如果我要自己写,我想我会做些类似的事情:
template<typename T, typename Dtor = std::default_delete<T> >
class Uptr : private Dtor {
T* vl_;
public:
explicit Uptr(T* vl = nullptr) noexcept : vl_(vl) {}
~Uptr() noexcept { Dtor::operator()(vl_); }
Uptr& swap(Uptr& o) noexcept { T* tmp; tmp = vl_; vl_=o.vl_; o.vl_ = tmp; }
Uptr& operator=(Uptr&& o) noexcept { o.swap(*this); }
Uptr& operator=(nullptr_t) noexcept { vl_=nullptr; return *this; }
Uptr(Uptr&& o) noexcept : Uptr(nullptr) { *this = std::move(o); }
Uptr(const Uptr& o) = delete;
Uptr& operator=(const Uptr& o) = delete;
operator T*() noexcept { return vl_; }
operator const T*() const noexcept { return vl_; }
T* release() noexcept { T* ret = vl_; vl_=nullptr; return ret; }
const Dtor& deleter() const noexcept { return *(static_cast<Dtor*>(this)); }
Dtor& deleter() noexcept { return *(static_cast<Dtor*>(this)); }
};
并避免自己定义
get()
和运算符*
,->
和[]
。在这种情况下进行隐式转换有什么问题?
最佳答案
我认为您的问题不是特定于unique_ptr
,而是一般地询问智能指针。
Herb Sutter wrote about this a long time ago。显然,它将允许您编写逻辑错误的代码,例如:
unique_ptr<something> p;
...
delete p; // p is a smart pointer - probably not what you want.
和其他类似的代码。