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    <p>C++98 does not provide any smart pointers except <code>auto_ptr</code> which is fraught with its own issues. C++0X tries to fix this by bringing in a few more varieties (<code>shared_ptr</code>, <code>unique_ptr</code> etc.). In the meantime the best bet is to use Boost. Take a look at the various flavors available to you <a href="http://www.boost.org/doc/libs/1_43_0/libs/smart_ptr/smart_ptr.htm" rel="noreferrer">here</a>. Boost is community driven, extensively tested and of course free. There is excellent documentation with sample code that will help you get started.</p> <blockquote> <p>Can you explain what are the types of smart pointers, how do they work and when to use them?</p> </blockquote> <p>There are a number of them. In short:</p> <blockquote> <p><strong><code>scoped_ptr</code></strong> <code>&lt;boost/scoped_ptr.hpp&gt;</code> Simple sole ownership of single objects. Noncopyable.</p> <p><strong><code>scoped_array</code></strong> <code>&lt;boost/scoped_array.hpp&gt;</code> Simple sole ownership of arrays. Noncopyable.</p> <p><strong><code>shared_ptr</code></strong> <code>&lt;boost/shared_ptr.hpp&gt;</code> Object ownership shared among multiple pointers. </p> <p><strong><code>shared_array</code></strong> <code>&lt;boost/shared_array.hpp&gt;</code> Array ownership shared among multiple pointers. </p> <p><strong><code>weak_ptr</code></strong> <code>&lt;boost/weak_ptr.hpp&gt;</code> Non-owning observers of an object owned by shared_ptr. </p> <p><strong><code>intrusive_ptr</code></strong> <code>&lt;boost/intrusive_ptr.hpp&gt;</code> Shared ownership of objects with an embedded reference count.</p> </blockquote> <p>(That is from Boost documentation and note that they have containers for such pointers too!)</p> <blockquote> <p>Also, what is the "protocol" when receiving or passing raw pointers in interfaces written by other people?</p> </blockquote> <p>For me the most important rules are:</p> <ul> <li>Const-qualification</li> <li>Not to deallocate stuff I did not allocate</li> <li>Check for transfer of ownership/move semantics </li> </ul>
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    1. POHow to use C++ Smart Pointers?
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    1. COGood summation. I disagree that auto_ptr is fraught with issues. If yuo don't understand what it does then it can take you by surprise but that is solved by reading the documentation. Also the new C++0x provides std::unique_ptr which is practically a drop in replacement for auto_ptr but makes the move semantics more obvious to newcomers. It would also be nice to see which ones have been included into the new standard lib.
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    2. COGranted. I have been a bit harsh and we'll continue to live with `auto_ptr` (though my copy of the draft i.e. n3090 says it is deprecated).
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    3. COCalling boost documentation "excellent" is a bit of a stretch :). The quality goes up and down, depending on the lib in question. But good answer in general, +1.
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