Structs
The error handling form of the special functions always calculate an error estimate along with the value of the result.
Therefore, structures are provided for amalgamating a value and error estimate.
In some cases, an overflow or underflow can be detected and handled by a function.
In this case, it may be possible to return a scaling exponent as well as an error/value pair in order to save the result from exceeding the dynamic range of the built-in types.