Hi, Here is what I get when I try to link my unit tests agains boost_date_time. g++ -LC:\dev\workspace\fxoverlayFundation\Debug -LC:\dev\workspace\fxoverlayBusiness\Debug -LC:\dev\boost_1_34_1\stage\lib -ofxoverlayBusinessTests.exe emptyTests.o allTests.o InterestRateTests.o InterestCurveTests.o -lboost_date_time-mgw34-d-1_34_1 -lboost_unit_test_framework-mgw34-d-1_34_1 -lfxoverlayBusiness -lfxoverlayFundation C:\dev\workspace\fxoverlayBusiness\Debug/libfxoverlayBusiness.a(InterestCurve.o): In function `ZSt10_ConstructISt4pairIKSsN3com9fxoverlay8business12InterestRateEES6_EvPT_RKT0_': C:/dev/msys/MinGW/bin/../lib/gcc/mingw32/3.4.5/../../../../include/c++/3.4.5/bits/stl_tree.h:(.text$_ZN5boost9date_time15month_formatterINS_9gregorian10greg_monthENS0_13simple_formatIcEEcE12format_monthERKS3_RSo[boost::date_time::month_formatter<boost::gregorian::greg_month, boost::date_time::simple_format<char>, char>::format_month(boost::gregorian::greg_month const&, std::basic_ostream<char, std::char_traits<char> >&)]+0x38): undefined reference to `boost::gregorian::greg_month::as_short_string() const' C:/dev/msys/MinGW/bin/../lib/gcc/mingw32/3.4.5/../../../../include/c++/3.4.5/bits/stl_tree.h:(.text$_ZN5boost9date_time15month_formatterINS_9gregorian10greg_monthENS0_13simple_formatIcEEcE12format_monthERKS3_RSo[boost::date_time::month_formatter<boost::gregorian::greg_month, boost::date_time::simple_format<char>, char>::format_month(boost::gregorian::greg_month const&, std::basic_ostream<char, std::char_traits<char> >&)]+0x57): undefined reference to `boost::gregorian::greg_month::as_long_string() const' Both "libboost_date_time-mgw34-d-1_34_1.a" and "liboost_unit_test_framework-mgw34-d-1_34_1.a" are in "C:\dev\boost_1_34_1\stage\lib" Here are my includes : #include <boost/date_time/posix_time/ptime.hpp> #include <boost/date_time/posix_time/time_parsers.hpp> #include <boost/date_time/posix_time/time_formatters.hpp> using namespace boost::posix_time; The functions I actualy use are : from_iso_string() and to_simple_string() (wich build a ptime from a string and return a string from a ptime) I would apreciate any suggestion to make my program compile and link. Regards, Jérôme This message and any attachments (the "message") is intended solely for the addressees and is confidential. If you receive this message in error, please delete it and immediately notify the sender. Any use not in accord with its purpose, any dissemination or disclosure, either whole or partial, is prohibited except formal approval. The internet can not guarantee the integrity of this message. Overlay AM (and its subsidiaries) shall (will) not therefore be liable for the message if modified. --------------------------------------------- Ce message et toutes les pieces jointes (ci-apres le "message") sont etablis a l'intention exclusive de ses destinataires et sont confidentiels. Si vous recevez ce message par erreur, merci de le detruire et d'en avertir immediatement l'expediteur. Toute utilisation de ce message non conforme a sa destination, toute diffusion ou toute publication, totale ou partielle, est interdite, sauf autorisation expresse. L'internet ne permettant pas d'assurer l'integrite de ce message, Overlay AM (et ses filiales) decline(nt) toute responsabilite au titre de ce message, dans l'hypothese ou il aurait ete modifie.