The search begins at entry number \a offset; use an offset of 0 to
search from the beginning of the comment array.
\param object A pointer to an existing VORBIS_COMMENT object.
\param offset The offset into the comment array from where to start
the search.
\param field_name The field name of the comment to find.
\assert
\code object != NULL \endcode
\code object->type == FLAC__METADATA_TYPE_VORBIS_COMMENT \endcode
\code field_name != NULL \endcode
\retval int
The offset in the comment array of the first comment whose field
name matches \a field_name, or \c -1 if no match was found.
Find a Vorbis comment with the given field name.
The search begins at entry number \a offset; use an offset of 0 to search from the beginning of the comment array.
\param object A pointer to an existing VORBIS_COMMENT object. \param offset The offset into the comment array from where to start the search. \param field_name The field name of the comment to find. \assert \code object != NULL \endcode \code object->type == FLAC__METADATA_TYPE_VORBIS_COMMENT \endcode \code field_name != NULL \endcode \retval int The offset in the comment array of the first comment whose field name matches \a field_name, or \c -1 if no match was found.