64 bit architectures and C/C++

[shap]

Several companies have announced or are known to be working on 64 bit
architectures. It seems to me that 64 bit architectures are going to
introduce some nontrivial problems with C and C++ code.

I want to start a discussion going on this topic.  Here are some seed
questions:

1. Do the C/C++ standards need to be extended to cover 64-bit
environments, or are they adequate as-is?

2. If a trade-off has to be made between compliance and ease of
porting, what's the better way to go?

3. If conformance to the standard is important, then the obvious
choices are

	short	16 bits
	int	32 bits
	long	64 bits
	void *	64 bits

How bad is it for sizeof(int) != sizeof(long). 

4. Would it be better not to have a 32-bit data type and to make int
be 64 bits?  If so, how would 32- and 64- bit programs interact?

Looking forward to a lively exchagne...