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<title>Serialization - <code style="white-space: normal">state_saver</code></title>
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      <h3><a href="../../../index.htm"><img height="86" width="277" alt="C++ Boost" src="../../../boost.png" border="0"></a></h3>
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      <h1 align="center">Serialization</h1>
      <h2 align="center"><code style="white-space: normal">state_saver</code</h2>
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<p>
Sometimes a certain value has to change only for a limited scope. 
This class wrapper saves a copy of the current state of some object, 
and resets the object's state at destruction time, undoing any change the object 
may have gone through.  Here is the interface:

<pre><code>
template<class T>
// T requirements:
//  - POD or object semantic (cannot be reference, function, ...)
//  - copy constructor
//  - operator = (no-throw one preferred)
class state_saver : private boost::noncopyable
{
private:
    ... // implementation

public:
    state_saver(T & object);
    ~state_saver();
};
</code></pre>

The complete implementation can be found
<a target="state_saver" href="../../../boost/serialization/state_saver.hpp">here</a>

The following illustrates how this is expected to be used.

<pre><code>
#include &lt;boost/state_saver.hpp&gt;

void func(A & a)
    boost::state_saver&lt;A&gt; s(a);
    ... // alter state of a by calling non-const functions
    ... // call other functions
    // original state of a automatically restored on exit
}
</pre></code>

<h3>History</h3>
This is a generalization of Daryle Walker's 
<a href="../../../libs/io/doc/ios_state.html">io_state_saver</a> library.
<p>
Robert Ramey made an initial version for the serialization library.
<p>
Pavel Vozenilek made several non-obvious refinements to make it more
secure and boost friendly

<hr>
<p><i>&copy; Copyright <a href="http://www.rrsd.com">Robert Ramey</a> 2002-2004. 
Distributed under the Boost Software License, Version 1.0. (See
accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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