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53 lines
2.6 KiB
HTML
53 lines
2.6 KiB
HTML
<html>
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<meta http-equiv="Content-Language" content="en-us">
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<meta http-equiv="Content-Type" content="text/html; charset=windows-1252">
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<meta name="GENERATOR" content="Microsoft FrontPage 4.0">
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<meta name="ProgId" content="FrontPage.Editor.Document">
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<title>Use other Boost or C</title>
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</head>
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<body>
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<ul>
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<li>Use other Boost or C++ Standard Library components only when the benefits
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outweigh the costs.</li>
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</ul>
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<p>(Details)</p>
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<p>The benefits of using components from other libraries include clearer, more
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understandable, code, reduced development and maintenance costs, and the
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assurance which comes from using well-known and trusted building blocks.</p>
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<p>The costs incurred may include added compilation and runtime costs, and
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undesirable coupling between components. If the interface to the
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additional component is complex, using it may make code less readable, and thus
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actually increase development and maintenance costs.</p>
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<p><b>Example where another boost component should be used:</b>
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boost::noncopyable (in boost/utility.hpp) has considerable benefits; it
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simplifies code, improves readability, and signals intent. Costs are low
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as coupling is limited; it uses no other classes and includes only the
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generally lightweight headers <boost/config.hpp> and <cstddef>.
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There are no runtime costs at all. With costs so low and benefits so high, other
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boost libraries should use boost::noncopyable except in exceptional
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circumstances.</p>
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<p><b>Example where a standard library component might be used:</b> Providing
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diagnostic output as a debugging aid can be a nice feature for a library. Yet
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using Standard Library iostreams for the purpose involves a lot of additional
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coupling, if iostreams is otherwise unused, and may be a complete waste if the
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library is used in a GUI or embedded application. It might be better to
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redesign the boost library so that the user supplies the output mechanism,
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avoiding marginal use of iostreams.</p>
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<p><b>Example where another boost component should not be used:</b> The
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boost dir_it library has considerable coupling and runtime costs, not to mention
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portability issues with unsupported operating systems. While completely
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appropriate when directory iteration is required, it would not be reasonable for
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another boost library to use dir_it just to check that a file is available
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before opening, since Standard Library file open functionality does this at
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lower cost. Don't use dir_it just for the sake of using a boost library.</p>
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<p> </p>
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<p> </p>
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</body>
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</html>
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