ceph/src/boost/libs/optional/doc/html/boost_optional/reference/header__boost_optional_optional_hpp_/detailed_semantics___optional_references.html

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  27 <a name="boost_optional.reference.header__boost_optional_optional_hpp_.detailed_semantics___optional_references"></a><a class="link" href="detailed_semantics___optional_references.html" title="Detailed Semantics - Optional References">Detailed
  28         Semantics - Optional References</a>
  29 </h4></div></div></div>
  30 <p>
  31           <span class="inlinemediaobject"><img src="../../../images/space.png" alt="space"></span>
  32         </p>
  33 <a name="reference_optional_ref_default_ctor"></a><div class="blockquote"><blockquote class="blockquote"><p>
  34             <code class="computeroutput"><span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&amp;&gt;::</span><span class="identifier">optional</span><span class="special">()</span>
  35             <span class="keyword">noexcept</span><span class="special">;</span></code>
  36           </p></blockquote></div>
  37 <div class="blockquote"><blockquote class="blockquote"><p>
  38             <code class="computeroutput"><span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&amp;&gt;::</span><span class="identifier">optional</span><span class="special">(</span><span class="identifier">none_t</span><span class="special">)</span> <span class="keyword">noexcept</span><span class="special">;</span></code>
  39           </p></blockquote></div>
  40 <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem">
  41               <span class="bold"><strong>Postconditions:</strong></span> <code class="computeroutput"><span class="keyword">bool</span><span class="special">(*</span><span class="keyword">this</span><span class="special">)</span> <span class="special">==</span> <span class="keyword">false</span></code>; <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> refers to nothing.
  42             </li></ul></div>
  43 <p>
  44           <span class="inlinemediaobject"><img src="../../../images/space.png" alt="space"></span>
  45         </p>
  46 <a name="reference_optional_ref_value_ctor"></a><div class="blockquote"><blockquote class="blockquote"><p>
  47             <code class="computeroutput"><span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">R</span><span class="special">&gt;</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&amp;&gt;::</span><span class="identifier">optional</span><span class="special">(</span><span class="identifier">R</span><span class="special">&amp;&amp;</span> <span class="identifier">r</span><span class="special">)</span> <span class="keyword">noexcept</span><span class="special">;</span></code>
  48           </p></blockquote></div>
  49 <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
  50 <li class="listitem">
  51               <span class="bold"><strong>Postconditions:</strong></span> <code class="computeroutput"><span class="keyword">bool</span><span class="special">(*</span><span class="keyword">this</span><span class="special">)</span> <span class="special">==</span> <span class="keyword">true</span></code>; <code class="computeroutput"><span class="identifier">addressof</span><span class="special">(**</span><span class="keyword">this</span><span class="special">)</span> <span class="special">==</span> <span class="identifier">addressof</span><span class="special">(</span><span class="identifier">r</span><span class="special">)</span></code>.
  52             </li>
  53 <li class="listitem">
  54               <span class="bold"><strong>Remarks:</strong></span> Unless <code class="computeroutput"><span class="identifier">R</span></code>
  55               is an lvalue reference, the program is ill-formed. This constructor
  56               does not participate in overload resolution if <code class="computeroutput"><span class="identifier">decay</span><span class="special">&lt;</span><span class="identifier">R</span><span class="special">&gt;</span></code> is an instance of <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">optional</span></code>.
  57             </li>
  58 <li class="listitem">
  59               <span class="bold"><strong>Notes:</strong></span> This constructor is declared
  60               <code class="computeroutput"><span class="keyword">explicit</span></code> on compilers
  61               that do not correctly suport binding to const lvalues of integral types.
  62               For more details <a class="link" href="../../dependencies_and_portability/optional_reference_binding.html#optional_reference_binding">see here</a>.
  63             </li>
  64 <li class="listitem">
  65               <span class="bold"><strong>Example:</strong></span>
  66 <pre class="programlisting"><span class="identifier">T</span> <span class="identifier">v</span><span class="special">;</span>
  67 <span class="identifier">T</span><span class="special">&amp;</span> <span class="identifier">vref</span> <span class="special">=</span> <span class="identifier">v</span> <span class="special">;</span>
  68 <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&amp;&gt;</span> <span class="identifier">opt</span><span class="special">(</span><span class="identifier">vref</span><span class="special">);</span>
  69 <span class="identifier">assert</span> <span class="special">(</span> <span class="special">*</span><span class="identifier">opt</span> <span class="special">==</span> <span class="identifier">v</span> <span class="special">)</span> <span class="special">;</span>
  70 <span class="special">++</span> <span class="identifier">v</span> <span class="special">;</span> <span class="comment">// mutate referee</span>
  71 <span class="identifier">assert</span> <span class="special">(*</span><span class="identifier">opt</span> <span class="special">==</span> <span class="identifier">v</span><span class="special">);</span>
  72 </pre>
  73             </li>
  74 </ul></div>
  75 <p>
  76           <span class="inlinemediaobject"><img src="../../../images/space.png" alt="space"></span>
  77         </p>
  78 <a name="reference_optional_ref_cond_value_ctor"></a><div class="blockquote"><blockquote class="blockquote"><p>
  79             <code class="computeroutput"><span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">R</span><span class="special">&gt;</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&amp;&gt;::</span><span class="identifier">optional</span><span class="special">(</span><span class="keyword">bool</span> <span class="identifier">cond</span><span class="special">,</span> <span class="identifier">R</span><span class="special">&amp;&amp;</span>
  80             <span class="identifier">r</span><span class="special">)</span>
  81             <span class="keyword">noexcept</span><span class="special">;</span></code>
  82           </p></blockquote></div>
  83 <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
  84 <li class="listitem">
  85               <span class="bold"><strong>Effects: </strong></span> Initializes <code class="computeroutput"><span class="identifier">ref</span></code> with expression <code class="computeroutput"><span class="identifier">cond</span> <span class="special">?</span>
  86               <span class="identifier">addressof</span><span class="special">(</span><span class="identifier">r</span><span class="special">)</span> <span class="special">:</span> <span class="keyword">nullptr</span></code>.
