1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>Detailed semantics</title> 5<link rel="stylesheet" href="../../../../../../../doc/src/boostbook.css" type="text/css"> 6<meta name="generator" content="DocBook XSL Stylesheets V1.79.1"> 7<link rel="home" href="../../../index.html" title="Boost.Optional"> 8<link rel="up" href="../io_header.html" title="Header <boost/optional/optional_io.hpp>"> 9<link rel="prev" href="../io_header.html" title="Header <boost/optional/optional_io.hpp>"> 10<link rel="next" href="../header__boost_optional_optional_fwd_hpp_.html" title="Header <boost/optional/optional_fwd.hpp>"> 11</head> 12<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> 13<table cellpadding="2" width="100%"><tr> 14<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../../../../boost.png"></td> 15<td align="center"><a href="../../../../../../../index.html">Home</a></td> 16<td align="center"><a href="../../../../../../../libs/libraries.htm">Libraries</a></td> 17<td align="center"><a href="http://www.boost.org/users/people.html">People</a></td> 18<td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td> 19<td align="center"><a href="../../../../../../../more/index.htm">More</a></td> 20</tr></table> 21<hr> 22<div class="spirit-nav"> 23<a accesskey="p" href="../io_header.html"><img src="../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../io_header.html"><img src="../../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../../index.html"><img src="../../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="../header__boost_optional_optional_fwd_hpp_.html"><img src="../../../../../../../doc/src/images/next.png" alt="Next"></a> 24</div> 25<div class="section"> 26<div class="titlepage"><div><div><h4 class="title"> 27<a name="boost_optional.reference.io_header.io_semantics"></a><a class="link" href="io_semantics.html" title="Detailed semantics">Detailed 28 semantics</a> 29</h4></div></div></div> 30<p> 31 <a name="reference_operator_ostream"></a><code class="computeroutput"><span class="keyword">template</span> 32 <span class="special"><</span><span class="keyword">class</span> 33 <span class="identifier">CharType</span><span class="special">,</span> 34 <span class="keyword">class</span> <span class="identifier">CharTrait</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">T</span><span class="special">></span></code> 35 <br> <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">basic_ostream</span><span class="special"><</span><span class="identifier">CharType</span><span class="special">,</span> <span class="identifier">CharTrait</span><span class="special">>&</span></code> <br> <code class="computeroutput"><span class="keyword">operator</span><span class="special"><<(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">basic_ostream</span><span class="special"><</span><span class="identifier">CharType</span><span class="special">,</span> <span class="identifier">CharTrait</span><span class="special">>&</span> 36 <span class="identifier">out</span><span class="special">,</span> 37 <span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">></span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">v</span><span class="special">);</span></code> 38 </p> 39<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> 40<li class="listitem"> 41 <span class="bold"><strong>Effect:</strong></span> Outputs an implementation-defined 42 string. The output contains the information about whether the optional 43 object contains a value or not. If <code class="computeroutput"><span class="identifier">v</span></code> 44 contains a value, the output contains result of calling <code class="computeroutput"><span class="identifier">out</span> <span class="special"><<</span> 45 <span class="special">*</span><span class="identifier">v</span></code>. 46 </li> 47<li class="listitem"> 48 <span class="bold"><strong>Returns:</strong></span> <code class="computeroutput"><span class="identifier">out</span></code>. 49 </li> 50</ul></div> 51<p> 52 <span class="inlinemediaobject"><img src="../../../images/space.png" alt="space"></span> <a name="reference_operator_ostream_none"></a> 53 </p> 54<p> 55 <code class="computeroutput"><span class="keyword">template</span> <span class="special"><</span><span class="keyword">class</span> <span class="identifier">CharType</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">CharTrait</span><span class="special">,</span> 56 <span class="keyword">class</span> <span class="identifier">T</span><span class="special">></span></code> <br> <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">basic_ostream</span><span class="special"><</span><span class="identifier">CharType</span><span class="special">,</span> <span class="identifier">CharTrait</span><span class="special">>&</span></code> 57 <br> <code class="computeroutput"><span class="keyword">operator</span><span class="special"><<(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">basic_ostream</span><span class="special"><</span><span class="identifier">CharType</span><span class="special">,</span> <span class="identifier">CharTrait</span><span class="special">>&</span> <span class="identifier">out</span><span class="special">,</span> <span class="identifier">none_t</span><span class="special">);</span></code> 58 </p> 59<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> 60<li class="listitem"> 61 <span class="bold"><strong>Effect:</strong></span> Outputs an implementation-defined 62 string. 