SDL segfault when trying to draw to screen

[Blizzarddog]

if ( SDL_Init(SDL_INIT_AUDIO|SDL_INIT_VIDEO) < 0 )
	{
		printf("Unable to init SDL: %s\n", SDL_GetError());
		exit(1);
	}
	atexit(SDL_Quit);
	screen=SDL_SetVideoMode(1024,768,32,SDL_HWSURFACE|SDL_DOUBLEBUF|SDL_FULLSCREEN);
	if ( screen == NULL )
	{
		printf("Unable to set video: %s\n", SDL_GetError());
		exit(1);
	}
	
	drawString(screen, font, 0, 0, "Loaded!\n");

It Segfaults at the drawString.

I've tried blitting surfaces to the screen and all, but it still segfaults whenever I try to draw to the screen.

[Blizzarddog]

I fixed it. It semms i wasn't initializeing certain objects.

[Quantum1024]

You need to lock/unlcok a surface before using it.

void render()
{   
 
 // Lock surface if needed
  if (SDL_MUSTLOCK(Screen))
    if (SDL_LockSurface(Screen) < 0) 
      return;

  //draw to screen here

  // Unlock if needed
    if (SDL_MUSTLOCK(Screen)) 
        SDL_UnlockSurface(Screen);

  // Tell SDL to update the whole gScreen
    SDL_UpdateRect(Screen, 0, 0, WIDTH, HEIGHT);    
}