1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>Class template optional_manipulator</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="Chapter 1. Boost.Log v2"> 8<link rel="up" href="../../utilities.html#header.boost.log.utility.manipulators.optional_hpp" title="Header <boost/log/utility/manipulators/optional.hpp>"> 9<link rel="prev" href="dump_ele_idm46079573655296.html" title="Function template dump_elements"> 10<link rel="next" href="optional_idm46079573636736.html" title="Class template optional_manipulator<OptionalT, void>"> 11</head> 12<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> 13<table cellpadding="2" width="100%"><tr><td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../../../boost.png"></td></tr></table> 14<hr> 15<div class="spirit-nav"> 16<a accesskey="p" href="dump_ele_idm46079573655296.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../../utilities.html#header.boost.log.utility.manipulators.optional_hpp"><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="optional_idm46079573636736.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a> 17</div> 18<div class="refentry"> 19<a name="boost.log.optional_manipulator"></a><div class="titlepage"></div> 20<div class="refnamediv"> 21<h2><span class="refentrytitle">Class template optional_manipulator</span></h2> 22<p>boost::log::optional_manipulator</p> 23</div> 24<h2 xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv-title">Synopsis</h2> 25<div xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv"><pre class="synopsis"><span class="comment">// In header: <<a class="link" href="../../utilities.html#header.boost.log.utility.manipulators.optional_hpp" title="Header <boost/log/utility/manipulators/optional.hpp>">boost/log/utility/manipulators/optional.hpp</a>> 26 27</span><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> OptionalT<span class="special">,</span> <span class="keyword">typename</span> NoneT<span class="special">></span> 28<span class="keyword">class</span> <a class="link" href="optional_manipulator.html" title="Class template optional_manipulator">optional_manipulator</a> <span class="special">{</span> 29<span class="keyword">public</span><span class="special">:</span> 30 <span class="comment">// <a class="link" href="optional_manipulator.html#boost.log.optional_manipulatorconstruct-copy-destruct">construct/copy/destruct</a></span> 31 <a class="link" href="optional_manipulator.html#idm46079573638976-bb"><span class="identifier">optional_manipulator</span></a><span class="special">(</span><span class="identifier">stored_optional_type</span><span class="special">,</span> <span class="identifier">stored_none_type</span><span class="special">)</span> <span class="keyword">noexcept</span><span class="special">;</span> 32 33 <span class="comment">// <a class="link" href="optional_manipulator.html#idm46079573642704-bb">public member functions</a></span> 34 <span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> StreamT<span class="special">></span> <span class="keyword">void</span> <a class="link" href="optional_manipulator.html#idm46079573642144-bb"><span class="identifier">output</span></a><span class="special">(</span><span class="identifier">StreamT</span> <span class="special">&</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span> 35<span class="special">}</span><span class="special">;</span></pre></div> 36<div class="refsect1"> 37<a name="idm44984854354464"></a><h2>Description</h2> 38<p>Stream manipulator for inserting an optional value. </p> 39<div class="refsect2"> 40<a name="idm44984854353728"></a><h3> 41<a name="boost.log.optional_manipulatorconstruct-copy-destruct"></a><code class="computeroutput">optional_manipulator</code> 42 public 43 construct/copy/destruct</h3> 44<div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem"> 45<pre class="literallayout"><a name="idm46079573638976-bb"></a><span class="identifier">optional_manipulator</span><span class="special">(</span><span class="identifier">stored_optional_type</span> opt<span class="special">,</span> <span class="identifier">stored_none_type</span> none<span class="special">)</span> <span class="keyword">noexcept</span><span class="special">;</span></pre>Initializing constructor. </li></ol></div> 46</div> 47<div class="refsect2"> 48<a name="idm44984854344896"></a><h3> 49<a name="idm46079573642704-bb"></a><code class="computeroutput">optional_manipulator</code> public member functions</h3> 50<div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem"> 51<pre class="literallayout"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> StreamT<span class="special">></span> <span class="keyword">void</span> <a name="idm46079573642144-bb"></a><span class="identifier">output</span><span class="special">(</span><span class="identifier">StreamT</span> <span class="special">&</span> stream<span class="special">)</span> <span class="keyword">const</span><span class="special">;</span></pre>The method outputs the value, if it is present, otherwise outputs the "none" marker. </li></ol></div> 52</div> 53<div class="refsect2"> 54<a name="idm44984854333600"></a><h3>Specializations</h3> 55<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p><a class="link" href="optional_idm46079573636736.html" title="Class template optional_manipulator<OptionalT, void>">Class template optional_manipulator<OptionalT, void></a></p></li></ul></div> 56</div> 57</div> 58</div> 59<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 60<td align="left"></td> 61<td align="right"><div class="copyright-footer">Copyright © 2007-2019 Andrey Semashev<p> 62 Distributed under the Boost Software License, Version 1.0. (See accompanying 63 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>). 64 </p> 65</div></td> 66</tr></table> 67<hr> 68<div class="spirit-nav"> 69<a accesskey="p" href="dump_ele_idm46079573655296.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../../utilities.html#header.boost.log.utility.manipulators.optional_hpp"><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="optional_idm46079573636736.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a> 70</div> 71</body> 72</html> 73
