The header file that you need to use the interface are in the
    include/yaz directory. It's called
    backend.h. It will include other files from
    the include/yaz directory, so you'll
    probably want to use the -I option of your compiler to tell it
    where to find the files. When you run
    make in the top-level YAZ directory,
    everything you need to create your server is to link with the
    lib/libyaz.la library.