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Message: [QUOTE="Eric Sosman, post: 2459917"] Kenneth Brody wrote On 04/14/06 12:58,: It does, but there are two nagging difficulties. - If `foo' has padding bits, bits that are part of its representation but not part of its value, you'll be shifting by too many places. This seems to be mostly a "theoretical" concern, as C implementations where integer types have padding bits are about as rare as snowballs in Hell. Still, the Standard permits the peculiar practice, and if such a machine is ever built Murphy's Law ensures that your code will try to run on it. - If `foo' is a signed type with a negative value, the effect of right-shifting is undefined. It may or may not be possible to shift the sign bit into a value position and then isolate it with an AND; the results simply aren't predictable. This is one of the reasons why scarred veterans (where do you think the scars came from?) recommend using unsigned types for bit-walloping. [/QUOTE]