Synopsis

namespace boost{ namespace math
{
  // Values for flags.
  const int legacy;
  const int signed_zero;
  const int trap_infinity;
  const int trap_nan;

  template<
      class CharType,
      class OutputIterator = std::ostreambuf_iterator<CharType>
  >
  class nonfinite_num_put : public std::num_put<CharType, OutputIterator>
  {
  public:
      explicit nonfinite_num_put(int flags = 0);
  };

  template<
      class CharType,
      class InputIterator = std::istreambuf_iterator<CharType>
  >
  class nonfinite_num_get : public std::num_get<CharType, InputIterator>
  {
  public:
      explicit nonfinite_num_get(int flags = 0);  // legacy, sign_zero ...
  };
}} // namespace boost namespace math

To use these facets

#include <boost\math\special_functions\nonfinite_num_facets.hpp>