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    <p>A smart pointer is like a regular (typed) pointer, like "char*", except when the pointer itself goes out of scope then what it points to is deleted as well. You can use it like you would a regular pointer, by using "->", but not if you need an actual pointer to the data. For that, you can use "&amp;*ptr".</p> <p>It is useful for:</p> <ul> <li><p>Objects that must be allocated with new, but that you'd like to have the same lifetime as something on that stack. If the object is assigned to a smart pointer, then they will be deleted when the program exits that function/block.</p></li> <li><p>Data members of classes, so that when the object is deleted all the owned data is deleted as well, without any special code in the destructor (you will need to be sure the destructor is virtual, which is almost always a good thing to do).</p></li> </ul> <p>You may <em>not</em> want to use a smart pointer when:</p> <ul> <li>... the pointer shouldn't actually own the data... i.e., when you are just using the data, but you want it to survive the function where you are referencing it.</li> <li>... the smart pointer isn't itself going to be destroyed at some point. You don't want it to sit in memory that never gets destroyed (such as in an object that is dynamically allocated but won't be explicitly deleted).</li> <li>... two smart pointers might point to the same data. (There are, however, even smarter pointers that will handle that... that is called <a href="http://en.wikipedia.org/wiki/Reference_counting" rel="noreferrer">reference counting</a>.)</li> </ul> <p>See also:</p> <ul> <li><a href="http://en.wikipedia.org/wiki/Garbage_collection_(computer_science)" rel="noreferrer">garbage collection</a>.</li> <li><a href="https://stackoverflow.com/questions/94227/smart-pointers-or-who-owns-you-baby">This stack overflow question</a> regarding data ownership</li> </ul>
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