error message : linker input file unused since linking not done

["Thomas Singleton [Eidos]" <singleton at skynet dot be>]

hello,
in order to follow a book's test procedure to see if the compiling/linking
of C programs work, i created a hello.c
file with the famous 'printf("Hello World!");' then (always following the
instructions) did :
$gcc -c -Wall -D_GNU_SOURCE hello.c -o hello.o
then
$gcc -c hello.o hello.c
which reported :
gcc: hello.o : linker input file unused since linking not done

i made a search for that message on gcc.gnu.org, and found a few linked
messages but they were all about merging two or more source into the same
object which is not my case, so i decided to post this

Thank you for any advices
Thomas

i'm using RH 6.0 with kernel 2.2.5-15 and gcc --version reported :
egcs-2.91.66