Error /usr/bin/ld "undefined reference to" Makefile in linux

[davilanxon]

Hello,

I am trying to compile this library in Ubuntu 20.04 but when I try it, I have these errors:

/usr/bin/ld: src/so_long.o: in function `main':
/home/david/Desktop/42Cursus/so_long_MLX/src/so_long.c:32: undefined reference to `mlx_init'
/usr/bin/ld: /home/david/Desktop/42Cursus/so_long_MLX/src/so_long.c:33: undefined reference to `mlx_key_hook'
/usr/bin/ld: /home/david/Desktop/42Cursus/so_long_MLX/src/so_long.c:37: undefined reference to `mlx_loop'

I have this makefile, and of course, I have included MLX42.h in my main.c:

NAME	= so_long

LIBMLX = ./lib/MLX42

LIBFT = ./lib/libft

HEADERS = -I ./includes -I $(LIBMLX)/include -I $(LIBFT)

SRCS	= src/so_long.c src/ft_get_dimensions.c #src/ft_show_map.c

OBJS	= $(SRCS:.c=.o)

CC	= gcc

RM	= rm -f

CFLAGS	= -Wall -Wextra -Werror -Iincludes -g

LIBS = -lglfw -ldl -L $(LIBMLX)/libmlx42.a $(LIBFT)/libft.a

%.o: %.c
	@$(CC) $(CFLAGS) -o $@ -c $< $(HEADERS)

all: $(NAME)

$(NAME):	$(OBJS)
			make -C lib/MLX42/ all
			make -C lib/libft/ all
			$(CC) $(OBJS) $(LIBS) $(HEADERS) -o $(NAME)


clean: 
		$(RM) $(OBJS)
		make -C lib/MLX42/ clean
		make -C lib/libft/ clean

fclean: clean
		$(RM) $(NAME)
		make -C lib/MLX42/ fclean
		make -C lib/libft/ fclean

re:	fclean all

.PHONY:	all clean fclean re

I don't know why it fails.
Thank you very much!

[davilanxon]

For anyone who have problems compiling in linux, this makefile works:

NAME	= so_long

LIBMLX = lib/MLX42/libmlx42.a

LIBFT = lib/libft/libft.a

SRCS	= src/so_long.c

OBJS	= $(SRCS:.c=.o)

CC	= gcc

RM	= rm -f

CFLAGS	= -Wall -Wextra -Werror -Iincludes -g

MLX_FLAGS = -ldl -lglfw

all: $(NAME)

$(NAME):	$(OBJS)
			make -C lib/MLX42/ all
			make -C lib/libft/ all
			$(CC) $(CFLAGS) $(OBJS) $(LIBFT) $(LIBMLX) $(MLX_FLAGS) -o $(NAME) 


clean: 
		$(RM) $(OBJS)
		make -C lib/MLX42/ clean
		make -C lib/libft/ clean

fclean: clean
		$(RM) $(NAME)
		make -C lib/MLX42/ fclean
		make -C lib/libft/ fclean

re:	fclean all

.PHONY:	all clean fclean re

[W2Wizard]

Yeah so in some cases, -ldl has to go BEFORE -lglfw, in my ZorinOS distro this fixed my issue once, very strange.