Make file problem?

Question

Why when i compile my program with my makefile I obtain that :

gcc -Wall -pedantic src/main.c -o _wk/main.o
src/main.c:9:11: warning: C++ style comments are not allowed in ISO C90
src/main.c:9:11: warning: (this will be reported only once per input file)
src/main.c: In function ‘initialiseStructItimerval’:
src/main.c:46: warning: format ‘%d’ expects type ‘int’, but argument 2 has type ‘__suseconds_t’
src/main.c: In function ‘stockeRetard’:
src/main.c:71: warning: ISO C90 forbids mixed declarations and code
src/main.c: In function ‘main’:
src/main.c:141: warning: ISO C90 forbids mixed declarations and code
src/main.c:139: warning: unused variable ‘i’
Debut de l'edition des liens...
cd _wk ; gcc -o ../test main.o
main.o: In function `_start':
(.text+0x0): multiple definition of `_start'
/usr/bin/ld: /usr/lib/debug/usr/lib/crt1.o(.debug_info): relocation 0 has invalid symbol index 12
/usr/bin/ld: /usr/lib/debug/usr/lib/crt1.o(.debug_info): relocation 1 has invalid symbol index 13
/usr/bin/ld: /usr/lib/debug/usr/lib/crt1.o(.debug_info): relocation 2 has invalid symbol index 2
/usr/bin/ld: /usr/lib/debug/usr/lib/crt1.o(.debug_info): relocation 3 has invalid symbol index 2
/usr/bin/ld: /usr/lib/debug/usr/lib/crt1.o(.debug_info): relocation 4 has invalid symbol index 12
/usr/bin/ld: /usr/lib/debug/usr/lib/crt1.o(.debug_info): relocation 5 has invalid symbol index 14
/usr/bin/ld: /usr/lib/debug/usr/lib/crt1.o(.debug_info): relocation 6 has invalid symbol index 14
/usr/bin/ld: /usr/lib/debug/usr/lib/crt1.o(.debug_info): relocation 7 has invalid symbol index 14
/usr/bin/ld: /usr/lib/debug/usr/lib/crt1.o(.debug_info): relocation 8 has invalid symbol index 2
/usr/bin/ld: /usr/lib/debug/usr/lib/crt1.o(.debug_info): relocation 9 has invalid symbol index 2
/usr/bin/ld: /usr/lib/debug/usr/lib/crt1.o(.debug_info): relocation 10 has invalid symbol index 13
/usr/bin/ld: /usr/lib/debug/usr/lib/crt1.o(.debug_info): relocation 11 has invalid symbol index 14
/usr/bin/ld: /usr/lib/debug/usr/lib/crt1.o(.debug_info): relocation 12 has invalid symbol index 14
/usr/bin/ld: /usr/lib/debug/usr/lib/crt1.o(.debug_info): relocation 13 has invalid symbol index 14
/usr/bin/ld: /usr/lib/debug/usr/lib/crt1.o(.debug_info): relocation 14 has invalid symbol index 14
/usr/bin/ld: /usr/lib/debug/usr/lib/crt1.o(.debug_info): relocation 15 has invalid symbol index 14
/usr/bin/ld: /usr/lib/debug/usr/lib/crt1.o(.debug_info): relocation 16 has invalid symbol index 14
/usr/bin/ld: /usr/lib/debug/usr/lib/crt1.o(.debug_info): relocation 17 has invalid symbol index 14
/usr/bin/ld: /usr/lib/debug/usr/lib/crt1.o(.debug_info): relocation 18 has invalid symbol index 14
/usr/bin/ld: /usr/lib/debug/usr/lib/crt1.o(.debug_info): relocation 19 has invalid symbol index 14
/usr/bin/ld: /usr/lib/debug/usr/lib/crt1.o(.debug_info): relocation 20 has invalid symbol index 14
/usr/bin/ld: /usr/lib/debug/usr/lib/crt1.o(.debug_info): relocation 21 has invalid symbol index 14
/usr/bin/ld: /usr/lib/debug/usr/lib/crt1.o(.debug_info): relocation 22 has invalid symbol index 22
/usr/bin/ld: /usr/lib/debug/usr/lib/crt1.o(.debug_line): relocation 0 has invalid symbol index 2
/usr/lib/gcc/i486-linux-gnu/4.4.3/../../../../lib/crt1.o:/build/buildd/eglibc-2.11.1/csu/../sysdeps/i386/elf/start.S:119: first defined here
main.o:(.rodata+0x0): multiple definition of `_fp_hw'
/usr/lib/gcc/i486-linux-gnu/4.4.3/../../../../lib/crt1.o:(.rodata+0x0): first defined here
main.o: In function `_fini':
(.fini+0x0): multiple definition of `_fini'
/usr/lib/gcc/i486-linux-gnu/4.4.3/../../../../lib/crti.o:(.fini+0x0): first defined here
main.o:(.rodata+0x4): multiple definition of `_IO_stdin_used'
/usr/lib/gcc/i486-linux-gnu/4.4.3/../../../../lib/crt1.o:(.rodata.cst4+0x0): first defined here
main.o: In function `__data_start':
(.data+0x0): multiple definition of `__data_start'
/usr/lib/gcc/i486-linux-gnu/4.4.3/../../../../lib/crt1.o:(.data+0x0): first defined here
main.o: In function `__data_start':
(.data+0x4): multiple definition of `__dso_handle'
/usr/lib/gcc/i486-linux-gnu/4.4.3/crtbegin.o:(.data+0x0): first defined here
main.o: In function `_init':
(.init+0x0): multiple definition of `_init'
/usr/lib/gcc/i486-linux-gnu/4.4.3/../../../../lib/crti.o:(.init+0x0): first defined here
/usr/lib/gcc/i486-linux-gnu/4.4.3/crtend.o:(.dtors+0x0): multiple definition of `__DTOR_END__'
main.o:(.dtors+0x4): first defined here
collect2: ld returned 1 exit status
make: *** [all] Erreur 1

