LinuxQuestions.org - undefined reference to `SDL

- Programming (https://www.linuxquestions.org/questions/programming-9/)

- - undefined reference to `SDL_Quit' (https://www.linuxquestions.org/questions/programming-9/undefined-reference-to-%60sdl_quit-604442/)

undefined reference to `SDL_Quit'

/tmp/ccSHyKZe.o: In function `main':
mouse.c:(.text+0x27): undefined reference to `SDL_Init'
mouse.c:(.text+0x4b): undefined reference to `SDL_SetVideoMode'
mouse.c:(.text+0x9d): undefined reference to `SDL_Quit'
collect2: ld returned 1 exit status

Anyone know why I might get an error of undefined reference to SDL_Init, SDL_SetVideoMode, and SDL_Quit... even though I have

#include <SDL/SDL.h>

with the correct path to the file in my code.

Are you linking the library as well?

I am trying to compile the code below on Fedora Core 6 [even tried Fedora Core 7] with the command

gcc -lX11 -L/usr/X11R6/lib -I/usr/X11R6/include -o go.exe mouse.c

Code:

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <X11/Xlib.h>

#include <SDL/SDL.h>



int main()

{

        int Quit=0;

        SDL_Event event;

        SDL_Init(SDL_INIT_VIDEO);

        SDL_SetVideoMode(320,200,0,0);



        typedef union

        {

                Uint8 type;

                SDL_ActiveEvent active;

                SDL_KeyboardEvent key;

                SDL_MouseMotionEvent motion;

                SDL_MouseButtonEvent button;

                SDL_JoyAxisEvent jaxis;

                SDL_JoyBallEvent jball;

                SDL_JoyHatEvent jhat;

                SDL_JoyButtonEvent jbutton;

                SDL_ResizeEvent resize;

                SDL_QuitEvent quit;

                SDL_UserEvent user;

                SDL_SysWMEvent syswm;

        } SDL_Event;

        SDL_MouseButtonEvent *button;



        while(!Quit){

                switch(event.type) {

                        case SDL_KEYDOWN:

                        case SDL_KEYUP:

                        case SDL_MOUSEMOTION:

                        case SDL_MOUSEBUTTONDOWN:

                        case SDL_MOUSEBUTTONUP:

                                printf("Mouse button %d released at (%d, %d)\n",

                                        button->button, button->x, button->y);

                                Quit=1;

                                break;

                        case SDL_JOYAXISMOTION:

                        case SDL_JOYHATMOTION:

                        case SDL_JOYBALLMOTION:

                        case SDL_JOYBUTTONDOWN:

                        case SDL_JOYBUTTONUP:

                                break;

                        default:

                                break;}}

        SDL_Quit();

        return(0);

}

Doesn't look like you're linking SDL, only X11. See the documentation for how to link the SDL library, it may just be a case of using -lsdl or something similar, or there may be a program that'll generate the required flags for you.

See the SDL FAQ's and this type of question is one that I hate the most, as it translates to "I am too lazy to look for myself, will someone else do it for me?"

[rant off]If you did not know this was a linker error then simply by ctrl-c and ctrl-v into google (example:undefined reference to `SDL_Init') and this would have brought a vast number of similar posts from other people. Some of which would give the same response as I(small rant) others would be more informative and supply links and answers.

My I also ask why you are redefining the SDL events?