[SDL] sdl freesurface causing seg faults when blitting.

[CWC]

>     SDL_BlitSurface(surfaces[id].s,NULL,screen,&surfaces[id].coords);        //seg faults here!!!

Of course a seg fault is caused by illegal access to memory, and this 
line includes 4 pointers ... one of them is invalid.

NULL can be ruled out, so the trick would be to break out the other 
three pointers onto separate lines.

You could try:
SDL_BlitSurface(surfaces[id].s,
                 NULL,
                 screen,
                 &surfaces[id].coords);

and possibly get the segfault to identify the one it doesn't like. If 
your compiler optomizes away the distinction, you could try:

SDL_Rect tempRect;
  = &surfaces[id].coords;

SDL_Surface *tempSurface = surfaces[id].s;

tempRect.x = tempRect.y = 0;
temprect.w = surfaces[id].coords.w // If it blows up here, there's
                        //something wrong with &surfaces[id].coords
tempRect.h = surfaces[id].coords.h;

if ((tempSurface->w != tempRect.w) ||
     (tempSurface->h != tempRect.h))
{
     cerr << "Gotcha, bad pointer : surfaces[id].s";
     exit (-1);
}

SDL_BlitSurface(tempSurface,NULL,screen,&tempRect);

===========

It's not intended to be production quality code, just explicit access to 
your pointers on separate lines to see which one is segfaulting.

If it still segfaults while blitting, check 'screen'.