>> Mhmm, I don't see how that works. How do I get the max value from a
>> low_bit_mask_t? It should be 2^n-1 with n being the number the bits.
>
>
> low_bits_mask_t<n>::sig_bits
>
> Not?

Yes. Thanks! It works but not for n = 64. It gives a wrong value:

typedef boost::low_bits_mask_t<64> mask_t;
mask_t::least oo = mask_t::sig_bits;

Does that work for you?

Yes, I got 18446744073709551615

http://liveworkspace.org/code/3xi9dD$0