Can't compile a file with SDL library linked on Ubuntu

Question

We have an assignment to compile a file with SDL library linked. The file itself shouldn't contain any errors since almost everyone managed to compile it. I've installed SDL 1.2 on Ubuntu 12.04 with the following commands:

sudo apt-get install libsdl1.2-dev
sudo apt-get install libsdl-image1.2-dev 
sudo apt-get install libsdl-mixer1.2-dev 
sudo apt-get install libsdl-ttf2.0-dev

I'm compiling it with the following command:

gcc -o sdl_introduction  sdl_introduction.c `sdl-config --cflags --libs`

I'm using with gcc 4.6.3
and I'm getting this error:

/usr/local/lib/libSDL.so: undefined reference to `_XGetRequest'
collect2: ld returned 1 exit status

What could cause the problem?

Answer 1

I have faced the same problem as you, it is caused by the SDL library needing other libraries to link with on ubuntu(or linux generally)

I recommend copiling it with :

gcc -o sdl_introduction  sdl_introduction.c -lX11 -pthread `sdl-config --cflags --libs`

Notice the added -lX11 and -pthread.

EDIT:

My bad I forgot that you must add -lX11 and -pthread after the other flags. Resulting in:

gcc -o sdl_introduction  sdl_introduction.c `sdl-config --cflags --libs` -lX11 -pthread