Linking errors with SDL_mixer library

Question

I'm working with the SDL and SDL_mixer library and am getting the following errors when I compile:

....
game.cpp:(.text+0x88f): undefined reference to `Mix_OpenAudio'
Jukebox.o: In function `Jukebox::~Jukebox()':
Jukebox.cpp:(.text+0x17): undefined reference to `Mix_FreeChunk'
Jukebox.cpp:(.text+0x27): undefined reference to `Mix_FreeChunk'
Jukebox.cpp:(.text+0x37): undefined reference to `Mix_FreeChunk'
Jukebox.cpp:(.text+0x47): undefined reference to `Mix_FreeChunk'
....

And so on and so forth or all instances when I use a SDL_mixer function.

I'm fairly confident that the error lies within the Makefile because it compiles just fine in another test program I made.

My Makefile

SDL= -lSDL -lSDL_mixer

OBJ=game.o Jukebox.o ...

all:    main

main:   $(OBJ)
        g++ $(SDL) $(OBJ) -o main

%.o:    %.cpp
        g++ $(SDL) -c $<

clean:
        rm -f *.o *~ main
        rm -f */*~

Where is the error?

Answer 1

I think the problem is the order of your arguments.

Instead of

main:   $(OBJ)
        g++ $(SDL) $(OBJ) -o main

try

main:   $(OBJ)
        g++ -o main $(OBJ) $(SDL) 

While the position of -o main is not really important, the order of the link libraries is. Compilers resolve the symbols in the order the libraries appear on the command line.

Answer 2

It seems that you linker cannot find where the libraries are located. Identify where they were installed and pass this path to the linker via -L directive.

Put something like this: SDL= -L/path/to/installed/SDL/libraries -lSDL -lSDL_mixer

Note that, in: g++ $(SDL) -c $< the variable $(SDL) is irrelevant, once your are not linking into your program, but just generating the objects.