Thou shalt have no other gods before the ANSI C standard 1656

You can ? The French state spends about 280 billions euros every year; in dollars, you already need 39 bits for such an amount. I would expect world trade to be much higher that that. The US federal spendings are about five times higher, as far as I know.

Moreover, bankers are really jealous about the tiny fractions of monetary units; they do not want to lose any. The european rules for trade computations between banks and big organizations mandate the use of 5 decimals, so the implementation needs 17 bits for that fractional part. We are already around 46 bits, for state spendings alone. Actual trade accounting needs more.

What I mean here is that current banking software uses 64-bit integers and seem to work, but there is not a wide margin. Conversions between different currencies require many bits to achieve an acceptable precision. And you really really do not want an overflow here (or maybe you really really wish an underflow when processing your account).

Note however that needing integers bigger than 2^64 does not mean that you need to accomodate more than 2^64 bytes of data. This is a distinct issue.

--Thomas lovein