undefined reference error in static libraries.

[Niklaus]

On 4/27/06, steven woody <narkewoody@gmail.com> wrote:
> hi, i am build a program, the structure of the source is below,
>
> main.o
>     main.c
>     libfoo.a
>         foo.c
>     libbar.a
>         bar.c
>

> and, the foo.c has a reference to function bar() which is defined in bar.c
>
> i can successfully compile and produce libfoo.a and libbar.a. but when
> compile main.o, i get an error like following:
>
> gcc -g -O2 -o main.o main.o libfoo.a libbar.a

it should be -o a.out or something like that because main.o is overwritten.
Please paste the code
>
> libfoo.a(libfoo_a-foo.o): in function 'foo':
> foo.c: undefined reference to 'bar'
>
>
> what's the cause and how do i do? thanks.
>
> --
> woody
>