There are two components to the library: a header file ``fh.h'' and the implementation, ``fh.c''.
Programs which libfh as part of Pegasus can include the header file like this:
Linking with the library is accomplished by adding -lfh to the $(EXECNAME) line of the Makefile:
$(EXECNAME): $(OBJS) -lfh
The above applies to projects in the CFHT source tree, /cfht/src/...
If you made your own copies if fh.h and fh.c, include just ``fh.h'' instead of ``fh/fh.h'' and link fh.c into your program as just another C file.