Re: [boost] [functional] boost::hash with 64-bit types

Daniel James wrote:

Peter Dimov wrote:

...

For larger integer types, we probably need something along the lines of

std::size_t hash_value( val ) { size_t r = val;

while( val >>= size_t_bits ) { hash_combine( r, (size_t)val ); }

return r; }

It has the property of preserving the hash_value of all _values_ that can fit into a size_t, even though the underlying type is capable of holding bigger integers.

I don't think it does.

Actually, it does for positive number. Sorry I misread it. What you were doing clicked a couple of seconds after I clicked on 'send'. But I'm not sure it works for negative numbers. Daniel