  87             </li>
  88 <li class="listitem">
  89               <span class="bold"><strong>Postconditions:</strong></span> <code class="computeroutput"><span class="keyword">bool</span><span class="special">(*</span><span class="keyword">this</span><span class="special">)</span> <span class="special">==</span> <span class="identifier">cond</span></code>; If <code class="computeroutput"><span class="keyword">bool</span><span class="special">(*</span><span class="keyword">this</span><span class="special">)</span></code>, <code class="computeroutput"><span class="identifier">addressof</span><span class="special">(**</span><span class="keyword">this</span><span class="special">)</span> <span class="special">==</span> <span class="identifier">addressof</span><span class="special">(</span><span class="identifier">r</span><span class="special">)</span></code>.
  90             </li>
  91 <li class="listitem">
  92               <span class="bold"><strong>Remarks:</strong></span> Unless <code class="computeroutput"><span class="identifier">R</span></code>
  93               is an lvalue reference, the program is ill-formed. This constructor
  94               does not participate in overload resolution if <code class="computeroutput"><span class="identifier">decay</span><span class="special">&lt;</span><span class="identifier">R</span><span class="special">&gt;</span></code> is an instance of <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">optional</span></code>.
  95             </li>
  96 </ul></div>
  97 <p>
  98           <span class="inlinemediaobject"><img src="../../../images/space.png" alt="space"></span>
  99         </p>
 100 <a name="reference_optional_ref_copy_ctor"></a><div class="blockquote"><blockquote class="blockquote"><p>
 101             <code class="computeroutput"><span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&amp;&gt;::</span><span class="identifier">optional</span> <span class="special">(</span>
 102             <span class="identifier">optional</span> <span class="keyword">const</span><span class="special">&amp;</span> <span class="identifier">rhs</span>
 103             <span class="special">)</span> <span class="keyword">noexcept</span>
 104             <span class="special">;</span></code>
 105           </p></blockquote></div>
 106 <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
 107 <li class="listitem">
 108               <span class="bold"><strong>Effects: </strong></span> Initializes <code class="computeroutput"><span class="identifier">ref</span></code> with expression <code class="computeroutput"><span class="identifier">rhs</span><span class="special">.</span><span class="identifier">ref</span></code>.
 109             </li>
 110 <li class="listitem">
 111               <span class="bold"><strong>Postconditions:</strong></span> <code class="computeroutput"><span class="keyword">bool</span><span class="special">(*</span><span class="keyword">this</span><span class="special">)</span> <span class="special">==</span> <span class="keyword">bool</span><span class="special">(</span><span class="identifier">rhs</span><span class="special">)</span></code>.
 112             </li>
 113 <li class="listitem">
 114               <span class="bold"><strong>Example:</strong></span>
 115 <pre class="programlisting"><span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&amp;&gt;</span> <span class="identifier">uninit</span> <span class="special">;</span>
 116 <span class="identifier">assert</span> <span class="special">(!</span><span class="identifier">uninit</span><span class="special">);</span>
 117
 118 <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&amp;&gt;</span> <span class="identifier">uinit2</span> <span class="special">(</span> <span class="identifier">uninit</span> <span class="special">)</span> <span class="special">;</span>
 119 <span class="identifier">assert</span> <span class="special">(</span> <span class="identifier">uninit2</span> <span class="special">==</span> <span class="identifier">uninit</span> <span class="special">);</span>
 120
 121 <span class="identifier">T</span> <span class="identifier">v</span> <span class="special">=</span> <span class="number">2</span> <span class="special">;</span> <span class="identifier">T</span><span class="special">&amp;</span> <span class="identifier">ref</span> <span class="special">=</span> <span class="identifier">v</span> <span class="special">;</span>
 122 <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span> <span class="identifier">init</span><span class="special">(</span><span class="identifier">ref</span><span class="special">);</span>
 123 <span class="identifier">assert</span> <span class="special">(</span> <span class="special">*</span><span class="identifier">init</span> <span class="special">==</span> <span class="identifier">v</span> <span class="special">)</span> <span class="special">;</span>
 124
 125 <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span> <span class="identifier">init2</span> <span class="special">(</span> <span class="identifier">init</span> <span class="special">)</span> <span class="special">;</span>
 126 <span class="identifier">assert</span> <span class="special">(</span> <span class="special">*</span><span class="identifier">init2</span> <span class="special">==</span> <span class="identifier">v</span> <span class="special">)</span> <span class="special">;</span>
 127
 128 <span class="identifier">v</span> <span class="special">=</span> <span class="number">3</span> <span class="special">;</span>
 129
 130 <span class="identifier">assert</span> <span class="special">(</span> <span class="special">*</span><span class="identifier">init</span>  <span class="special">==</span> <span class="number">3</span> <span class="special">)</span> <span class="special">;</span>
 131 <span class="identifier">assert</span> <span class="special">(</span> <span class="special">*</span><span class="identifier">init2</span> <span class="special">==</span> <span class="number">3</span> <span class="special">)</span> <span class="special">;</span>
 132 </pre>
 133             </li>
 134 </ul></div>
 135 <p>
 136           <span class="inlinemediaobject"><img src="../../../images/space.png" alt="space"></span>
 137         </p>
 138 <a name="reference_optional_ref_ctor_from_opt_U"></a><div class="blockquote"><blockquote class="blockquote"><p>
 139             <code class="computeroutput"><span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">U</span><span class="special">&gt;</span> <span class="keyword">explicit</span>
 140             <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&amp;&gt;::</span><span class="identifier">optional</span> <span class="special">(</span>
 141             <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">U</span><span class="special">&amp;&gt;</span>
 142             <span class="keyword">const</span><span class="special">&amp;</span>
 143             <span class="identifier">rhs</span> <span class="special">)</span>
 144             <span class="keyword">noexcept</span> <span class="special">;</span></code>
 145           </p></blockquote></div>
 146 <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
 147 <li class="listitem">
 148               <span class="bold"><strong>Requires:</strong></span> <code class="computeroutput"><span class="identifier">is_convertible</span><span class="special">&lt;</span><span class="identifier">U</span><span class="special">&amp;,</span> <span class="identifier">T</span><span class="special">&amp;&gt;::</span><span class="identifier">value</span></code>
 149               is <code class="computeroutput"><span class="keyword">true</span></code>.
