Item 30. Smart Pointer Members, Part 1: A Problem with auto_ptr

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Item 30. Smart Pointer Members , Part 1: A Problem with auto_ptr

Difficulty: 5

Most C++ programmers know they have to take special care for classes with pointer members. But what about classes with auto_ptr members? And can we make life safer for ourselves and our users by devising a smart pointer class designed specifically for class membership?

1. Consider the following class:

    // Example 30-1 // class X1 {   // ... private:   Y* y_; }; 

   If an X1 object owns its pointed-at Y object, why can't the author of X1 use the compiler-generated destructor, copy constructor, and copy assignment?

2. What are the advantages and drawbacks of the following approach?

    // Example 30-2 // class X2 {   // ... private:   auto_ptr<Y> y_; }; 

I l @ ve RuBoard