Question

I’m trying to get a small project compiled but am getting this error, I’ve been searching around and people get this error mainly because of incorrect file extension, but I don’t really think that’s the cause here:

gcc -c -W -Wall -ggdb -I. router.c -o router.o
router.c:106: warning: unused parameter ‘hname’
router.c: In function ‘flood_neighbors’:
router.c:464: warning: unused variable ‘bytes_rcvd’
router.c: At top level:
router.c:536: warning: unused parameter ‘fd’
gcc -c -W -Wall -ggdb -I. link_info.h -o link_info.o
gcc -c -W -Wall -ggdb -I. route.h -o route.o
gcc -c -W -Wall -ggdb -I. sequence.h -o sequence.o
gcc -W -Wall -ggdb -I. router.o link_info.o route.o sequence.o -o router
link_info.o: file not recognized: File format not recognized
collect2: ld returned 1 exit status
make: *** [router] Error 1

and my make file looks like:

CC = gcc
INC = -I.
FLAGS = -W -Wall -ggdb

router: router.o link_info.o route.o sequence.o
        $(CC) $(FLAGS) $(INC) $^ -o $@

router.o: router.c
        $(CC) -c $(FLAGS) $(INC) $< -o $@

sequence.o: sequence.h sequence.h
        $(CC) -c $(FLAGS) $(INC) $< -o $@

link_info.o: link_info.h link_info.c
        $(CC) -c $(FLAGS) $(INC) $< -o $@

route.o: route.h route.c
        $(CC) -c $(FLAGS) $(INC) $< -o $@

What I’m confused on is the rules for three object files are of the same format, but why only the link one yells? Thanks a lot!

Answer 1

I would like to suggest few edits in your makefile.

CC = gcc
INC = -I.
FLAGS = -W -Wall -ggdb

router: router.o link_info.o route.o sequence.o
        $(CC) $(FLAGS) $(INC) $^ -o $@

router.o: router.c
        $(CC) -c $(FLAGS) $(INC) $< -o $@

sequence.o: sequence.h sequence.h //Where is the c file ?
        $(CC) -c $(FLAGS) $(INC) $< -o $@

link_info.o: link_info.h link_info.c //Change the order. Put c file first and then the header
        $(CC) -c $(FLAGS) $(INC) $< -o $@

route.o: route.h route.c //Same as above
        $(CC) -c $(FLAGS) $(INC) $< -o $@