Very Computer

> But it is actually in the header file and the program is able to use it.
> Could it be, that this problem occurs because I am running Linux?
> Thanks for your help
> Benjamin

> + Hi,
> + well I thought someone might have read this book

> Oh man, who /hasn't/ read that book?  The APUE is great.  (May Stevens
> rest in peace.)

> + and can help me with
> + the following programming problem:
> + When I use the error function that is defined in the ourhdr.h file I get
> + an error message:
> + In function main:
> + undefined reference to 'err_quit'
> +
> + But it is actually in the header file and the program is able to use it.
> + Could it be, that this problem occurs because I am running Linux?

> Linux is a Unix.  Linux has naught to do with it.

> The problem (methinks) is that the ourhdr.h file /declares/ err_quit but
> does not /define/ it.  There is a difference.  Take a look at err_quit in
> the header file; if it starts off with "extern" then it's probably just
> a declaration, not a definition.  (This is a fairly common mistake for
> beginning programmers.  You should read the comp.unix.programming FAQ.)

> You need to find where err_quit is actually defined, and make certain
> you're linking that in as well.

> I'd say more, but 1) I don't have the APUE with me and I'm just going on what
> you've written here, and 2) discovering it yourself will teach you more.  :-)

> Luck++;
> Phil

> > Luck++;
> > Phil

> Sure you are right discovering it myself would teach me more. But for
> that I have to discover it at all!
> I also tried the sources that Richard Stevens published on his
> Webserver. And when I use exclusivly his files it still doesn't work. So
> I don't erally know where to search for a solution.
> Benjamin

> > well I thought someone might have read this book

> Quite a few of us, I suppose. Welcome to the club. ;-)

> > In function main:
> > undefined reference to 'err_quit'

> > But it is actually in the header file and the program is able to use
> > it.

> Including a header does not mean your program can use the function.
> It only means your program will compile. It won't link though - for
> that you need to link the actual definition (as opposed to
> declaration) of the function. Get the code for err_quit() [IIRC, it is
> available on the net], or type it in yourself, and link it in.  Check
> your compiler/linker documentation to see how to do it. On Linux with
> gcc the easiest way is, assuming the function definition is in
> ourerr.c, and your program is in prog.c, and all that + ourhdr.h is in
> the current directory:

> $ gcc prog.c ourerr.c

> > Could it be, that this problem occurs because I am running Linux?

> Nothing to do with Linux. It's not an OS question at all, it's C.

> --

> "... We work but wit, and not by witchcraft;
>  And wit depends on dilatory time." [Shakespeare]