Ticket #9177: basic_text_oprimitive.hpp.2.patch

basic_text_oprimitive.hpp

@@ -136 +136 @@
     // we'll get a compile time error. This is meant to automatically
     // support synthesized types which support floating point
     // operations. Also it should handle compiler dependent types
-    // such long double.  Due to John Maddoc.
+    // such long double.  Due to John Maddock.
 
     template<class T>
     struct is_float {
@@ -156 +156 @@
             boost::serialization::throw_exception(
                 archive_exception(archive_exception::output_stream_error)
             );
+#ifndef BOOST_NO_CXX11_NUMERIC_LIMITS
+        const unsigned int digits = std::numeric_limits<T>::max_digits10;
+#else
         // The formulae for the number of decimla digits required is given in
         // http://www2.open-std.org/JTC1/SC22/WG21/docs/papers/2005/n1822.pdf
         // which is derived from Kahan's paper:
         // http://http.cs.berkley.edu/~wkahan/ieee754status/ieee754.ps
-        const unsigned int digits = (std::numeric_limits<float>::digits * 3010) / 10000;
-        os << std::setprecision(digits);
+        const unsigned int digits = std::numeric_limits<T>::radix == 2 ? (std::numeric_limits<T>::digits * 3010) / 10000 : std::numeric_limits<T>::digits10;
+#endif
+        os << std::setprecision(digits) << std::scientific;
         os << t;
     }