bool

       MongoDB, Inc

       2009-present, MongoDB, Inc.

1.30.4                                            Jun 08, 2025                               BSON_APPEND_ITER(3)

       Appends the value at the current position of iter to the document.

       • bson: A bson_t.

       • key: Optional field name. If NULL, uses bson_iter_key(iter).

       • key_length: The length of key or -1 to use strlen().

       • iter: A bson_iter_t located on the position of the element to append.

       Returns  true  if  successful; false if the operation would overflow the maximum document size or another
       invalid state is detected.

          bool
          bson_append_iter (bson_t *bson,
                            const char *key,
                            int key_length,
                            const bson_iter_t *iter);