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copied!<p>Yes, it can leak.</p> <p>If <code>new std::shared_ptr</code> throws, there is nothing to clean up the memory allocated by <code>new int</code>.</p> <p>In general, automatic <code>delete</code> invocations are made only when a constructor throws after a corresponding <code>new</code>.</p> <p>To elaborate, you can rewrite the code as follows:</p> <pre><code>// if 'new' throws, we just get a bad_alloc, nothing leaked int *iptr = new int; // if 'new' throws, nothing will clean up iptr // // if, for whatever reason, ctor of std::shared_ptr<int> throws, // its memory gets reclaimed by an implicit delete, but iptr's target // is still lost. auto *ptrptr = new std::shared_ptr<int>(iptr); // EDIT: If the constructor of shared_ptr fails, it will delete // the memory it is given, though this still doesn't eliminate the // leak that can occur if the above `new` fails. </code></pre> <p>EDIT:</p> <p>The example above, and this explanation, were really meant to indicate that there isn't anything special about <code>std::shared_ptr</code> as compared to any other smart pointer implementation, or some type that accepts a pointer as a constructor argument for that matter.</p> <p>In the latter case, it really depends on what the type's constructor does with its argument. In the case of <code>std::shared_ptr</code>, it most likely will not throw an exception unless it fails to allocate a control block (if that is, in fact, how it is implemented).</p> <p>If the constructor of <code>std::shared_ptr</code> does fail, at least with the implementation I am using (VS2012), it actually <em>does</em> delete the memory it is given.</p>

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