 150             </li>
 151 <li class="listitem">
 152               <span class="bold"><strong>Effects: </strong></span> Initializes <code class="computeroutput"><span class="identifier">ref</span></code> with expression <code class="computeroutput"><span class="identifier">rhs</span><span class="special">.</span><span class="identifier">ref</span></code>.
 153             </li>
 154 <li class="listitem">
 155               <span class="bold"><strong>Postconditions:</strong></span> <code class="computeroutput"><span class="keyword">bool</span><span class="special">(*</span><span class="keyword">this</span><span class="special">)</span> <span class="special">==</span> <span class="keyword">bool</span><span class="special">(</span><span class="identifier">rhs</span><span class="special">)</span></code>.
 156             </li>
 157 </ul></div>
 158 <p>
 159           <span class="inlinemediaobject"><img src="../../../images/space.png" alt="space"></span>
 160         </p>
 161 <a name="reference_optional_ref_assign_none_t"></a><div class="blockquote"><blockquote class="blockquote"><p>
 162             <code class="computeroutput"><span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&amp;&gt;::</span><span class="keyword">operator</span><span class="special">=</span> <span class="special">(</span> <span class="identifier">none_t</span>
 163             <span class="special">)</span> <span class="keyword">noexcept</span>
 164             <span class="special">;</span></code>
 165           </p></blockquote></div>
 166 <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
 167 <li class="listitem">
 168               <span class="bold"><strong>Effects: </strong></span> Assigns <code class="computeroutput"><span class="identifier">ref</span></code>
 169               with expression <code class="computeroutput"><span class="keyword">nullptr</span></code>.
 170             </li>
 171 <li class="listitem">
 172               <span class="bold"><strong>returns:</strong></span> <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>.
 173             </li>
 174 <li class="listitem">
 175               <span class="bold"><strong>Postconditions:</strong></span> <code class="computeroutput"><span class="keyword">bool</span><span class="special">(*</span><span class="keyword">this</span><span class="special">)</span> <span class="special">==</span> <span class="keyword">false</span></code>.
 176             </li>
 177 </ul></div>
 178 <a name="reference_optional_ref_copy_assign"></a><div class="blockquote"><blockquote class="blockquote"><p>
 179             <code class="computeroutput"><span class="identifier">optional</span><span class="special">&amp;</span>
 180             <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&amp;&gt;::</span><span class="keyword">operator</span><span class="special">=</span> <span class="special">(</span> <span class="identifier">optional</span>
 181             <span class="keyword">const</span><span class="special">&amp;</span>
 182             <span class="identifier">rhs</span> <span class="special">)</span>
 183             <span class="keyword">noexcept</span> <span class="special">;</span></code>
 184           </p></blockquote></div>
 185 <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
 186 <li class="listitem">
 187               <span class="bold"><strong>Effects: </strong></span> Assigns <code class="computeroutput"><span class="identifier">ref</span></code>
 188               with expression <code class="computeroutput"><span class="identifier">rhs</span><span class="special">.</span><span class="identifier">ref</span></code>.
 189             </li>
 190 <li class="listitem">
 191               <span class="bold"><strong>returns:</strong></span> <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>.
 192             </li>
 193 <li class="listitem">
 194               <span class="bold"><strong>Postconditions:</strong></span> <code class="computeroutput"><span class="keyword">bool</span><span class="special">(*</span><span class="keyword">this</span><span class="special">)</span> <span class="special">==</span> <span class="keyword">bool</span><span class="special">(</span><span class="identifier">rhs</span><span class="special">)</span></code>.
 195             </li>
 196 <li class="listitem">
 197               <span class="bold"><strong>Notes:</strong></span> This behaviour is called <span class="emphasis"><em>rebinding
 198               semantics</em></span>. See <a class="link" href="../../tutorial/optional_references/rebinding_semantics_for_assignment_of_optional_references.html" title="Rebinding semantics for assignment of optional references">here</a>
 199               for details.
