Changed subject to see if it gets any attention... <dariomt <at> gmail.com> writes:
Hi, Quoting the docs for boost::numeric_cast: "There are several situations
where conversions are unsafe: [...] Conversions from floating point types to integral types."
What about conversions from integral types to floating point types? E.g.
from 64bit int to double.
The following example shows what I mean:
#include <iostream> #include <cmath> #include <boost/numeric/conversion/cast.hpp>
int main() { const uint64_t i = 123445678911188878; std::cout << "i=" << i << std::endl; const double d = i; std::cout << "d=" << std::fixed << d << std::endl; std::cout << "next=" << std::fixed << std::nextafter(d,
std::numeric_limits<double>::max() ) << std::endl;
std::cout << "prev=" << std::fixed << std::nextafter(d, - std::numeric_limits<double>::max()) << std::endl; // I'd expect the following cast to fail const double dd = boost::numeric_cast<double>(i); std::cout <<"dd=" << std::fixed << dd << std::endl;
return 0; }
prints
i=123445678911188878d=123445678911188880.000000next=123445678911188896.00000 0prev=123445678911188864.000000dd=123445678911188880.000000because that integer cannot be represented in double precisionIs there something in Boost to help here?Thanks in advance