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auto_ptr [C++ Reference]
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<h2><a name="auto_ptr" id="auto_ptr">auto_ptr</a></h2>
<div class="level2">
<p>
Syntax:
</p>
<pre class="c code c++" style="font-family:monospace;"> <span class="co2">#include <memory></span>
auto_ptr<span class="sy0"><</span>class TYPE<span class="sy0">></span> name</pre>
<p>
The auto_ptr class allows the programmer to create pointers that point to other
objects. When auto_ptr pointers are destroyed, the objects to which they point
are also destroyed.
</p>
<p>
The auto_ptr class supports normal pointer operations like =, *, and ->, as
well as two functions TYPE* get() and TYPE* release(). The get() function
returns a pointer to the object that the auto_ptr points to. The release()
function acts similarily to the get() function, but also relieves the auto_ptr
of its memory destruction duties. When an auto_ptr that has been released goes
out of scope, it will not call the destructor of the object that it points to.
</p>
<p>
Warning: It is generally a bad idea to put auto_ptr objects inside C++ STL
containers. C++ containers can do funny things with the data inside them,
including frequent reallocation (when being copied, for instance). Since
calling the destructor of an auto_ptr object will free up the memory associated
with that object, any C++ container reallocation will cause any auto_ptr
objects to become invalid.
</p>
<p>
Example code:
</p>
<pre class="c code c++" style="font-family:monospace;"> <span class="co2">#include <memory></span>
using namespace std<span class="sy0">;</span>
class MyClass <span class="br0">{</span>
public<span class="sy0">:</span>
MyClass<span class="br0">(</span><span class="br0">)</span> <span class="br0">{</span><span class="br0">}</span> <span class="co1">// nothing</span>
~MyClass<span class="br0">(</span><span class="br0">)</span> <span class="br0">{</span><span class="br0">}</span> <span class="co1">// nothing</span>
<span class="kw4">void</span> myFunc<span class="br0">(</span><span class="br0">)</span> <span class="br0">{</span><span class="br0">}</span> <span class="co1">// nothing</span>
<span class="br0">}</span><span class="sy0">;</span>
<span class="kw4">int</span> main<span class="br0">(</span><span class="br0">)</span> <span class="br0">{</span>
auto_ptr<span class="sy0"><</span>MyClass<span class="sy0">></span> ptr1<span class="br0">(</span>new MyClass<span class="br0">)</span><span class="sy0">,</span> ptr2<span class="sy0">;</span>
ptr2 <span class="sy0">=</span> ptr1<span class="sy0">;</span>
ptr2<span class="sy0">-></span>myFunc<span class="br0">(</span><span class="br0">)</span><span class="sy0">;</span>
MyClass<span class="sy0">*</span> ptr <span class="sy0">=</span> ptr2.<span class="me1">get</span><span class="br0">(</span><span class="br0">)</span><span class="sy0">;</span>
ptr<span class="sy0">-></span>myFunc<span class="br0">(</span><span class="br0">)</span><span class="sy0">;</span>
<span class="kw1">return</span> <span class="nu0">0</span><span class="sy0">;</span>
<span class="br0">}</span></pre>
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