 200             </li>
 201 <li class="listitem">
 202               <span class="bold"><strong>Example:</strong></span>
 203 <pre class="programlisting"><span class="keyword">int</span> <span class="identifier">a</span> <span class="special">=</span> <span class="number">1</span> <span class="special">;</span>
 204 <span class="keyword">int</span> <span class="identifier">b</span> <span class="special">=</span> <span class="number">2</span> <span class="special">;</span>
 205 <span class="identifier">T</span><span class="special">&amp;</span> <span class="identifier">ra</span> <span class="special">=</span> <span class="identifier">a</span> <span class="special">;</span>
 206 <span class="identifier">T</span><span class="special">&amp;</span> <span class="identifier">rb</span> <span class="special">=</span> <span class="identifier">b</span> <span class="special">;</span>
 207 <span class="identifier">optional</span><span class="special">&lt;</span><span class="keyword">int</span><span class="special">&amp;&gt;</span> <span class="identifier">def</span> <span class="special">;</span>
 208 <span class="identifier">optional</span><span class="special">&lt;</span><span class="keyword">int</span><span class="special">&amp;&gt;</span> <span class="identifier">ora</span><span class="special">(</span><span class="identifier">ra</span><span class="special">)</span> <span class="special">;</span>
 209 <span class="identifier">optional</span><span class="special">&lt;</span><span class="keyword">int</span><span class="special">&amp;&gt;</span> <span class="identifier">orb</span><span class="special">(</span><span class="identifier">rb</span><span class="special">)</span> <span class="special">;</span>
 210
 211 <span class="identifier">def</span> <span class="special">=</span> <span class="identifier">orb</span> <span class="special">;</span> <span class="comment">// binds 'def' to 'b' through 'rb' wrapped within 'orb'</span>
 212 <span class="identifier">assert</span> <span class="special">(</span> <span class="special">*</span><span class="identifier">def</span> <span class="special">==</span> <span class="identifier">b</span> <span class="special">)</span> <span class="special">;</span>
 213 <span class="special">*</span><span class="identifier">def</span> <span class="special">=</span> <span class="identifier">ora</span> <span class="special">;</span> <span class="comment">// changes the value of 'b' to a copy of the value of 'a'</span>
 214 <span class="identifier">assert</span> <span class="special">(</span> <span class="identifier">b</span> <span class="special">==</span> <span class="identifier">a</span> <span class="special">)</span> <span class="special">;</span>
 215 <span class="keyword">int</span> <span class="identifier">c</span> <span class="special">=</span> <span class="number">3</span><span class="special">;</span>
 216 <span class="keyword">int</span><span class="special">&amp;</span> <span class="identifier">rc</span> <span class="special">=</span> <span class="identifier">c</span> <span class="special">;</span>
 217 <span class="identifier">optional</span><span class="special">&lt;</span><span class="keyword">int</span><span class="special">&amp;&gt;</span> <span class="identifier">orc</span><span class="special">(</span><span class="identifier">rc</span><span class="special">)</span> <span class="special">;</span>
 218 <span class="identifier">ora</span> <span class="special">=</span> <span class="identifier">orc</span> <span class="special">;</span> <span class="comment">// REBINDS ora to 'c' through 'rc'</span>
 219 <span class="identifier">c</span> <span class="special">=</span> <span class="number">4</span> <span class="special">;</span>
 220 <span class="identifier">assert</span> <span class="special">(</span> <span class="special">*</span><span class="identifier">ora</span> <span class="special">==</span> <span class="number">4</span> <span class="special">)</span> <span class="special">;</span>
 221 </pre>
 222             </li>
 223 </ul></div>
 224 <a name="reference_optional_ref_assign_optional_U"></a><div class="blockquote"><blockquote class="blockquote"><p>
 225             <code class="computeroutput"><span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">U</span><span class="special">&gt;</span> <span class="identifier">optional</span><span class="special">&amp;</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&amp;&gt;::</span><span class="keyword">operator</span><span class="special">=</span> <span class="special">(</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">U</span><span class="special">&amp;&gt;</span> <span class="keyword">const</span><span class="special">&amp;</span> <span class="identifier">rhs</span>
 226             <span class="special">)</span> <span class="keyword">noexcept</span>
 227             <span class="special">;</span></code>
 228           </p></blockquote></div>
 229 <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
 230 <li class="listitem">
 231               <span class="bold"><strong>Requires:</strong></span> <code class="computeroutput"><span class="identifier">is_convertible</span><span class="special">&lt;</span><span class="identifier">U</span><span class="special">&amp;,</span> <span class="identifier">T</span><span class="special">&amp;&gt;::</span><span class="identifier">value</span></code>
 232               is <code class="computeroutput"><span class="keyword">true</span></code>.
 233             </li>
 234 <li class="listitem">
 235               <span class="bold"><strong>Effects: </strong></span> Assigns <code class="computeroutput"><span class="identifier">ref</span></code>
 236               with expression <code class="computeroutput"><span class="identifier">rhs</span><span class="special">.</span><span class="identifier">ref</span></code>.
 237             </li>
 238 <li class="listitem">
 239               <span class="bold"><strong>returns:</strong></span> <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>.
 240             </li>
 241 <li class="listitem">
 242               <span class="bold"><strong>Postconditions:</strong></span> <code class="computeroutput"><span class="keyword">bool</span><span class="special">(*</span><span class="keyword">this</span><span class="special">)</span> <span class="special">==</span> <span class="keyword">bool</span><span class="special">(</span><span class="identifier">rhs</span><span class="special">)</span></code>.
