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| <div class="titlepage"><div><div><h4 class="title"> |
| <a name="boost_multiprecision.tut.misc.debug_adaptor"></a><a class="link" href="debug_adaptor.html" title="debug_adaptor">debug_adaptor</a> |
| </h4></div></div></div> |
| <p> |
| <code class="computeroutput"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">multiprecision</span><span class="special">/</span><span class="identifier">debug_adaptor</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span></code> |
| </p> |
| <pre class="programlisting"><span class="keyword">namespace</span> <span class="identifier">boost</span><span class="special">{</span> <span class="keyword">namespace</span> <span class="identifier">multiprecision</span><span class="special">{</span> |
| |
| <span class="keyword">template</span> <span class="special"><</span><span class="identifier">Backend</span><span class="special">></span> |
| <span class="keyword">class</span> <span class="identifier">debug_adaptor</span><span class="special">;</span> |
| |
| <span class="special">}}</span> <span class="comment">// namespaces</span> |
| </pre> |
| <p> |
| The <code class="computeroutput"><span class="identifier">debug_adaptor</span></code> type |
| is used in conjunction with <code class="computeroutput"><span class="identifier">number</span></code> |
| and some other backend type: it acts as a thin wrapper around some other |
| backend to class <code class="computeroutput"><span class="identifier">number</span></code> |
| and intercepts all operations on that object storing the result as a string |
| within itself. |
| </p> |
| <p> |
| This type provides <code class="computeroutput"><span class="identifier">numeric_limits</span></code> |
| support whenever the template argument Backend does so. |
| </p> |
| <p> |
| This type is particularly useful when your debugger provides a good view |
| of <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span></code>: when this is the case multiprecision |
| values can easily be inspected in the debugger by looking at the <code class="computeroutput"><span class="identifier">debug_value</span></code> member of <code class="computeroutput"><span class="identifier">debug_adaptor</span></code>. |
| The down side of this approach is that runtimes are much slower when using |
| this type. Set against that it can make debugging very much easier, certainly |
| much easier than sprinkling code with <code class="computeroutput"><span class="identifier">printf</span></code> |
| statements. |
| </p> |
| <p> |
| When used in conjunction with the Visual C++ debugger visualisers, the |
| value of a multiprecision type that uses this backend is displayed in the |
| debugger just a builtin value would be, here we're inspecting a value of |
| type <code class="computeroutput"><span class="identifier">number</span><span class="special"><</span><span class="identifier">debug_adaptor</span><span class="special"><</span><span class="identifier">cpp_dec_float</span><span class="special"><</span><span class="number">50</span><span class="special">></span> <span class="special">></span> |
| <span class="special">></span></code>: |
| </p> |
| <p> |
| <span class="inlinemediaobject"><img src="../../../../debugger1.png"></span> |
| </p> |
| <p> |
| Otherwise you will need to expand out the view and look at the "debug_value" |
| member: |
| </p> |
| <p> |
| <span class="inlinemediaobject"><img src="../../../../debugger2.png"></span> |
| </p> |
| <p> |
| It works for all the backend types equally too, here it is inspecting a |
| <code class="computeroutput"><span class="identifier">number</span><span class="special"><</span><span class="identifier">debug_adaptor</span><span class="special"><</span><span class="identifier">gmp_rational</span><span class="special">></span> |
| <span class="special">></span></code>: |
| </p> |
| <p> |
| <span class="inlinemediaobject"><img src="../../../../debugger3.png"></span> |
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| <td align="right"><div class="copyright-footer">Copyright © 2002-2013 John Maddock and Christopher Kormanyos<p> |
| Distributed under the Boost Software License, Version 1.0. (See accompanying |
| 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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