multifile project

From: Anders Christensen (andersc1_at_hotmail.com)
Date: 05/20/05 

Date: Fri, 20 May 2005 13:47:57 +0200

I'm writing a program with multiple files. I need some good advices on
how to handle the include's. Brief explaination of the situation:

I have a "main.c" and some header-/source files *.c and *.h .
In the top of "main.c" I include the headerfiles "first.h", "second.h" and
"last.h". From "main.c" I'm now able to access the functions and variables
that are declared/defined in the header/soucefiles.

The problem is that I'd like the functions/variables from "first.c" to be
accessable from within "second.c" and "last.c". Therefore, in the top of
"second.c" and "last.c" respectively, I include the headers "second.h" and
"last.h".

Moreover, I'd like functions and variables from "first.c" and "second.c"
to be known in "last.c", so in the top of "last.c" i include the two
headerfiles "first.h" and "second.h".

I compile the program with the command
   gcc main.c first.c second.c last.c -o prog

This actually worked out fine for a long time, but now I get some
strange errors as I try to expand the project with more
source-/headerfiles.

All my headers are protected by #ifndef

Is it the wrong way I do the includes? Any suggesions?

./Anders.