1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>Getting Started</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.Convert 2.0"> 8<link rel="up" href="../index.html" title="Chapter 1. Boost.Convert 2.0"> 9<link rel="prev" href="introduction.html" title="Introduction"> 10<link rel="next" href="getting_started/flexibility_and_adaptability_to_change.html" title="Flexibility and Adaptability to Change"> 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="introduction.html"><img 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Change</a></span></dt> 34<dt><span class="section"><a href="getting_started/basic_conversion_failure_detection.html">Basic 35 Conversion-Failure Detection</a></span></dt> 36</dl></div> 37<div class="note"><table border="0" summary="Note"> 38<tr> 39<td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../../../../../doc/src/images/note.png"></td> 40<th align="left">Note</th> 41</tr> 42<tr><td align="left" valign="top"><p> 43 Given the ubiquity of <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">lexical_cast</span></code> 44 and the familiarity of the programming community with it, here and further 45 in the documentation <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">lexical_cast</span></code> 46 is often mentioned as a reference. 47 </p></td></tr> 48</table></div> 49<div class="section"> 50<div class="titlepage"><div><div><h3 class="title"> 51<a name="boost_convert.getting_started.basic_deployment"></a><a class="link" href="getting_started.html#boost_convert.getting_started.basic_deployment" title="Basic Deployment">Basic 52 Deployment</a> 53</h3></div></div></div> 54<p> 55 For die-hard <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">lexical_cast</span></code> users or as a transitional 56 path to <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">convert</span></code>, one of <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">convert</span></code> 57 deployments is not that different from <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">lexical_cast</span></code>. 58 In fact, the original <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">lexical_cast</span></code> 59 functionality is easily deployed through <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">convert</span></code> 60 interface: 61 </p> 62<p> 63</p> 64<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">convert</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 65<span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">convert</span><span class="special">/</span><span class="identifier">lexical_cast</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 66</pre> 67<p> 68 </p> 69<p> 70</p> 71<pre class="programlisting"><span class="keyword">using</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span><span class="special">;</span> 72<span class="keyword">using</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">lexical_cast</span><span class="special">;</span> 73<span class="keyword">using</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">convert</span><span class="special">;</span> 74</pre> 75<p> 76 </p> 77<p> 78</p> 79<pre class="programlisting"><span class="comment">// Definition of the default converter (optional)</span> 80<span class="keyword">struct</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">cnv</span><span class="special">::</span><span class="identifier">by_default</span> <span class="special">:</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">cnv</span><span class="special">::</span><span class="identifier">lexical_cast</span> <span class="special">{};</span> 81</pre> 82<p> 83 </p> 84<p> 85</p> 86<pre class="programlisting"><span class="keyword">try</span> 87<span class="special">{</span> 88 <span class="identifier">boost</span><span class="special">::</span><span class="identifier">cnv</span><span class="special">::</span><span class="identifier">lexical_cast</span> <span class="identifier">cnv</span><span class="special">;</span> <span class="comment">// boost::lexical_cast-based converter</span> 89 90 <span class="keyword">int</span> <span class="identifier">i1</span> <span class="special">=</span> <span class="identifier">lexical_cast</span><span class="special"><</span><span class="keyword">int</span><span class="special">>(</span><span class="string">"123"</span><span class="special">);</span> <span class="comment">// boost::lexical_cast standard deployment</span> 91 <span class="keyword">int</span> <span class="identifier">i2</span> <span class="special">=</span> <span class="identifier">convert</span><span class="special"><</span><span class="keyword">int</span><span class="special">>(</span><span class="string">"123"</span><span class="special">).</span><span class="identifier">value</span><span class="special">();</span> <span class="comment">// boost::convert with the default converter</span> 92 <span class="keyword">int</span> <span class="identifier">i3</span> <span class="special">=</span> <span class="identifier">convert</span><span class="special"><</span><span class="keyword">int</span><span class="special">>(</span><span class="string">"123"</span><span class="special">,</span> <span class="identifier">cnv</span><span class="special">).