 243             </li>
 244 </ul></div>
 245 <p>
 246           <span class="inlinemediaobject"><img src="../../../images/space.png" alt="space"></span>
 247         </p>
 248 <a name="reference_optional_ref_assign_R"></a><div class="blockquote"><blockquote class="blockquote"><p>
 249             <code class="computeroutput"><span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">R</span><span class="special">&gt;</span> <span class="identifier">optional</span><span class="special">&amp;</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&amp;&gt;::</span><span class="keyword">operator</span><span class="special">=</span> <span class="special">(</span> <span class="identifier">R</span><span class="special">&amp;&amp;</span> <span class="identifier">r</span>
 250             <span class="special">)</span> <span class="keyword">noexcept</span>
 251             <span class="special">;</span></code>
 252           </p></blockquote></div>
 253 <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
 254 <li class="listitem">
 255               <span class="bold"><strong>Effects: </strong></span> Assigns <code class="computeroutput"><span class="identifier">ref</span></code>
 256               with expression <code class="computeroutput"><span class="identifier">r</span></code>.
 257             </li>
 258 <li class="listitem">
 259               <span class="bold"><strong>returns:</strong></span> <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>.
 260             </li>
 261 <li class="listitem">
 262               <span class="bold"><strong>Postconditions:</strong></span> <code class="computeroutput"><span class="keyword">bool</span><span class="special">(*</span><span class="keyword">this</span><span class="special">)</span> <span class="special">==</span> <span class="keyword">true</span></code>.
 263             </li>
 264 <li class="listitem">
 265               <span class="bold"><strong>Remarks:</strong></span> Unless <code class="computeroutput"><span class="identifier">R</span></code>
 266               is an lvalue reference, the program is ill-formed. This function does
 267               not participate in overload resolution if <code class="computeroutput"><span class="identifier">decay</span><span class="special">&lt;</span><span class="identifier">R</span><span class="special">&gt;</span></code> is an instance of <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">optional</span></code>.
 268             </li>
 269 <li class="listitem">
 270               <span class="bold"><strong>Example:</strong></span>
 271 <pre class="programlisting"><span class="keyword">int</span> <span class="identifier">a</span> <span class="special">=</span> <span class="number">1</span> <span class="special">;</span>
 272 <span class="keyword">int</span> <span class="identifier">b</span> <span class="special">=</span> <span class="number">2</span> <span class="special">;</span>
 273 <span class="identifier">T</span><span class="special">&amp;</span> <span class="identifier">ra</span> <span class="special">=</span> <span class="identifier">a</span> <span class="special">;</span>
 274 <span class="identifier">T</span><span class="special">&amp;</span> <span class="identifier">rb</span> <span class="special">=</span> <span class="identifier">b</span> <span class="special">;</span>
 275 <span class="identifier">optional</span><span class="special">&lt;</span><span class="keyword">int</span><span class="special">&amp;&gt;</span> <span class="identifier">def</span> <span class="special">;</span>
 276 <span class="identifier">optional</span><span class="special">&lt;</span><span class="keyword">int</span><span class="special">&amp;&gt;</span> <span class="identifier">opt</span><span class="special">(</span><span class="identifier">ra</span><span class="special">)</span> <span class="special">;</span>
 277
 278 <span class="identifier">def</span> <span class="special">=</span> <span class="identifier">rb</span> <span class="special">;</span> <span class="comment">// binds 'def' to 'b' through 'rb'</span>
 279 <span class="identifier">assert</span> <span class="special">(</span> <span class="special">*</span><span class="identifier">def</span> <span class="special">==</span> <span class="identifier">b</span> <span class="special">)</span> <span class="special">;</span>
 280 <span class="special">*</span><span class="identifier">def</span> <span class="special">=</span> <span class="identifier">a</span> <span class="special">;</span> <span class="comment">// changes the value of 'b' to a copy of the value of 'a'</span>
 281 <span class="identifier">assert</span> <span class="special">(</span> <span class="identifier">b</span> <span class="special">==</span> <span class="identifier">a</span> <span class="special">)</span> <span class="special">;</span>
 282 <span class="keyword">int</span> <span class="identifier">c</span> <span class="special">=</span> <span class="number">3</span><span class="special">;</span>
 283 <span class="keyword">int</span><span class="special">&amp;</span> <span class="identifier">rc</span> <span class="special">=</span> <span class="identifier">c</span> <span class="special">;</span>
 284 <span class="identifier">opt</span> <span class="special">=</span> <span class="identifier">rc</span> <span class="special">;</span> <span class="comment">// REBINDS to 'c' through 'rc'</span>
 285 <span class="identifier">c</span> <span class="special">=</span> <span class="number">4</span> <span class="special">;</span>
 286 <span class="identifier">assert</span> <span class="special">(</span> <span class="special">*</span><span class="identifier">opt</span> <span class="special">==</span> <span class="number">4</span> <span class="special">)</span> <span class="special">;</span>
 287 </pre>
 288             </li>
 289 </ul></div>
 290 <p>
 291           <span class="inlinemediaobject"><img src="../../../images/space.png" alt="space"></span>
 292         </p>
 293 <a name="reference_optional_ref_emplace_R"></a><div class="blockquote"><blockquote class="blockquote"><p>
 294             <code class="computeroutput"><span class="keyword">void</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&amp;&gt;::</span><span class="identifier">emplace</span><span class="special">(</span> <span class="identifier">R</span><span class="special">&amp;&amp;</span> <span class="identifier">r</span>
 295             <span class="special">)</span> <span class="keyword">noexcept</span>
 296             <span class="special">;</span></code>
 297           </p></blockquote></div>
 298 <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
 299 <li class="listitem">
 300               <span class="bold"><strong>Effects: </strong></span> Assigns <code class="computeroutput"><span class="identifier">ref</span></code>
 301               with expression <code class="computeroutput"><span class="identifier">r</span></code>.
