条件变量的陷阱，惊群效应（转载）

转自：http://originlee.com/2015/01/21/trick-in-conditon-variable/

 1 class ConditionBase
 2 {
 3 public:
 4     ConditionBase()
 5     {
 6         pthread_mutex_init(&mutex_, NULL);
 7         pthread_cond_init(&cond_, NULL);
 8     }
 9 
10     ~ConditionBase()
11     {
12         pthread_mutex_destroy(&mutex_);
13         pthread_cond_destroy(&cond_);
14     }
15 
16 private:
17     pthread_mutex_t  mutex_;
18     pthread_cond_t   cond_;
19 };
20 class Condition4 : public ConditionBase
21 {
22 public:
23     Condition4()
24         : signal_(false)
25     {
26     }
27 
28     void wait()
29     {
30         pthread_mutex_lock(&mutex_);
31         while (!signal_)
32         {
33             pthread_cond_wait(&cond_, &mutex_);
34         }
35         signal_ = false;
36         pthread_mutex_unlock(&mutex_);
37     }
38 
39     void wakeup()
40     {
41         pthread_mutex_lock(&mutex_);
42         signal_ = true;
43         pthread_cond_signal(&cond_);
44         pthread_mutex_unlock(&mutex_);
45     }
46 
47 private:
48     bool signal_;
49 };

 

附录：惊群效应

https://blog.csdn.net/lyztyycode/article/details/78648798