[SDL] dynamic memory allocation and SDL_Surfaces

[matt]

perhaps you could post an example, that was hard to follow.

matt

On Wed, 5 Sep 2007 20:29:32 +0000 (UTC)
Chris Dickinson <cdickins at udel.edu> wrote:

> I have a question about freeing pointers to surfaces - I'm trying to
> figure out whether my program might have a memory leak.  In one
> function, I use malloc () to create a pointer to an array of
> SDL_Surfaces. I then load various images onto the surfaces and pass a
> pointer to the array to a second function.  In the second function, I
> use malloc() to create a second array of pointers to SDL_Surfaces,
> and I use this array to access the surfaces passed to the function (I
> know that on the surface this sounds odd, but within the program
> there is a good reason for doing this).  After the called function
> returns, I free each of the surfaces in the array [i.e., for (i=0;
> i<nSurfaces; i++) SDL_FreeSurface(surface1[i])] and then free the
> pointer [free(surface1)].  If I do this, but don't attempt to free
> the pointers created in the second function, the program works as it
> should, and I don't see any obvious evidence of memory leaks.  If in
> the function that is called I try to free the pointers to the
> individual surfaces that were allocated with the call to malloc()
> [i.e., for (i=0; i<nSurfaces; i++) SDL_FreeSurface(surface2[i])], I
> get a seg fault (which is expected).  If, however, I simply free the
> pointer [i.e., free (surface2)], I don't get a seg fault.  My
> question is whether I need to free the pointer of SDL_Surfaces
> allocated in the called function or not (and if not freeing it will
> result in a memory leak).  I know that if I were passing a pointer to
> a single surface and then accessing it with another pointer, freeing
> both would cause a seg fault (only the pointer to the original
> surface should be freed - the one that was passed).  If anyone has
> any thoughts, they would be greatly appreciated.  If it matters, I'm
> coding in C (MS C++ 6.0 Professional).  Thanks.
> 
> Regards,
> 
> Chris Dickinson, PhD
> Department of Psychology
> University of Delaware
> 
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