Hello, here is a small piece of code that use the posix_time system that fails to compile. I'm wondering whether it is a bug in the library or my usage of the library that is wrong. Thank you for your help. Istvan #include "boost/date_time/posix_time/posix_time.hpp" #include <iostream> int main() { using namespace boost::posix_time ; ptime now = microsec_clock::local_time(); std::cout << to_simple_string( now ) << std::endl ; return 0 ; } g++ -I/opt/boost brol.cpp /tmp/ccQQjwdW.o(.gnu.linkonce.t._ZN5boost9date_time15month_formatterINS_9gregorian10greg_monthENS0_13simple_formatEE12format_monthERKS3_RSo+0x3a): In function `boost::date_time::month_formatter<boost::gregorian::greg_month, boost::date_time::simple_format>::format_month(boost::gregorian::greg_month const&, std::basic_ostream<char, std::char_traits<char> >&)': : undefined reference to `boost::gregorian::greg_month::as_short_string() const' /tmp/ccQQjwdW.o(.gnu.linkonce.t._ZN5boost9date_time15month_formatterINS_9gregorian10greg_monthENS0_13simple_formatEE12format_monthERKS3_RSo+0x5c): In function `boost::date_time::month_formatter<boost::gregorian::greg_month, boost::date_time::simple_format>::format_month(boost::gregorian::greg_month const&, std::basic_ostream<char, std::char_traits<char> >&)': : undefined reference to `boost::gregorian::greg_month::as_long_string() const' collect2: ld returned 1 exit status The system is running SuSE linux 9.0 compiler: gcc 3.3.1 boost version 1.30.2