Linking SDL in a C program - c

Question

I have recently become interested in using SDL after having learned some basics of C. I have installed SDL_image and SDL_mixer. They are located in /usr/local/include/SDL2. I realize that you must link against the header files however I am not sure how to do it. I am getting the error that SDL_mixer or SDL_image do not exist (depending on their line order in my source code). I have tried two different compilation commands and neither work here they are:
gcc filename.c -o test -I./include -L./usr/local/include/SDL2 -lSDL2main -lSDL2 -lSDL_mixer -lSDL_image
gcc filename.c -o test -I./usr/local/include/SDL2 -L./lib -lSDL2main -lSDL2 -lSDL_mixer -lSDL_image
If anyone has any ideas I would appreciate it! Thanks in advance!

Answer 1

you do not want that leading period
wrong
gcc filename.c -o test -I./include -L./usr/local/include/SDL2 -lSDL2main -lSDL2 -lSDL_mixer -lSDL_image
closer - not necessarily correct yet
gcc filename.c -o test -L/usr/local/include/SDL2 -lSDL2main -lSDL2 -lSDL_mixer -lSDL_image
any path with a leading period indicates to start from current dir and go relative instead of the intended absolute path
any system has the notion of a default library path which is fine if you are using a standard install ... so no need to do a
-I/include
... sometime a library has helpers to identify and auto populate these ...
sdl and sdl2 do have such a helper ... this will give you those settings
gcc -o test filename.c `pkg-config --cflags --libs sdl2`
notice those backticks ... another syntax style would be
gcc -o test filename.c $(pkg-config --cflags --libs sdl2)
you are free to issue that stand alone just to take a peek
pkg-config --cflags --libs sdl2
... output
-D_REENTRANT -I/usr/include/SDL2 -lSDL2
Now onto your sdl mixer ... well it has a
pkg-config --cflags --libs SDL2_mixer
... output
-D_REENTRANT -I/usr/include/SDL2 -lSDL2_mixer -lSDL2
you probably do not want to mix sdl with sdl2 so replace mention of
-lSDL_mixer -lSDL_image
with
-lSDL2_mixer -lSDL2_image
as per
pkg-config --cflags --libs SDL2_image
... output
-D_REENTRANT -I/usr/include/SDL2 -lSDL2_image -lSDL2
so bundling these together
gcc -o test filename.c -lSDL2main $(pkg-config --cflags --libs sdl2) $(pkg-config --cflags --libs SDL2_mixer) $(pkg-config --cflags --libs SDL2_image)
or more simply combined to
gcc -o test filename.c -lSDL2main $(pkg-config --cflags --libs sdl2 SDL2_mixer SDL2_image )
this can be stripped down to simply the following ... yet above syntax is more robust to changes
gcc -o test filename.c -D_REENTRANT -I/usr/include/SDL2 -lSDL2main -lSDL2 -lSDL2_mixer -lSDL2_image

Answer 2

You can use sdl2-config to supply the appropriate flags to gcc:
gcc filename.c -o test `sdl2-config --cflags --libs`
sdl2-config --cflags produces a list of options that should be passed to the compiler, and sdl2-config --libs produces a list of libraries that should be linked to.