</span><span class="identifier">value</span><span class="special">();</span> <span class="comment">// boost::convert with an explicit converter</span> 93 <span class="identifier">string</span> <span class="identifier">s1</span> <span class="special">=</span> <span class="identifier">lexical_cast</span><span class="special"><</span><span class="identifier">string</span><span class="special">>(</span><span class="number">123</span><span class="special">);</span> <span class="comment">// boost::lexical_cast standard deployment</span> 94 <span class="identifier">string</span> <span class="identifier">s2</span> <span class="special">=</span> <span class="identifier">convert</span><span class="special"><</span><span class="identifier">string</span><span class="special">>(</span><span class="number">123</span><span class="special">).</span><span class="identifier">value</span><span class="special">();</span> <span class="comment">// boost::convert with the default converter</span> 95 <span class="identifier">string</span> <span class="identifier">s3</span> <span class="special">=</span> <span class="identifier">convert</span><span class="special"><</span><span class="identifier">string</span><span class="special">>(</span><span class="number">123</span><span class="special">,</span> <span class="identifier">cnv</span><span class="special">).</span><span class="identifier">value</span><span class="special">();</span> <span class="comment">// boost::convert with an explicit converter</span> 96 97 <span class="identifier">BOOST_TEST</span><span class="special">(</span><span class="identifier">i1</span> <span class="special">==</span> <span class="number">123</span><span class="special">);</span> 98 <span class="identifier">BOOST_TEST</span><span class="special">(</span><span class="identifier">i2</span> <span class="special">==</span> <span class="number">123</span><span class="special">);</span> 99 <span class="identifier">BOOST_TEST</span><span class="special">(</span><span class="identifier">i3</span> <span class="special">==</span> <span class="number">123</span><span class="special">);</span> 100 <span class="identifier">BOOST_TEST</span><span class="special">(</span><span class="identifier">s1</span> <span class="special">==</span> <span class="string">"123"</span><span class="special">);</span> 101 <span class="identifier">BOOST_TEST</span><span class="special">(</span><span class="identifier">s2</span> <span class="special">==</span> <span class="string">"123"</span><span class="special">);</span> 102 <span class="identifier">BOOST_TEST</span><span class="special">(</span><span class="identifier">s3</span> <span class="special">==</span> <span class="string">"123"</span><span class="special">);</span> 103<span class="special">}</span> 104<span class="keyword">catch</span> <span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">exception</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">ex</span><span class="special">)</span> 105<span class="special">{</span> 106 <span class="comment">// Please be aware that the conversion requests above can fail.</span> 107 <span class="comment">// Use try'n'catch blocks to handle any exceptions thrown.</span> 108 <span class="comment">// Ignore this at your peril!</span> 109 <span class="identifier">std</span><span class="special">::</span><span class="identifier">cerr</span> <span class="special"><<</span> <span class="string">"Exception "</span> <span class="special"><<</span> <span class="identifier">ex</span><span class="special">.</span><span class="identifier">what</span><span class="special">()</span> <span class="special"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span> 110<span class="special">}</span> 111</pre> 112<p> 113 </p> 114<div class="important"><table border="0" summary="Important"> 115<tr> 116<td rowspan="2" align="center" valign="top" width="25"><img alt="[Important]" src="../../../../../doc/src/images/important.png"></td> 117<th align="left">Important</th> 118</tr> 119<tr><td align="left" valign="top"><p> 120 As we explore <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">convert</span></code> behavior and interface further, 121 at first they might appear unduly complex, verbose, etc... nothing like 122 <code class="computeroutput"><span class="identifier">atoi</span><span class="special">()</span></code>... 123 so famous for all the wrong reasons. :-) It is important to remember that 124 a conversion request is only a <span class="emphasis"><em>request</em></span> which may succeed 125 but may also fail... which might not be as rare or as exceptional as one 126 might hope. <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">convert</span></code> (as well as <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">lexical_cast</span></code>) 127 behavior and interfaces reflect that reality. 128 </p></td></tr> 129</table></div> 130</div> 131</div> 132<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 133<td align="left"></td> 134<td align="right"><div class="copyright-footer">Copyright © 2009-2016 Vladimir Batov<p> 135 Distributed under the Boost Software License, Version 1.0. See copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>. 136 </p> 137</div></td> 138</tr></table> 139<hr> 140<div class="spirit-nav"> 141<a accesskey="p" href="introduction.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.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="getting_started/flexibility_and_adaptability_to_change.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a> 142</div> 143</body> 144</html> 145
