title: How to deal with a missing key in a hashmap
body: <p>What might be a proper error or return code for when a <code>key</code> is asked for that cannot be returned?</p>
  <pre><code>void hash_delete(hash_table* table, const char* key)
  {
      hash_item* item = hash_get(table, key);
      if (item == NULL)
          ; // what error to raise?
      else
          delete_hash_item_internal(item);
  }
  </code></pre>
  <p>My thoughts were either to make the function return a <code>bool</code> instead (1=found, 0=not found), or do an <code>exit()</code>. What do you think would be a proper way to handle this?</p>