ST_OP_READ
un->un_lastop = ST_OP_READ;
new_lastop = ST_OP_READ;
un->un_lastop = ST_OP_READ;
if (un->un_lastop == ST_OP_READ && un->un_pos.eof == ST_EOF_PENDING) {
un->un_lastop = ST_OP_READ;
un->un_lastop = ST_OP_READ;