class ConditionBase
{
public:
    ConditionBase()
    {
        pthread_mutex_init(&mutex_, NULL);
        pthread_cond_init(&cond_, NULL);
    }
 
    ~ConditionBase()
    {
        pthread_mutex_destroy(&mutex_);
        pthread_cond_destroy(&cond_);
    }
 
private:
    pthread_mutex_t  mutex_;
    pthread_cond_t   cond_;
};