ne</i>, as far as they are not NULL. An unset filename is indicated as &quot;&quot;, i.e., an empty string. An unset line number is indicated as 0.</p>

<p>ERR_peek_error_func() and ERR_peek_last_error_func() are the same as ERR_peek_error() and ERR_peek_last_error(), but on success they additionally store the name of the function where the error occurred in *<i>func</i>, unless it is NULL. An unset function name is indicated as &quot;&quot;.</p>

<p>ERR_peek_error_data() and ERR_peek_last_error_data() are 