淺析C++智能指針和enable_shared_from_this機制

class ObjectPool:boost::noncopyable //為 class ObjectPool:public boost::enable_shared_from_this，
????????????????boost::noncopyable
{/*...*/};

第二處修改：

//改變 shared_ptrget(const string&?key) { /*...*/ shObject.reset(new Object(key),
?????????????????????boost::bind(&ObjectPool::deleteObject,this,_1)); /*...*/ } //為 shared_ptrget(const string&?key) { /*...*/ shObject.reset(new Object(key),
?????????????????????boost::bind(&ObjectPool::deleteObject,shared_from_this(),_1)); /*...*/ }

完整代碼：

#include class ObjectPool:public boost::enable_shared_from_this，
????????????????boost::noncopyable
{ public: shared_ptrget(const string&?key) { shared_ptrshObject; MutexLockGuard lock(mutex);
???weak_ptr&?wkObject=object[key];
???shObject=wkObject.lock();//對象存在，提升成功并返回 if(!shObject){ /*對象不存在，提升失敗，shOject重新指向新創(chuàng)建的
????Object對象，并綁定回調(diào)函數(shù)，讓對象Oject需要析構(gòu)時
????調(diào)用OjectPool對象的成員函數(shù)*/ shObject.reset(new Object(key),
??????????????????????boost::bind(&
??????????ObjectPool::deleteObject,shared_from_this(),
??????????_1));
??????wkObject=shObject;
???} return shObject;
} private: void deleteObject(Object*?obj) { /*回調(diào)函數(shù)，在對象需要析構(gòu)時調(diào)用，從map中刪除對象和對
應(yīng)的key*/ if(obj){ MutexLockGuard lock(mutex);
?????object.erase(obj->key());
????} delete obj;
} mutable MutexLock?mutex; std::map<string,weak_ptr>?object; /*map中不能使用shared_ptr，這會導(dǎo)致Oject對象永遠不會被銷
毀*/ };

小牛：不錯不錯，這下懂了 shared_ptr和 weak_ptr結(jié)合的用法了吧。