Always returns true.
odbc_free_result() only needs to be called if you are worried about using too much memory while your script is running. All result memory will automatically be freed when the script is finished. But, if you are sure you are not going to need the result data anymore in a script, you may call odbc_free_result(), and the memory associated with result_id will be freed.
Note: If auto-commit is disabled (see odbc_autocommit()) and you call odbc_free_result() before commiting, all pending transactions are rolled back.