I attach links to a proposal for very tiny addition to the numeric_limits. It provides an easy way for the novice to ensure that all potentially significant digits are output. For example, for float 6 decimal digits are guaranteed, but 9 may be significant. This is used in Boost test, and should be useful for lexical_cast, serialization etc. Comments, objections, better name suggestions, etc welcome. Paul http://www.hetp.u-net.com/public/Cpp/numeric_limits%20significant%20digits.p df aka http://tinyurl.com/9qxdk Paul A Bristow Prizet Farmhouse, Kendal, Cumbria UK LA8 8AB +44 1539 561830 +44 7714 330204 mailto: pbristow@hetp.u-net.com