63 </li> 64<li class="listitem"> 65 <span class="bold"><strong>Returns:</strong></span> <code class="computeroutput"><span class="identifier">out</span></code>. 66 </li> 67</ul></div> 68<p> 69 <span class="inlinemediaobject"><img src="../../../images/space.png" alt="space"></span> <a name="reference_operator_istream"></a> 70 </p> 71<p> 72 <code class="computeroutput"><span class="keyword">template</span> <span class="special"><</span><span class="keyword">class</span> <span class="identifier">CharType</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">CharTrait</span><span class="special">,</span> 73 <span class="keyword">class</span> <span class="identifier">T</span><span class="special">></span></code> <br> <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">basic_ostream</span><span class="special"><</span><span class="identifier">CharType</span><span class="special">,</span> <span class="identifier">CharTrait</span><span class="special">>&</span></code> 74 <br> <code class="computeroutput"><span class="keyword">operator</span><span class="special">>>(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">basic_istream</span><span class="special"><</span><span class="identifier">CharType</span><span class="special">,</span> <span class="identifier">CharTrait</span><span class="special">>&</span> <span class="identifier">in</span><span class="special">,</span> <span class="identifier">optional</span><span class="special"><</span><span class="identifier">T</span><span class="special">>&</span> <span class="identifier">v</span><span class="special">);</span></code> 75 </p> 76<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> 77<li class="listitem"> 78 <span class="bold"><strong>Requires:</strong></span> <code class="computeroutput"><span class="identifier">T</span></code> 79 is <a href="http://www.sgi.com/tech/stl/DefaultConstructible.html" target="_top"><code class="computeroutput"><span class="identifier">DefaultConstructible</span></code></a> and 80 <code class="computeroutput"><span class="identifier">MoveConstructible</span></code>. 81 </li> 82<li class="listitem"> 83 <span class="bold"><strong>Effect:</strong></span> Reads the value of optional 84 object from <code class="computeroutput"><span class="identifier">in</span></code>. If 85 the string representation indicates that the optional object should 86 contain a value, <code class="computeroutput"><span class="identifier">v</span></code> 87 contains a value and its contained value is obtained as if by default-constructing 88 an object <code class="computeroutput"><span class="identifier">o</span></code> of type 89 <code class="computeroutput"><span class="identifier">T</span></code> and then calling 90 <code class="computeroutput"><span class="identifier">in</span> <span class="special">>></span> 91 <span class="identifier">o</span></code>; otherwise <code class="computeroutput"><span class="identifier">v</span></code> does not contain a value, and the 92 previously contained value (if any) has been destroyed. 93 </li> 94<li class="listitem"> 95 <span class="bold"><strong>Returns:</strong></span> <code class="computeroutput"><span class="identifier">out</span></code>. 96 </li> 97</ul></div> 98</div> 99<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 100<td align="left"></td> 101<td align="right"><div class="copyright-footer">Copyright © 2003-2007 Fernando Luis Cacciola Carballal<br>Copyright © 2014-2018 Andrzej Krzemieński<p> 102 Distributed under the Boost Software License, Version 1.0. (See accompanying 103 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>) 104 </p> 105</div></td> 106</tr></table> 107<hr> 108<div class="spirit-nav"> 109<a accesskey="p" href="../io_header.html"><img src="../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../io_header.html"><img src="../../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../../index.html"><img src="../../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="../header__boost_optional_optional_fwd_hpp_.html"><img src="../../../../../../../doc/src/images/next.png" alt="Next"></a> 110</div> 111</body> 112</html> 113