My makefile is this :

CC=gcc
LD=gcc
C_FLAGS= -Wall -pedantic


#Dossier de workarea pour la generation
RWK=_wk

#Liste des dossier dans lesquels effectuer la recherche ordonnee
DIRS= \
src \
bin \
$(RWK)

#Definition de la liste des sources C a compiler
SRC_C=$(shell (for src in $$(find . -type f -name *.c) ; do basename $$src ; done))

#Liste des fichiers objets
C_OBJS=$(SRC_C:.c=.o)

vpath %.c $(DIRS)

#Regle principale
all: init_wk $(C_OBJS)
    @echo "Debut de l'edition des liens..."
    cd $(RWK) ; $(LD) -o test $(C_OBJS)
    @echo "Compilation terminee."

#Regle de generation des fichier c->o
%.o : %.c
    @echo "Compilation des .c : $<"
    $(CC) $(C_FLAGS) $< -o $(RWK)/$@

#Regle a appeler pour le nettoyage de RWK
clean:
    @echo "Nettoyage du dossier de travail"
    @if [ -d $(RWK) ] ; then rm -rf $(RWK) ; fi

#Regle d'initialisation de la workarea
init_wk: clean
    @echo "Creation du dossier de travail..."
    @mkdir $(RWK)
    @if [ -e ./out ]; then echo "Existe deja"; else mkdir ./out; fi

But when i try with a simple makefile like that and with no folder inclusion i've no errors:

CC=gcc
LD=gcc
BIN = hello
SRCS=$(wildcard *.c)
OBJS = $(SRCS:.c=.o)
DEPS = $(SRCS:.c=.d)
CFLAGS = -W -Wall -pedantic
all: $(BIN)
$(BIN): $(OBJS)
    $(LD) -o $@ $(OBJS)
%.o: %.c
    $(CC) -o $@ -c $< $(CFLAGS)
%.d: %.c
    $(CC) $(CFLAGS) -MM -MD -o $@ $<
-include $(DEPS)
.PHONY: clean distclean
clean:
    rm -rf $(OBJS)

Sorry for this long post but i don't understand my mistake :/

Answer 1

When compiling single modules only (not linking them), add -c as a compiler parameter to keep it from linking the c/c++ runtime every time.

When you'd like to get a executable or library file, don't add -c. If you'd like to get a .o file, add -c.

Answer 2

%.o : %.c
    @echo "Compilation des .c : $<"
    $(CC) $(C_FLAGS) $< -o $(RWK)/$@

There is a problem here: without the -c option, gcc will compile and link. Try with this:

    $(CC) $(C_FLAGS) -c $< -o $(RWK)/$@

Also, it is much more common to have $(CFLAGS) than $(C_FLAGS)