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25 | <div class="section"> | |
26 | <div class="titlepage"><div><div><h4 class="title"> | |
27 | <a name="boost_multiprecision.tut.misc.debug_adaptor"></a><a class="link" href="debug_adaptor.html" title="debug_adaptor">debug_adaptor</a> | |
28 | </h4></div></div></div> | |
29 | <p> | |
30 | <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> | |
31 | </p> | |
32 | <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> | |
33 | ||
34 | <span class="keyword">template</span> <span class="special"><</span><span class="identifier">Backend</span><span class="special">></span> | |
35 | <span class="keyword">class</span> <span class="identifier">debug_adaptor</span><span class="special">;</span> | |
36 | ||
37 | <span class="special">}}</span> <span class="comment">// namespaces</span> | |
38 | </pre> | |
39 | <p> | |
40 | The <code class="computeroutput"><span class="identifier">debug_adaptor</span></code> type | |
41 | is used in conjunction with <code class="computeroutput"><span class="identifier">number</span></code> | |
42 | and some other backend type: it acts as a thin wrapper around some other | |
43 | backend to class <code class="computeroutput"><span class="identifier">number</span></code> | |
44 | and intercepts all operations on that object storing the result as a string | |
45 | within itself. | |
46 | </p> | |
47 | <p> | |
48 | This type provides <code class="computeroutput"><span class="identifier">numeric_limits</span></code> | |
49 | support whenever the template argument Backend does so. | |
50 | </p> | |
51 | <p> | |
52 | This type is particularly useful when your debugger provides a good view | |
53 | 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 | |
54 | 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>. | |
55 | The down side of this approach is that runtimes are much slower when using | |
56 | this type. Set against that it can make debugging very much easier, certainly | |
57 | much easier than sprinkling code with <code class="computeroutput"><span class="identifier">printf</span></code> | |
58 | statements. | |
59 | </p> | |
60 | <p> | |
61 | When used in conjunction with the Visual C++ debugger visualisers, the | |
62 | value of a multiprecision type that uses this backend is displayed in the | |
63 | debugger just a builtin value would be, here we're inspecting a value of | |
64 | 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> | |
65 | <span class="special">></span></code>: | |
66 | </p> | |
67 | <p> | |
68 | <span class="inlinemediaobject"><img src="../../../../debugger1.png"></span> | |
69 | </p> | |
70 | <p> | |
71 | Otherwise you will need to expand out the view and look at the "debug_value" | |
72 | member: | |
73 | </p> | |
74 | <p> | |
75 | <span class="inlinemediaobject"><img src="../../../../debugger2.png"></span> | |
76 | </p> | |
77 | <p> | |
78 | It works for all the backend types equally too, here it is inspecting a | |
79 | <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> | |
80 | <span class="special">></span></code>: | |
81 | </p> | |
82 | <p> | |
83 | <span class="inlinemediaobject"><img src="../../../../debugger3.png"></span> | |
84 | </p> | |
85 | </div> | |
86 | <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> | |
87 | <td align="left"></td> | |
88 | <td align="right"><div class="copyright-footer">Copyright © 2002-2013 John Maddock and Christopher Kormanyos<p> | |
89 | Distributed under the Boost Software License, Version 1.0. (See accompanying | |
90 | 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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