如何操作這個界面？

我已經看到了多種多線程和鎖的接口。如何操作這個界面？

這讓我感到沮喪，

一些包括2個不同的類，如下面的示例，而

別人只有一個類和獲取（）可以實現等待功能。

我的問題是：爲什麼我們在面向對象編程中設計這樣的鎖？

如何操作這些對象？

class Lock 
{ 
public: 
    Lock(); 
    ~Lock(); 

    // Acquire the lock. 
    void 
    acquire() 
    { this->lock_->acquire(); } 

    // Release the lock. 
    void 
    release() 
    { this->lock_->release(); } 

    private: 
    // This class can not be copied. 
    Lock(const Lock&); 
    Lock& operator=(const Lock&); 

    friend class Condvar; 
    Lock_impl* 
    get_impl() const 
    { return this->lock_; } 

    Lock_impl* lock_; 
}; 

class Condvar 
{ 
public: 
    Condvar(Lock& lock); 
    ~Condvar(); 
    // Wait for the condition variable to be signalled. This should 
    // only be called when the lock is held. 
    void 
    wait() 
    { this->condvar_->wait(this->lock_.get_impl()); } 

    // Signal the condition variable--wake up at least one thread 
    // waiting on the condition variable. This should only be called 
    // when the lock is held. 
    void 
    signal() 
    { this->condvar_->signal(); } 

    // Broadcast the condition variable--wake up all threads waiting on 
    // the condition variable. This should only be called when the lock 
    // is held. 
    void 
    broadcast() 
    { this->condvar_->broadcast(); } 

    private: 
    // This class can not be copied. 
    Condvar(const Condvar&); 
    Condvar& operator=(const Condvar&); 

    Lock& lock_; 
    Condvar_impl* condvar_; 
};

來源

2009-06-07 Kim