of py (still INCORRECTLY 
pointing to the object of type Y).