Jan Robbe wrote: > Maybe you can have a look at the makefile i use, i dont really know > how to tell the file to link to the library.. That looks like the libPlt makefile - you need to link in X11 from the xfoil makefile. (Oddly there's a ranlib line in the libPlt makefile that has -lX11 - maybe that was intended to somehow merge the right bits into libPlt? I didn't think ranlib could do that.) You need to find the line that links xfoil in the other makefile and add -lX11 to the end of it. It might look something like this: all: xfoil xfoil: $(OBJS) $(FC) -o $@ $(OBJS) $(PLTLIB) but there are many ways to write a makefile - it might look entirely different! Rup. ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email ______________________________________________________________________