qsort and bsearch over an array of pointers

bsearch.c

#include <stdio.h>
#include <stdlib.h>

struct foo {
  int count;
  const char *misc;
};

typedef struct foo * pfoo;

struct foo *foo_new(int c, const char *m);
int foo_cmp(const void *a, const void *b);

int main() {
  /* Let's suppose we allocate a dynamic array with a given size */
  void **ary = malloc(3*sizeof(void *));
  ary[0] = foo_new(4, "mac");
  ary[1] = foo_new(1, "linux");
  ary[2] = foo_new(9, "windows");

  /* Sort by increasing `count`-s */
  qsort(ary, 3, sizeof(void *), foo_cmp);

  /* Now let's retrieve item by count (= search key) */
  struct foo f1 = {.count = 4};
  struct foo f2 = {.count = 7};

  /* bsearch key (1st param) must be of *same* type than array elements! */
  struct foo *pf1 = &f1;
  struct foo **res1 = bsearch(&pf1, ary, 3, sizeof(void *), foo_cmp);
  printf("search #1 (key = %d) -> %s\n", f1.count, res1 ? "found": "not found");

  struct foo *pf2 = &f2;
  struct foo **res2 = bsearch(&pf2, ary, 3, sizeof(void *), foo_cmp);
  printf("search #2 (key = %d) -> %s\n", f2.count, res2 ? "found": "not found");

  free(ary[0]);
  free(ary[1]);
  free(ary[2]);
  free(ary);

  return 0;
}

struct foo *foo_new(int c, const char *m) {
  struct foo *f = malloc(sizeof(*f));
  f->count = c;
  f->misc = m;
  return f;
}

int foo_cmp(const void *a, const void *b) {
  const pfoo *A = a;
  const pfoo *B = b;
  return ( (*A)->count - (*B)->count );
}

Thanks for documenting this!