libs/utility/CopyConstructible.html


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  <title>Copy Constructible</title>
</head>

<body bgcolor="#FFFFFF" link="#0000EE" text="#000000" vlink="#551A8B" alink=
"#FF0000">
  <img src="../../boost.png" alt="C++ Boost" width="277" height=
  "86"><br clear="none">

  <h1>Copy Constructible</h1>

  <h3>Description</h3>

  <p>A type is Copy Constructible if it is possible to copy objects of that
  type.</p>

  <h3>Notation</h3>

  <table summary="">
    <tr>
      <td valign="top"><tt>T</tt></td>

      <td valign="top">is type that is a model of Copy Constructible</td>
    </tr>

    <tr>
      <td valign="top"><tt>t</tt></td>

      <td valign="top">is an object of type <tt>T</tt></td>
    </tr>

    <tr>
      <td valign="top"><tt>u</tt></td>

      <td valign="top">is an object of type <tt>const T</tt></td>
    </tr>
  </table>

  <h3>Definitions</h3>

  <h3>Valid expressions</h3>

  <table border summary="">
    <tr>
      <th>Name</th>

      <th>Expression</th>

      <th>Return type</th>

      <th>Semantics</th>
    </tr>

    <tr>
      <td valign="top">Copy constructor</td>

      <td valign="top"><tt>T(t)</tt></td>

      <td valign="top"><tt>T</tt></td>

      <td valign="top"><tt>t</tt> is equivalent to <tt>T(t)</tt></td>
    </tr>

    <tr>
      <td valign="top">Copy constructor</td>

      <td valign="top">
        <pre>
T(u)
</pre>
      </td>

      <td valign="top"><tt>T</tt></td>

      <td valign="top"><tt>u</tt> is equivalent to <tt>T(u)</tt></td>
    </tr>

    <tr>
      <td valign="top">Destructor</td>

      <td valign="top">
        <pre>
t.~T()
</pre>
      </td>

      <td valign="top"><tt>T</tt></td>

      <td valign="top">&nbsp;</td>
    </tr>

    <tr>
      <td valign="top">Address Operator</td>

      <td valign="top">
        <pre>
&amp;t
</pre>
      </td>

      <td valign="top"><tt>T*</tt></td>

      <td valign="top">denotes the address of <tt>t</tt></td>
    </tr>

    <tr>
      <td valign="top">Address Operator</td>

      <td valign="top">
        <pre>
&amp;u
</pre>
      </td>

      <td valign="top"><tt>T*</tt></td>

      <td valign="top">denotes the address of <tt>u</tt></td>
    </tr>
  </table>

  <h3>Models</h3>

  <ul>
    <li><tt>int</tt></li>

    <li><tt>std::pair</tt></li>
  </ul>

  <h3>Concept Checking Class</h3>
  <pre>
  template &lt;class T&gt;
  struct CopyConstructibleConcept
  {
    void constraints() {
      T a(b);            // require copy constructor
      T* ptr = &amp;a;       // require address of operator
      const_constraints(a);
      ignore_unused_variable_warning(ptr);
    }
    void const_constraints(const T&amp; a) {
      T c(a);            // require const copy constructor
      const T* ptr = &amp;a; // require const address of operator
      ignore_unused_variable_warning(c);
      ignore_unused_variable_warning(ptr);
    }
    T b;
  };
</pre>

  <h3>See also</h3>

  <p><a href="http://www.sgi.com/tech/stl/DefaultConstructible.html">Default
  Constructible</a> and <a href="./Assignable.html">Assignable</a><br></p>
  <hr>

  <p><a href="http://validator.w3.org/check?uri=referer"><img border="0" src=
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  <p>Revised 
  <!--webbot bot="Timestamp" s-type="EDITED" s-format="%d %B, %Y" startspan -->05
  December, 2006<!--webbot bot="Timestamp" endspan i-checksum="38516" --></p>

  <table summary="">
    <tr valign="top">
      <td nowrap><i>Copyright &copy; 2000</i></td>

      <td><i><a href="http://www.lsc.nd.edu/~jsiek">Jeremy Siek</a>, Univ.of
      Notre Dame (<a href=
      "mailto:jsiek@lsc.nd.edu">jsiek@lsc.nd.edu</a>)</i></td>
    </tr>
  </table>

  <p><i>Distributed under the Boost Software License, Version 1.0. (See
  accompanying file <a href="../../LICENSE_1_0.txt">LICENSE_1_0.txt</a> or
  copy at <a href=
  "http://www.boost.org/LICENSE_1_0.txt">http://www.boost.org/LICENSE_1_0.txt</a>)</i></p>
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