SDL is installed, included and linked, but will not compile SDL code

mansizerooster · 05-20-2006, 12:10 PM

Hi all,

I have been trying to get a nice fullscreen app with GLUT, but have had no luck as gamemode is not supported for my X.

I have decided to try my luck with SDL, and so have installed it, have included it in my program with:

#include "SDL/SDL.h"

and have linked with my makefile as so (glut is still there so i don't need to strip it all out my code):

g++ -O0 -L/usr/X11R6/lib/ -lglut `sdl-config --cflags --libs` -lGL -lGLU src/Main.o -o demo

Now, this compiles and runs nicely before I add any sdl-specific code to my program, but as soon as I enter

SDL_Init(SDL_INIT_EVERYTHING);

I get this error:

Main.cpp

.text+0x11da): undefined reference to `SDL_Init'

I don't understand what is going wrong, as I have installed, included it and linked it with my program. Could anybody please help point me towards where I am going wrong?

Thanks in advance.

zackarya · 05-20-2006, 01:07 PM

I believe you need to add -lSDL.

-lSDL flag tells gcc to link the libSDL.so shared library in with your program.

Hope that helps.

Zackarya

mansizerooster · 05-21-2006, 06:48 AM

Quote:

Originally Posted by zackarya

I believe you need to add -lSDL.

-lSDL flag tells gcc to link the libSDL.so shared library in with your program.

Hope that helps.

Zackarya

The `sdl-config --cflags --libs` is equivelant to that. I get the same error even when I actually do use -lSDL as well.

xhi · 05-21-2006, 11:22 PM

yeh that looks like it should work.

run sdl-config by itself and see what paths its using and make sure they match up with what is actually on your system..

Dark_Helmet · 05-21-2006, 11:33 PM

Did you run ldconfig after you installed SDL?

mansizerooster · 05-22-2006, 03:50 PM

Quote:

Originally Posted by Dark_Helmet

Did you run ldconfig after you installed SDL?

Yes, I have done that, but still no luck. I'm really stumped on this one.

tuxdev · 05-22-2006, 07:03 PM

Use #include "SDL.h", not #include "SDL/SDL.h". The SDL docs will confirm it.
For most anything, compile the separate .o files before linking because it helps with not having to recompile the whole file just because of a linker error.
Sample makefile that I use for one of my play programs.

Code:

CC = gcc
CFLAGS = `sdl-config --cflags` -g -Wall
all: maze
maze: maze.o
&tab;$(CC) `sdl-config --libs` -o maze maze.o

mansizerooster · 05-23-2006, 12:37 AM

Quote:

Originally Posted by tuxdev

Use #include "SDL.h", not #include "SDL/SDL.h". The SDL docs will confirm it.
For most anything, compile the separate .o files before linking because it helps with not having to recompile the whole file just because of a linker error.
Sample makefile that I use for one of my play programs.

Code:

CC = gcc
CFLAGS = `sdl-config --cflags` -g -Wall
all: maze
maze: maze.o
&tab;$(CC) `sdl-config --libs` -o maze maze.o

I tried this, but to no avail. Interestingly, the error I got may shed some light on the problem. When i change my #include to "SDL.h" instead of "SDL/SDL.h", I got this error:

src/Main.cpp:8:17: error: SDL.h: No such file or directory
src/Main.cpp: In function 'int main(int, char**)':
src/Main.cpp:237: error: 'SDL_INIT_EVERYTHING' was not declared in this scope
src/Main.cpp:237: error: 'SDL_Init' was not declared in this scope

As opposed to the error I got with "SDL/SDL.h",

src/Main.o: In function `main':
Main.cpp

.text+0x11da): undefined reference to `SDL_Init'
collect2: ld returned 1 exit status

I think this shows that #include "SDL.h" works as it recognises SDL_INIT_EVERYTHING, just not the function it is used in.

Just an idea. And btw thanks everyone for trying to help me!

mansizerooster · 05-27-2006, 09:52 AM

Hey everyone,

This is still a problem with me, and a really annoying one at that. Anyone have any ideas what could be wrong? Is there any information I could be disclosing that would help?

Dark_Helmet · 05-30-2006, 07:13 PM

Well, I can try to compile it on my machine. You'll need to post some code for me to work with though.

EDIT:
Also, where are the libs for SDL installed? Did you install with a package manager or from source? If from source and you installed to a non-standard location, what does ld.so.conf contain?

Do you use a Makefile? What's in it?

dmail · 05-31-2006, 04:18 AM

Quote:

I get this error:

Main.cpp.text+0x11da): undefined reference to `SDL_Init'

What is the prototype for your main function?