 302             </li>
 303 <li class="listitem">
 304               <span class="bold"><strong>Postconditions:</strong></span> <code class="computeroutput"><span class="keyword">bool</span><span class="special">(*</span><span class="keyword">this</span><span class="special">)</span> <span class="special">==</span> <span class="keyword">true</span></code>.
 305             </li>
 306 <li class="listitem">
 307               <span class="bold"><strong>Remarks:</strong></span> Unless <code class="computeroutput"><span class="identifier">R</span></code>
 308               is an lvalue reference, the program is ill-formed. This function does
 309               not participate in overload resolution if <code class="computeroutput"><span class="identifier">decay</span><span class="special">&lt;</span><span class="identifier">R</span><span class="special">&gt;</span></code> is an instance of <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">optional</span></code>.
 310             </li>
 311 </ul></div>
 312 <p>
 313           <span class="inlinemediaobject"><img src="../../../images/space.png" alt="space"></span>
 314         </p>
 315 <a name="reference_optional_ref_get"></a><div class="blockquote"><blockquote class="blockquote"><p>
 316             <code class="computeroutput"><span class="identifier">T</span><span class="special">&amp;</span>
 317             <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&amp;&gt;::</span><span class="identifier">get</span><span class="special">()</span> <span class="keyword">const</span> <span class="special">;</span></code>
 318           </p></blockquote></div>
 319 <div class="blockquote"><blockquote class="blockquote"><p>
 320             <code class="computeroutput"><span class="identifier">T</span><span class="special">&amp;</span>
 321             <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&amp;&gt;::</span><span class="keyword">operator</span> <span class="special">*()</span>
 322             <span class="keyword">const</span> <span class="special">;</span></code>
 323           </p></blockquote></div>
 324 <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
 325 <li class="listitem">
 326               <span class="bold"><strong>Requires:</strong></span> <code class="computeroutput"><span class="keyword">bool</span><span class="special">(*</span><span class="keyword">this</span><span class="special">)</span> <span class="special">==</span> <span class="keyword">true</span></code>.
 327             </li>
 328 <li class="listitem">
 329               <span class="bold"><strong>Effects: </strong></span> Returns <code class="computeroutput"><span class="special">*</span><span class="identifier">ref</span></code>.
 330             </li>
 331 <li class="listitem">
 332               <span class="bold"><strong>Throws: </strong></span> Nothing.
 333             </li>
 334 <li class="listitem">
 335               <span class="bold"><strong>Example:</strong></span>
 336 <pre class="programlisting"><span class="identifier">T</span> <span class="identifier">v</span> <span class="special">;</span>
 337 <span class="identifier">T</span><span class="special">&amp;</span> <span class="identifier">vref</span> <span class="special">=</span> <span class="identifier">v</span> <span class="special">;</span>
 338 <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&amp;&gt;</span> <span class="identifier">opt</span> <span class="special">(</span> <span class="identifier">vref</span> <span class="special">);</span>
 339 <span class="identifier">T</span> <span class="keyword">const</span><span class="special">&amp;</span> <span class="identifier">vref2</span> <span class="special">=</span> <span class="special">*</span><span class="identifier">opt</span><span class="special">;</span>
 340 <span class="identifier">assert</span> <span class="special">(</span> <span class="identifier">vref2</span> <span class="special">==</span> <span class="identifier">v</span> <span class="special">)</span> <span class="special">;</span>
 341 <span class="special">++</span> <span class="identifier">v</span> <span class="special">;</span>
 342 <span class="identifier">assert</span> <span class="special">(</span> <span class="special">*</span><span class="identifier">opt</span> <span class="special">==</span> <span class="identifier">v</span> <span class="special">)</span> <span class="special">;</span>
 343 </pre>
 344             </li>
 345 </ul></div>
 346 <p>
 347           <span class="inlinemediaobject"><img src="../../../images/space.png" alt="space"></span>
 348         </p>
 349 <a name="reference_optional_ref_arrow"></a><div class="blockquote"><blockquote class="blockquote"><p>
 350             <code class="computeroutput"><span class="identifier">T</span><span class="special">*</span>
 351             <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&amp;&gt;::</span><span class="keyword">operator</span> <span class="special">-&gt;</span>
 352             <span class="special">()</span> <span class="keyword">const</span>
 353             <span class="special">;</span></code>
 354           </p></blockquote></div>
 355 <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
 356 <li class="listitem">
 357               <span class="bold"><strong>Requires:</strong></span> <code class="computeroutput"><span class="keyword">bool</span><span class="special">(*</span><span class="keyword">this</span><span class="special">)</span> <span class="special">==</span> <span class="keyword">true</span></code>.
 358             </li>
 359 <li class="listitem">
 360               <span class="bold"><strong>Effects: </strong></span> Returns <code class="computeroutput"><span class="identifier">ref</span></code>.
 361             </li>
 362 <li class="listitem">
 363               <span class="bold"><strong>Throws: </strong></span> Nothing.
