hi this is given me some error I cannot locate a fix. thanks **************** code **************** #include <iostream> #include <string> #include "boost/filesystem/operations.hpp" // includes boost/filesystem/path.hpp #include "boost/filesystem/fstream.hpp" namespace fs = boost::filesystem; using namespace std; int main(){ fs::path full_path("../data"); if (exists(full_path)) cout << "yes" << endl; } //there exists data directory in the parent of the current directory. **************** error **************** $ make g++ -gdwarf-2 -c -o try.o try.cpp g++ -Wall -gdwarf-2 -o proj try.o try.o: In function `main': /home/fred/myPrograms/backtest/try/try.cpp:11: undefined reference to `boost::filesystem::path::path(char const*)' /home/fred/myPrograms/backtest/try/try.cpp:12: undefined reference to `boost::filesystem::exists(boost::filesystem::path const&)' collect2: ld returned 1 exit status make: *** [proj] Error 1 __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com