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30 At the very minimum for
<code class=
"computeroutput"><span class=
"identifier">optional
</span><span class=
"special"><</span><span class=
"identifier">T
</span><span class=
"special">></span></code>
31 to work with a minimum interface it is required that
<code class=
"computeroutput"><span class=
"identifier">T
</span></code>
32 has a publicly accessible no-throw destructor. In that case you need to initialize
33 the optional object with function
<code class=
"computeroutput"><span class=
"identifier">emplace
</span><span class=
"special">()
</span></code> or use
<span class=
"bold"><strong>InPlaceFactories
</strong></span>.
34 Additionally, if
<code class=
"computeroutput"><span class=
"identifier">T
</span></code> is
<code class=
"computeroutput"><span class=
"identifier">Moveable
</span></code>,
<code class=
"computeroutput"><span class=
"identifier">optional
</span><span class=
"special"><</span><span class=
"identifier">T
</span><span class=
"special">></span></code>
35 is also
<code class=
"computeroutput"><span class=
"identifier">Moveable
</span></code> and can be
36 easily initialized from an rvalue of type
<code class=
"computeroutput"><span class=
"identifier">T
</span></code>
37 and be passed by value. Additionally, if
<code class=
"computeroutput"><span class=
"identifier">T
</span></code>
38 is
<code class=
"computeroutput"><span class=
"identifier">Copyable
</span></code>,
<code class=
"computeroutput"><span class=
"identifier">optional
</span><span class=
"special"><</span><span class=
"identifier">T
</span><span class=
"special">></span></code> is
39 also
<code class=
"computeroutput"><span class=
"identifier">Copyable
</span></code> and can be easily
40 initialized from an lvalue of type
<code class=
"computeroutput"><span class=
"identifier">T
</span></code>.
43 <code class=
"computeroutput"><span class=
"identifier">T
</span></code> <span class=
"underline">is
44 not
</span> required to be
<a href=
"http://www.sgi.com/tech/stl/DefaultConstructible.html" target=
"_top">Default
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50 <td align=
"right"><div class=
"copyright-footer">Copyright
© 2003-
2007 Fernando Luis Cacciola Carballal
<br>Copyright
© 2014 Andrzej Krzemie
ński
<p>
51 Distributed under the Boost Software License, Version
1.0. (See accompanying
52 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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