# 2.5.11 条件变量类型

条件变量是一个设备，这个设备提供了更复杂的线程同步控制。线程可以在一个条件变量处阻塞，直到其他线程通知这个条件变量。

条件变量没有读取语法。它们的打印表示才有哈希记法，其中包含了条件变量的名称（如果有的话）或者其在核心内的地址：

```
(make-condition-variable (make-mutex))
    => #<condvar 01c45ae8>
```


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