Does not say anything about the size.
3.9.1.8
There are three floating point types: float, double, and long double.
The type double provides at least as much precision as float, and the
type long double provides at least as much precision as double. The
set of values of the type float is a subset of the set of values of
the type double; the set of values of the type double is a subset of
the set of values of the type long double. The value representation of
floating-point types is implementation-defined. Integral and floating
types are collectively called arithmetic types. Specializations of the
standard template std::numeric_limits (18.3) shall specify the maximum
and minimum values of each arithmetic type for an implementation.
