请问调用rt_thread_create（）创建线程，初始化定时器有何用处

choose521

调用rt_thread_create（）创建线程的时候，调用了下面的代码，作用是什么？

/* initialize thread timer */
* Q- H# L$ A& G6 _2 r2 j* p, `rt_timer_init(&(thread->thread_timer),thread->name,rt_thread_timeout,thread,0,RT_TIMER_FLAG_ONE_SHOT);
为什么要创建这个定时器？
" i$ Q5 U8 s. s1 l+ E  C
在系统时钟中断回调函数里面，已经调用了下面的代码

void rt_tick_increase(void)
{
- v4 }# ?  T, q# R: H/ g2 F, g$ z' fstruct rt_thread thread;
/ increase the global tick /
++ rt_tick;
/ check time slice /
thread = rt_thread_self();
-- thread->remaining_tick;
. }: g' a8 ?* `0 [  |if (thread->remaining_tick == 0)
{
/ change to initialized tick /
/ U1 W4 \2 f0 a8 kthread->remaining_tick = thread->init_tick;
/ yield /
rt_thread_yield();
}
0 Y+ ^3 [% a  t( X4 c8 @4 L/ check timer */
; l- ?  w6 u0 Y( ?: O  D4 Vrt_timer_check();
}
上面的代码已经会去判断remaining_tick，这个为0就执行让出cpu操作了。
# s' K$ ?: a6 U0 M2 S7 e

opipo

用来控制挂起时间的。例如你主动调用delay或者阻塞于获取信号量等都会用到这个定时器。截取了一段信号量获取函数中的源码：
`
/ start /
rt_ipc_list_suspend(&(sem->parent.suspend_thread),
4 H% \+ e1 W* k0 rthread,
sem->parent.parent.flag);
+ W' [* c, y' [3 g" _( M" h
- y. `. c! B. o) k/ T$ x+ V/* has waiting time, start thread timer */
if (time > 0)
{
RT_DEBUG_LOG(RT_DEBUG_IPC, ("set thread:%s to timer list\n",
thread->name));
9 N9 H/ R! j. Q9 S8 \/* reset the timeout of thread timer and start it */
rt_timer_control(&(thread->thread_timer),
RT_TIMER_CTRL_SET_TIME,
&time);
% L! N4 b  Y! |" U. \+ [* brt_timer_start(&(thread->thread_timer));
}
/* enable interrupt */
rt_hw_interrupt_enable(temp);
/* do schedule */
/ R( X. O* F* @1 _/ }8 Rrt_schedule(); rt_ipc_list_suspend(&(sem->parent.suspend_thread),
thread,
sem->parent.parent.flag);
3 `; s8 G+ H" z0 {) v" L/* has waiting time, start thread timer */
if (time > 0)
{
RT_DEBUG_LOG(RT_DEBUG_IPC, ("set thread:%s to timer list\n",
thread->name));
/* reset the timeout of thread timer and start it */
rt_timer_control(&(thread->thread_timer),
8 ]3 T* d: O$ y4 m" R+ KRT_TIMER_CTRL_SET_TIME,
&time);
$ {) y/ ^0 W2 E+ b! S' t. S  F4 r! krt_timer_start(&(thread->thread_timer));
3 C4 t1 i; s) L4 K}
/* enable interrupt */
4 j6 F5 \# i& o  v* zrt_hw_interrupt_enable(temp);
/* do schedule */
3 R( P6 r* E" h1 c7 A- Xrt_schedule();`
: ^3 Y3 f- m" W* `: u

Blah

楼上说的很不错的

land

可以试试一楼的方法