The documentation for the date_time library states that a ptime can be
constructed from a special value
e.g.
   ptime(special_values sv)
   ptime t1(neg_infin);
   ptime t2(pos_infin);
   ptime t3(not_a_date_time);

However when I try this with the Cygwin GNU compiler I get a  no matching
function for call error (see errors below)
Am I missing something here or is the documentation wrong?

Thanks
Matt

../../logview.cpp:1843: error: no matching function for call to `
  boost::posix_time::ptime::ptime(boost::date_time::special_values)'
c:/cygwin/usr/local/include/boost-1_31/boost/date_time/posix_time/ptime.hpp:
32: error: candidates
  are: boost::posix_time::ptime::ptime(const boost::posix_time::ptime&)
c:/cygwin/usr/local/include/boost-1_31/boost/date_time/posix_time/ptime.hpp:
45: error:
                 boost::posix_time::ptime::ptime(const
  boost::posix_time::int64_time_rep&)
c:/cygwin/usr/local/include/boost-1_31/boost/date_time/posix_time/ptime.hpp:
42: error:
                 boost::posix_time::ptime::ptime(boost::gregorian::date)
c:/cygwin/usr/local/include/boost-1_31/boost/date_time/posix_time/ptime.hpp:
39: error:
                 boost::posix_time::ptime::ptime(boost::gregorian::date,
  boost::posix_time::time_duration)