Hi I am a newbie on using gcc and linking files. I have defined some classes (.h and .cpp files) which I want to use in my main function defined in a source file(containing the main() function. I have kept all the class files (.h and .cpp) along with the .cpp source file in one directory. When I compile only using : g++ source.cpp it compiles fine. However, when I try to link it too, by writing: g++ source.cpp -o source_e I get a series of errors containing : undefined reference to func (say) where func is say, a function I have declared in one of my class files. It seems that it is not able to link properly . I have included the header files of the classes in the source file. However I am still getting this error. I tried specifying the directory where all these files are by the -B option but it did not help either. Please help me out! Thanks a lot. Regards Koyel