You can save the libraries anywhere sensible.  I would strongly suggest that the actual library file be named libfltk.a or something similar.  The lib prefix is important because the compiler prefers this format.

When you're attempting to access them in another project, you'll need to add two things to your project options.  First, open the Project Options dialog and select the File Locations tab.  You'll see a button labeled "Search Directories."  Click this button to open the Directories dialog.  Next, select the Library Directories tab and click the "Add" button.  Navigate in the selection dialog to the directory where your FLTK library of the appropriate architecture lies.  Select "Ok" to close the selection dialog, then select "Ok" to close the Directories dialog.

To actually add a reference to your library, you'll next need to select the Compiler Flags tab in the Project Options dialog.  In this tab, you'll need to enter your library in the Linker box.  In this example, enter:

-lfltk

The format will be a dash followed by a lowercase "L" followed by the name of the library minus the lib prefix and without any extension.  Select Ok to close the Project Options dialog.  Now save your project and perform a Clean and Build.

Let me know if the above makes sense.  I'll be happy to provide additional assistance.

I am trying to write the fortran interface for this c++ library

Thanks

Dave

   OPTIONS >
                  > Project Options >
                                               > Compiler flags >
                                                                          > Package flags

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??

Jw