 364             </li>
 365 </ul></div>
 366 <p>
 367           <span class="inlinemediaobject"><img src="../../../images/space.png" alt="space"></span>
 368         </p>
 369 <a name="reference_optional_ref_value"></a><div class="blockquote"><blockquote class="blockquote"><p>
 370             <code class="computeroutput"><span class="identifier">T</span><span class="special">&amp;</span>
 371             <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&amp;&gt;::</span><span class="identifier">value</span><span class="special">()</span> <span class="keyword">const</span> <span class="special">;</span></code>
 372           </p></blockquote></div>
 373 <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem">
 374               <span class="bold"><strong>Effects:</strong></span> Equivalent to <code class="computeroutput"><span class="keyword">return</span> <span class="keyword">bool</span><span class="special">(*</span><span class="keyword">this</span><span class="special">)</span> <span class="special">?</span> <span class="special">*</span><span class="identifier">val</span> <span class="special">:</span> <span class="keyword">throw</span> <span class="identifier">bad_optional_access</span><span class="special">();</span></code>.
 375             </li></ul></div>
 376 <p>
 377           <span class="inlinemediaobject"><img src="../../../images/space.png" alt="space"></span>
 378         </p>
 379 <a name="reference_optional_ref_value_or"></a><div class="blockquote"><blockquote class="blockquote"><p>
 380             <code class="computeroutput"><span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">R</span><span class="special">&gt;</span> <span class="identifier">T</span><span class="special">&amp;</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&amp;&gt;::</span><span class="identifier">value_or</span><span class="special">(</span> <span class="identifier">R</span><span class="special">&amp;&amp;</span> <span class="identifier">r</span>
 381             <span class="special">)</span> <span class="keyword">const</span>
 382             <span class="keyword">noexcept</span><span class="special">;</span></code>
 383           </p></blockquote></div>
 384 <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
 385 <li class="listitem">
 386               <span class="bold"><strong>Effects:</strong></span> Equivalent to <code class="computeroutput"><span class="keyword">if</span> <span class="special">(*</span><span class="keyword">this</span><span class="special">)</span> <span class="keyword">return</span> <span class="special">**</span><span class="keyword">this</span><span class="special">;</span> <span class="keyword">else</span> <span class="keyword">return</span>
 387               <span class="identifier">r</span><span class="special">;</span></code>.
 388             </li>
 389 <li class="listitem">
 390               <span class="bold"><strong>Remarks:</strong></span> Unless <code class="computeroutput"><span class="identifier">R</span></code>
 391               is an lvalue reference, the program is ill-formed.
 392             </li>
 393 </ul></div>
 394 <p>
 395           <span class="inlinemediaobject"><img src="../../../images/space.png" alt="space"></span>
 396         </p>
 397 <a name="reference_optional_ref_value_or_eval"></a><div class="blockquote"><blockquote class="blockquote"><p>
 398             <code class="computeroutput"><span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">F</span><span class="special">&gt;</span> <span class="identifier">T</span><span class="special">&amp;</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&amp;&gt;::</span><span class="identifier">value_or</span><span class="special">(</span> <span class="identifier">F</span> <span class="identifier">f</span> <span class="special">)</span> <span class="keyword">const</span> <span class="special">;</span></code>
 399           </p></blockquote></div>
 400 <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
 401 <li class="listitem">
 402               <span class="bold"><strong>Effects:</strong></span> Equivalent to <code class="computeroutput"><span class="keyword">if</span> <span class="special">(*</span><span class="keyword">this</span><span class="special">)</span> <span class="keyword">return</span> <span class="special">**</span><span class="keyword">this</span><span class="special">;</span> <span class="keyword">else</span> <span class="keyword">return</span>
 403               <span class="identifier">f</span><span class="special">();</span></code>.
 404             </li>
 405 <li class="listitem">
 406               <span class="bold"><strong>Remarks:</strong></span> Unless <code class="computeroutput"><span class="keyword">decltype</span><span class="special">(</span><span class="identifier">f</span><span class="special">())</span></code> is an lvalue reference, the program
 407               is ill-formed.
 408             </li>
 409 </ul></div>
 410 <p>
 411           <span class="inlinemediaobject"><img src="../../../images/space.png" alt="space"></span>
 412         </p>
 413 <a name="reference_optional_ref_get_ptr"></a><div class="blockquote"><blockquote class="blockquote"><p>
 414             <code class="computeroutput"><span class="identifier">T</span><span class="special">*</span>
 415             <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&amp;&gt;::</span><span class="identifier">get_ptr</span> <span class="special">()</span>
 416             <span class="keyword">const</span> <span class="keyword">noexcept</span><span class="special">;</span></code>
 417           </p></blockquote></div>
 418 <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem">
 419               <span class="bold"><strong>Returns:</strong></span> <code class="computeroutput"><span class="identifier">ref</span></code>.
 420             </li></ul></div>
 421 <p>
 422           <span class="inlinemediaobject"><img src="../../../images/space.png" alt="space"></span>
 423         </p>
 424 <a name="reference_optional_ref_operator_bool"></a><div class="blockquote"><blockquote class="blockquote"><p>
 425             <code class="computeroutput"><span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&amp;&gt;::</span><span class="keyword">operator</span> <span class="keyword">bool</span>
 426             <span class="special">()</span> <span class="keyword">const</span>
 427             <span class="keyword">noexcept</span><span class="special">;</span></code>
 428           </p></blockquote></div>
 429 <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem">
 430               <span class="bold"><strong>Returns:</strong></span> <code class="computeroutput"><span class="keyword">bool</span><span class="special">(</span><span class="identifier">ref</span><span class="special">)</span></code>.
