| -----Original Message----- | From: boost-bounces@lists.boost.org | [mailto:boost-bounces@lists.boost.org] On Behalf Of Alexander Nasonov | Sent: 12 July 2006 16:27 | To: boost@lists.boost.org | Subject: Re: [boost] [lexical_cast] performace patch | | Alexander Nasonov wrote: | >I googled for lexical_cast on www.open-std.org recently but | found no proposal. Now I see it: | >http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2006/n1973.html | | BTW, | | 1. unsetf(std::ios::skipws) is not mentioned in the doc | 2. loopback tests may fail | | N1973: "If std::numeric_limits<Target>::is_specialized, the | underlying stream precision is set according to | std::numeric_limits<Target>::digits10 + 1, otherwise if | std::numeric_limits<Source>::is_specialized, the underlying | stream precision is set according to | std::numeric_limits<Source>::digits10 + 1." | | See http://article.gmane.org/gmane.comp.lib.boost.devel/145097 As I said before - it is the wrong formula :-(( It gives the wrong number of digits for float and will probably also fail for user defined types. Since it is for TR2, it should be specified in terms of max_digits10, now accepted for TR2. I suggest you use the right formula from digits not digits10 for now. If you've serialized a lot of stuff, you might be cross not to get back as near as possible what you've saved. And you'd probably waste a lot of time trying to find out why not. (This is a separate issue from the double loopback failures - even in MSVC, float loopback IS correct for ALL float values - there are few enough of them for an exhaustive test ;-) Paul --- Paul A Bristow Prizet Farmhouse, Kendal, Cumbria UK LA8 8AB +44 1539561830 & SMS, Mobile +44 7714 330204 & SMS pbristow@hetp.u-net.com