On 25/09/06, John Maddock <john@johnmaddock.co.uk> wrote:
There are a couple of problems: and you are correct on both counts, there are no long double versions of the math functions (there are no *l versions, the std::func versions do have long double overloads but they call the double versions internally). And numeric_limits<long double> is wrong as well, see http://tinyurl.com/mof7j
In fact numeric_limits<long double> has some really strange properties: it's min/max values correspond to an 80-bit long double with an extended exponent range, but the digits and epsilon values are those of a 64-bit double. Oh but LDBL_EPSILON and LDBL_MANT_DIG are correct!
That's on FreeBSD, my problem was with OpenBSD (http://tinyurl.com/o6rty) but it seems that both are wrong. OpenBSD is the other way round, the macros say that long double is 64-bit but numeric_limits claims 80-bit. So it ends up with numeric_limits::min()==0, max()==inf. Hopefully all I have to do is use the macros for the BSDs.
BTW the math_info program results were designed to diagnose precisely these kinds of issues,
HTH,
Very helpful, thank you. I'll look at it closer tonight. Daniel