As of patch 113817-04 to the Sun C++ 5.5 compiler (see http://sunsolve6.sun.com/search/document.do?assetkey=1-21-113817 ), the functions in the numeric_limits class support 64 bit integers. However, the logic in boost/boost/config/stdlib/roguewave.hpp doesn't detect this a defines BOOST_NO_LONG_LONG_NUMERIC_LIMITS and hence causes an error: "../../../../boost/boost/limits.hpp", line 35: Error: Multiple declaration for std::numeric_limits<long long>. "../../../../boost/boost/limits.hpp", line 88: Error: Multiple declaration for std::numeric_limits<unsigned long long>. 2 Error(s) detected. As __SUNPRO_CC is set to 0x550 for both compilers below and above patchlevel 04, I can't see a way to fix this without extending the logic in the CVS head, for handling Sun C++ 5.6, to 5.5 and breaking unpatched installations. -- Wishing you good fortune, --Robin Kay-- (komadori)