 431             </li></ul></div>
 432 <p>
 433           <span class="inlinemediaobject"><img src="../../../images/space.png" alt="space"></span>
 434         </p>
 435 <a name="reference_optional_ref_operator_not"></a><div class="blockquote"><blockquote class="blockquote"><p>
 436             <code class="computeroutput"><span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&amp;&gt;::</span><span class="keyword">operator</span> <span class="special">!</span> <span class="special">()</span> <span class="keyword">const</span> <span class="keyword">noexcept</span><span class="special">;</span></code>
 437           </p></blockquote></div>
 438 <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem">
 439               <span class="bold"><strong>Returns:</strong></span> <code class="computeroutput"><span class="special">!</span><span class="keyword">bool</span><span class="special">(</span><span class="identifier">ref</span><span class="special">)</span></code>.
 440             </li></ul></div>
 441 <p>
 442           <span class="inlinemediaobject"><img src="../../../images/space.png" alt="space"></span>
 443         </p>
 444 <a name="reference_optional_ref_reset"></a><div class="blockquote"><blockquote class="blockquote"><p>
 445             <code class="computeroutput"><span class="keyword">void</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&amp;&gt;::</span><span class="identifier">reset</span><span class="special">()</span> <span class="keyword">noexcept</span><span class="special">;</span></code>
 446           </p></blockquote></div>
 447 <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
 448 <li class="listitem">
 449               <span class="bold"><strong>Effects:</strong></span> Use <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span> <span class="special">=</span> <span class="identifier">none</span></code> instead.
 450             </li>
 451 <li class="listitem">
 452               <span class="bold"><strong>Remarks:</strong></span> This function is depprecated.
 453             </li>
 454 </ul></div>
 455 <p>
 456           <span class="inlinemediaobject"><img src="../../../images/space.png" alt="space"></span>
 457         </p>
 458 <a name="reference_optional_ref_reset_value"></a><div class="blockquote"><blockquote class="blockquote"><p>
 459             <code class="computeroutput"><span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">R</span><span class="special">&gt;</span> <span class="keyword">void</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&amp;&gt;::</span><span class="identifier">reset</span> <span class="special">(</span> <span class="identifier">R</span><span class="special">&amp;&amp;</span>
 460             <span class="identifier">r</span><span class="special">)</span>
 461             <span class="keyword">noexcept</span><span class="special">;</span></code>
 462           </p></blockquote></div>
 463 <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
 464 <li class="listitem">
 465               <span class="bold"><strong>Effects:</strong></span> Equivalent to <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span> <span class="special">=</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">forward</span><span class="special">&lt;</span><span class="identifier">R</span><span class="special">&gt;(</span><span class="identifier">r</span><span class="special">)</span></code>.
 466             </li>
 467 <li class="listitem">
 468               <span class="bold"><strong>Remarks:</strong></span> This function is depprecated.
 469             </li>
 470 </ul></div>
 471 <p>
 472           <span class="inlinemediaobject"><img src="../../../images/space.png" alt="space"></span>
 473         </p>
 474 <a name="reference_optional_ref_is_initialized"></a><div class="blockquote"><blockquote class="blockquote"><p>
 475             <code class="computeroutput"><span class="keyword">bool</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&amp;&gt;::</span><span class="identifier">is_initialized</span><span class="special">()</span> <span class="keyword">const</span> <span class="keyword">noexcept</span><span class="special">;</span></code>
 476           </p></blockquote></div>
 477 <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
 478 <li class="listitem">
 479               <span class="bold"><strong>Effects:</strong></span> Equivalent to <code class="computeroutput"><span class="keyword">return</span> <span class="keyword">bool</span><span class="special">(*</span><span class="keyword">this</span><span class="special">)</span></code>.
 480             </li>
 481 <li class="listitem">
 482               <span class="bold"><strong>Remarks:</strong></span> This function is depprecated.
 483             </li>
 484 </ul></div>
 485 <p>
 486           <span class="inlinemediaobject"><img src="../../../images/space.png" alt="space"></span>
 487         </p>
 488 <a name="reference_optional_ref_get_value_or_value"></a><div class="blockquote"><blockquote class="blockquote"><p>
 489             <code class="computeroutput"><span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">R</span><span class="special">&gt;</span> <span class="identifier">T</span><span class="special">&amp;</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&amp;&gt;::</span><span class="identifier">get_value_or</span><span class="special">(</span> <span class="identifier">R</span><span class="special">&amp;&amp;</span> <span class="identifier">r</span>
 490             <span class="special">)</span> <span class="keyword">const</span>
 491             <span class="keyword">noexcept</span><span class="special">;</span></code>
 492           </p></blockquote></div>
 493 <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
 494 <li class="listitem">
 495               <span class="bold"><strong>Effects:</strong></span> Equivalent to <code class="computeroutput"><span class="keyword">return</span> <span class="identifier">value_or</span><span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">forward</span><span class="special">&lt;</span><span class="identifier">R</span><span class="special">&gt;(</span><span class="identifier">r</span><span class="special">);</span></code>.
 496             </li>
 497 <li class="listitem">
 498               <span class="bold"><strong>Remarks:</strong></span> This function is depprecated.
 499             </li>
 500 </ul></div>
 501 </div>
 502 <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
 503 <td align="left"></td>
 504 <td align="right"><div class="copyright-footer">Copyright &#169; 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright &#169; 2014-2016 Andrzej Krzemie&#324;ski<p>
 505         Distributed under the Boost Software License, Version 1.0. (See accompanying
 506         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>)
 507       </p>
 508 </div></td>
 509 </tr></table>
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