How to implement readers-writer lock with timeout, a hard question.

[Chen （陈） Jun （军）]

Chen（陈）Jun（军） 写道:
>
> I look into the definition of pthread_rwlock_timedrdlock, there is a 
> mysterious lll_futex_timed_wait to carry out the wait operation. And 
> in pthread_rwlock_unlock, there is lll_futex_wake to do the wakeup. 
> What are those futex operations, are they documented somewhere?
>
>
Oh, I've found futex document in Linux man pages, thanks.