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diff --git a/boost/math/special_functions/ulp.hpp b/boost/math/special_functions/ulp.hpp
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+//  (C) Copyright John Maddock 2015.
+//  Use, modification and distribution are subject to the
+//  Boost Software License, Version 1.0. (See accompanying file
+//  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef BOOST_MATH_SPECIAL_ULP_HPP
+#define BOOST_MATH_SPECIAL_ULP_HPP
+
+#ifdef _MSC_VER
+#pragma once
+#endif
+
+#include <boost/math/special_functions/math_fwd.hpp>
+#include <boost/math/policies/error_handling.hpp>
+#include <boost/math/special_functions/fpclassify.hpp>
+#include <boost/math/special_functions/next.hpp>
+
+namespace boost{ namespace math{ namespace detail{
+
+template <class T, class Policy>
+T ulp_imp(const T& val, const Policy& pol)
+{
+   BOOST_MATH_STD_USING
+   int expon;
+   static const char* function = "ulp<%1%>(%1%)";
+
+   int fpclass = (boost::math::fpclassify)(val);
+
+   if(fpclass == (int)FP_NAN)
+   {
+      return policies::raise_domain_error<T>(
+         function,
+         "Argument must be finite, but got %1%", val, pol);
+   }
+   else if((fpclass == (int)FP_INFINITE) || (fabs(val) >= tools::max_value<T>()))
+   {
+      return (val < 0 ? -1 : 1) * policies::raise_overflow_error<T>(function, 0, pol);
+   }
+   else if(fpclass == FP_ZERO)
+      return detail::get_smallest_value<T>();
+   //
+   // This code is almost the same as that for float_next, except for negative integers,
+   // where we preserve the relation ulp(x) == ulp(-x) as does Java:
+   //
+   frexp(fabs(val), &expon);
+   T diff = ldexp(T(1), expon - tools::digits<T>());
+   if(diff == 0)
+      diff = detail::get_smallest_value<T>();
+   return diff;
+}
+
+}
+
+template <class T, class Policy>
+inline typename tools::promote_args<T>::type ulp(const T& val, const Policy& pol)
+{
+   typedef typename tools::promote_args<T>::type result_type;
+   return detail::ulp_imp(static_cast<result_type>(val), pol);
+}
+
+template <class T>
+inline typename tools::promote_args<T>::type ulp(const T& val)
+{
+   return ulp(val, policies::policy<>());
+}
+
+
+}} // namespaces
+
+#endif // BOOST_MATH_SPECIAL_ULP_HPP
+