MySQL 5.6 C API Developer Guide
MYSQL_FIELD_OFFSET mysql_field_seek(MYSQL_RES *result, MYSQL_FIELD_OFFSET offset)
Sets the field cursor to the given offset. The next call to
mysql_fetch_field()
retrieves
the field definition of the column associated with that
offset.
To seek to the beginning of a row, pass an
offset
value of zero.