code:wflushtty - ikarishinjieva/unixV6-code-analyze-chs GitHub Wiki

8216 /* Wait for output to drain, then flush output waiting. */

8217 wflushtty(atp)

8218 struct tty *atp;

8219 {

8220 register struct tty *tp;

8221 tp = atp;

8222 spl5();

处理机优先级设为5

防止有新的输出字符进入

8223 while (tp->t_outq.c_cc) {

8224 tp->t_state =| ASLEEP;

8225 sleep(&tp->t_outq, TTOPRI);

8226 }

等待输出队列元素全部输出

等待时睡眠

睡眠原因 : struct clist

睡眠优先级 : TTOPRI

8227 flushtty(tp);

清空 tty 队列

8228 spl0();

开中断

8229 }

8230 /* ------------------------- */