检查pthread_rwlock_t的状态

问题描述

我正在修改我编写的一些代码，并且遇到了这种情况:我应该写出能做以下事情的东西

Hi,
I''m revising some code i wrote and i''ve this scenario: i should write something that does the following

If a pthread_rwlock_t is not in use (i mean, no one holds it, and no one is waiting for it)
      destroy it

现在，我该怎么做检查?我的意思是，我认为pthread_rwlock_t的不同实现具有不同的结构字段(在我的系统上，pthread_rwlock_t是联合tbh，我认为该类型没有标准)，所以我应该通过pthread函数来实现，但是如何?我还发现，如果您在繁忙" rwlock上调用破坏"，则它不是标准行为(繁忙"是指有人拿着它或有人在等待它)
我怎样才能做到这一点?我唯一的想法是使用这样的结构

Now, how can i do this check? I mean, i think that different implementations of pthread_rwlock_t have different structure fields (on my system, pthread_rwlock_t is a union tbh, i think there isn''t a standard for the type), so i should do it through pthread functions, but how? Also i found out that "destroy" has not a standard behaviour if you call it on a "busy" rwlock (with busy, i mean that someone holds it or someone is waiting for it)

How can i do this? The only idea i have is using a struct like this

struct MyLock
{
  pthread_rwlock_t l;
  int waiting;
}

在调用rdlock或wrlock之前增加每次等待的时间，并在我每次获取该锁之前增加其等待的时间，然后我可以检查是否可以销毁它，除非且仅当我获得对它的排他锁(这意味着没有人持有它)且等待时间为零..还有其他不需要我计算等待线程数的想法吗?

increase waiting everytime before calling rdlock or wrlock and deacreasing everytime i acquire the lock, and then i could check if i can destroy it if and only if i acquire the exclusive lock on it (that means no one is holding it) and waiting is zero.. any other ideas that don''t require me to count the threads waiting?

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