foo = get_foo();
if (foo) {
  bar = get_bar();
  if (bar) {
    /* do shit with foo & bar */
    put_bar(bar);
  }
  put_foo(foo);
}

void do_cool_shit() {
  Foo *foo = get_foo();  /* foo must be released when not needed */
  /* here we do shit with foo that may fail */
  Bar *bar = get_bar();  /* also must be released */
  /* here we do some other shit with foo & bar that may fail */
  /* ok now we're done */
  put_bar(bar);
  put_foo(foo);
}

typedef int (*worker_fn)(Foo *, Bar *);
int do_work(Foo *foo, Bar *bar);

int with_foo_and_bar(Foo *foo, worker_fn worker) {
  Bar *bar = get_bar();
  if (!bar)
    return -ESHITHAPPENED;
  int result = worker(foo, bar);
  put_bar(bar);
  return result;
}

int with_foo(worker_fn worker) {
  Foo *foo = get_foo();
  if (!foo)
    return -ESHITHAPPENED;
  int result  = with_foo_and_bar(foo, worker);
  put_foo(foo);
  return result;
}
/* ... */
with_foo(do_work);