1<!doctype HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 2<html> 3<!-- 4(C) Copyright 2002-4 Robert Ramey - http://www.rrsd.com . 5Use, modification and distribution is subject to the Boost Software 6License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at 7http://www.boost.org/LICENSE_1_0.txt) 8--> 9<head> 10<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 11<link rel="stylesheet" type="text/css" href="../../../boost.css"> 12<link rel="stylesheet" type="text/css" href="style.css"> 13<title>Serialization - <code style="white-space: normal">state_saver</code></title> 14</head> 15<body link="#0000ff" vlink="#800080"> 16<table border="0" cellpadding="7" cellspacing="0" width="100%" summary="header"> 17 <tr> 18 <td valign="top" width="300"> 19 <h3><a href="../../../index.htm"><img height="86" width="277" alt="C++ Boost" src="../../../boost.png" border="0"></a></h3> 20 </td> 21 <td valign="top"> 22 <h1 align="center">Serialization</h1> 23 <h2 align="center"><code style="white-space: normal">state_saver</code</h2> 24 </td> 25 </tr> 26</table> 27<hr> 28<p> 29Sometimes a certain value has to change only for a limited scope. 30This class wrapper saves a copy of the current state of some object, 31and resets the object's state at destruction time, undoing any change the object 32may have gone through. Here is the interface: 33 34<pre><code> 35template<class T> 36// T requirements: 37// - POD or object semantic (cannot be reference, function, ...) 38// - copy constructor 39// - operator = (no-throw one preferred) 40class state_saver : private boost::noncopyable 41{ 42private: 43 ... // implementation 44 45public: 46 state_saver(T & object); 47 ~state_saver(); 48}; 49</code></pre> 50 51The complete implementation can be found 52<a target="state_saver" href="../../../boost/serialization/state_saver.hpp">here</a> 53 54The following illustrates how this is expected to be used. 55 56<pre><code> 57#include <boost/state_saver.hpp> 58 59void func(A & a) 60 boost::state_saver<A> s(a); 61 ... // alter state of a by calling non-const functions 62 ... // call other functions 63 // original state of a automatically restored on exit 64} 65</pre></code> 66 67<h3>History</h3> 68This is a generalization of Daryle Walker's 69<a href="../../../libs/io/doc/ios_state.html">io_state_saver</a> library. 70<p> 71Robert Ramey made an initial version for the serialization library. 72<p> 73Pavel Vozenilek made several non-obvious refinements to make it more 74secure and boost friendly 75 76<hr> 77<p><i>© Copyright <a href="http://www.rrsd.com">Robert Ramey</a> 2002-2004. 78Distributed under the Boost Software License, Version 1.0. (See 79accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) 80</i></p> 81</body> 82</html> 83
