Code

 Header...
#define N 8
 int compared(const void *p1,const void *p2){
   ... 

»  static int called;
»  
»  int x1=*(int *)p1, x2=*(int *)p2;

»  ++called;
»  if (x1<x2) 
    return -1;
»  return x1>x2;
}

 int main(){
   ... 

»  int x[N]={8,6,3,5,7,1,4,2};
»  qsort(x, N, sizeof *x, compared);
»  
»  for ( int i=0;i<N; ++i) 
    printf("%d\n", xi);

»  return 0;
}