How to install/compile SDL2 C code on Linux/Ubuntu

Question

I'm currently doing some C programming and I actually want to use the SDL library. I want to build a Small 2D game in C on Linux to sharp my skills a bit.

My issue is I'm not a super Makefile user nor library on Linux super user, I just configure things once when on a project and that's it.

So I have some trouble compiling SDL2 programs on UBUNTU 14.04.

I downloaded the latest SDL library from : http://www.libsdl.org/download-2.0.php

Then I installed it with the default step:

./configure
make
sudo make install

After that I can see that there is something in /usr/include/SDL2 so I guess it is installed.

#include <stdlib.h>
#include <stdio.h>
#include <SDL2/SDL.h>

int main(int argc, char *argv[])
{
 printf(“SDL test\n”);
    return 0;
}

Because I'm still learning Makefiles and SDL I didn't figure it out to make it.

but I found this Makefile to compile the old SDL not the SDL2

CPP=gcc   
CFLAGS=-O3 
LDFLAGS=-lSDL -lSDL_mixer #Linker
EXEC=test 

all: ${EXEC}

${EXEC}: ${EXEC}.o
    ${CPP} $(CFLAGS) -o ${EXEC} ${EXEC}.o ${LDFLAGS}

${EXEC}.o: ${EXEC}.c
    ${CPP} $(CFLAGS) -o ${EXEC}.o -c ${EXEC}.c


clean:  
    rm -fr *.o

mrproper: clean
    rm -fr ${EXEC}

But this Makefile is not working for me it says that it doesn't know the lSDL_Mixer and other stuff.

How can I build a workable Makefile to compile C program with SDL2 using Makefiles and vim editor.

Thanks in advance for your help

Answer 1

I'll go ahead and clean up that Makefile for you.

CFLAGS = -O3
LDFLAGS =
appname = test

all: $(appname)
clean:
    rm -f $(appname) *.o
.PHONY: all clean

sdl_cflags := $(shell pkg-config --cflags sdl2 SDL2_mixer)
sdl_libs := $(shell pkg-config --libs sdl2 SDL2_mixer)
override CFLAGS += $(sdl_cflags)
override LIBS += $(sdl_libs)

$(appname): test.o
    $(CC) $(LDFLAGS) -o $@ $^ $(LIBS)

Explanation

• Variables in a makefile should be used with $(...), not ${...}.

• pkg-config has an entry for SDL_Mixer, sdl-config does not. pkg-config is much more general.

• using override with the SDL flags allows you to run something like make CFLAGS="-O0 -g" without breaking SDL support.

• This is actually important: the SDL library flags have to be at the end of the command line, in LIBS, due to the fact that the GNU linker is sensitive to the order in which libraries are specified.

• You don't need explicit rules for .c files, because GNU Make has implicit rules which are just fine.

Note that there are some very important features missing from this makefile. For example, it won't automatically recompile things when you change your header files. I would recommend that you use another build system, such as CMake or SCons, which handles this automatically. You can also do it with Make, but you'd have to paste several arcane lines of code into your makefile.

Answer 2

You can use sdl2-config as suggested by the SDL Linux FAQ to get the required compiler and linker flags:

SDL_CFLAGS := $(shell sdl2-config --cflags)
SDL_LDFLAGS := $(shell sdl2-config --libs)

CFLAGS := $(SDL_CFLAGS) -O3
LDFLAGS := $(SDL_LDFLAGS) -lSDL_mixer

It will find the location of your SDL.h and return the corresponding flag (e.g. -I/usr/include/SDL2 in your case) among other flags it deems necessary (e.g. for me it gives -D_THREAD_SAFE). And then you can simply #include <SDL.h>, which is the standard way to include SDL.