921113-1.c

this is a gcc file, you can download it and learn its usetility, for further detail please look at t

#define STACK_REQUIREMENT (128 * 128 * 4 + 1024)
#if defined (STACK_SIZE) && STACK_SIZE < STACK_REQUIREMENT
main () { exit (0); }
#else

typedef struct {
  float wsx;
} struct_list;

typedef struct_list *list_t;

typedef struct {
  float x, y;
} vector_t;

w(float x, float y) {}

f1(float x, float y)
{
  if (x != 0 || y != 0)
    abort();
}
f2(float x, float y)
{
  if (x != 1 || y != 1)
    abort();
}

gitter(int count, vector_t pos[], list_t list, int *nww, vector_t limit[2], float r)
{
  float d;
  int gitt[128][128];

  f1(limit[0].x, limit[0].y);
  f2(limit[1].x, limit[1].y);

  *nww = 0;

  d = pos[0].x;
  if (d <= 0.)
    {
      w(d, r);
      if (d <= r * 0.5)
	{
	  w(d, r);
	  list[0].wsx = 1;
	}
    }
}

vector_t pos[1] = {{0., 0.}};
vector_t limit[2] = {{0.,0.},{1.,1.}};

main()
{
  int nww;
  struct_list list;

  gitter(1, pos, &list, &nww, limit, 1.);
  exit(0);
}

#endif