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<link rel="home" href="../../index.html" title="Chapter 1. Boost.Optional">
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<div class="titlepage"><div><div><h3 class="title">
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<a name="optional.introduction.problem"></a><a class="link" href="problem.html" title="Problem">Problem</a>
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</h3></div></div></div>
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<p>
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Suppose we want to read a parameter form a config file which represents some
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integral value, let's call it <code class="computeroutput"><span class="string">"MaxValue"</span></code>.
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It is possible that this parameter is not specified; such situation is no
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error. It is valid to not specify the parameter and in that case the program
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is supposed to behave slightly different. Also suppose that any possible
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value of type <code class="computeroutput"><span class="keyword">int</span></code> is a valid
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value for <code class="computeroutput"><span class="string">"MaxValue"</span></code>,
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so we cannot jut use <code class="computeroutput"><span class="special">-</span><span class="number">1</span></code>
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to represent the absence of the parameter in the config file.
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<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014 Andrzej Krzemieński<p>
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Distributed under the Boost Software License, Version 1.0. (See accompanying
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file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
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