39 lines
2.6 KiB
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39 lines
2.6 KiB
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<title>Result returning constructors - Boost.Outcome documentation</title>
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<div class="titlepage"><div><div><h1 style="clear: both">Result returning constructors</h1></div></div></div>
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<p>An oft-asked question during conference talks on Expected/Outcome is how to
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exclusively use <code>result</code> to implement constructor failure. This is asked because
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whilst almost every member function in a class can return a <code>result</code>, constructors
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do not return values and thus cannot return a <code>result</code>. The implication is
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that one cannot avoid throwing C++ exceptions to abort a construction.</p>
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<p>As with most things in C++, one can achieve zero-exception-throw object
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construction using a lot of
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extra typing of boilerplate, and a little bit of simple C++ metaprogramming. This section
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shows you how to implement these for those who are absolutely adverse to ever throwing an exception,
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or cannot because C++ exceptions have been globally disabled.</p>
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<p>The technique described here is not suitable for non-copyable and non-movable
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types. There is also an assumption that moving your type is cheap.</p>
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</div><p><small>Last revised: June 24, 2019 at 21:48:18 +0100</small></p>
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