From: Richard Lanyon <rlanyon AT plato DOT wadham DOT ox DOT ac DOT uk>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: Undefined reference to `main'
Date: Sun, 19 Jul 1998 17:42:50 +0100
Organization: Oxford University
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On Sun, 19 Jul 1998, Eli Zaretskii wrote:
> On Sun, 19 Jul 1998, Richard Lanyon wrote:

> > > In which object file (of the two you are linking) is `main' defined?

> > dsweep.o

> What was the exact GCC command used to compile dsweep.o?

gcc -Wall -c dsweep.c
(well, actually it's gcc $(FLAGS) -c $*.c, where the make target is
dsweep.o and FLAGS is -Wall)

> > > And why did you need those -L switches?

> > I'm trying to get my program to talk to a piece of hardware that's
> > connected to my computer. The libraries are provided by the hardware
> > manufacturer (TDT, hence they're in c:\tdt\...).

> But you aren't actually linking in any libraries from there, since there 
> are no -l switches on the GCC command line that you posted.  So, at least 
> in this case, those -L switches are redundant.

Aaaaaah! Good point - this explains something else that confused me. If I
ran the linker from the command line instead of via make, it didn't
complain about main being undefined, but /did/ complain about loads of the
hardware-specific functions being undefined.

Which leads to two questions:

i) how do I link to libraries if they aren't called lib??.o (or lib??.so).
Can I just rename them (they're libraries compiled using Borland Turbo
Pascal 2.0)? 

ii) why is make behaving so strangely?

Richard
love myself better than you
know it's wrong, what shall I do?