Hi, LINUX and HP/UX have different strerror_r functions. At least for me the moduification works. regards, Oliver std::string errno_md( const error_code & ec ) { # if !defined(BOOST_WINDOWS_API) // does not have strerror_t #if defined(__linux) char buf[64]; char * bp = buf; std::size_t sz = sizeof(buf); return strerror_r( ec.value(), bp, sz); #elif defined(__hpux) return strerror( ec.value() ); #else char buf[64]; char * bp = buf; std::size_t sz = sizeof(buf); int result; while ( (result = strerror_r( ec.value(), bp, sz )) == ERANGE ) { if ( sz > sizeof(buf) ) std::free( bp ); sz *= 2; if ( (bp = static_cast<char*>(std::malloc( sz ))) == 0 ) return std::string( "ENOMEM" ); } std::string msg( ( result == EINVAL ) ? "EINVAL" : bp ); if ( sz > sizeof(buf) ) std::free( bp ); return msg; # endif # else const char * c_str = std::strerror( ec.value() ); return std::string( c_str ? c_str : "EINVAL" ); # endif }