There is a Filesystem bug report, 5048, that actually affects any library using ...\libs\detail\utf8_codecvt_facet.cpp The problem is line 255: #elif WCHAR_MAX > 0x10000 On HP-UX, WCHAR_MAX is defined like this: # if defined(_INCLUDE_STDCSOURCE_199901) # define WCHAR_MAX UINT_MAX /* max value of an unsigned integer */ # define WCHAR_MIN 0 # else # define WCHAR_MAX (wchar_t)UINT_MAX /* max value of an unsigned integer */ # define WCHAR_MIN (wchar_t)0 # endif An obvious fix is to add #define _INCLUDE_STDCSOURCE_199901 to ...\boost\config\platform\hpux.hpp, and that's been confirmed by the user who originated the bug report. I'm guessing that this fix doesn't work if the user includes <stdint.h> before <boost/config.hpp>, but can't think of anything better. Any objections to committing the change to ...\boost\config\platform\hpux.hpp? --Beman