1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>Strings and C-strings comparison</title> 5<link rel="stylesheet" href="../../../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.Test"> 8<link rel="up" href="../extended_comparison.html" title="Extended comparisons support"> 9<link rel="prev" href="floating_point/floating_points_comparison_theory.html" title="Theory behind floating point comparisons"> 10<link rel="next" href="collections.html" title="Collections comparison"> 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="floating_point/floating_points_comparison_theory.html"><img src="../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../extended_comparison.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="collections.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_test.testing_tools.extended_comparison.strings"></a><a class="link" href="strings.html" title="Strings and C-strings comparison">Strings 28 and C-strings comparison</a> 29</h4></div></div></div> 30<p> 31 In the general case, pointers are compared using their value. However when 32 type of the the pointers are <code class="computeroutput"><span class="keyword">char</span><span class="special">*</span></code> or <code class="computeroutput"><span class="keyword">wchar_t</span><span class="special">*</span></code>, <a class="link" href="../../utf_reference/testing_tool_ref/assertion_boost_test_universal_macro.html" title="BOOST_TEST"><code class="computeroutput"><span class="identifier">BOOST_TEST</span></code></a> promotes them as null 33 terminated <code class="computeroutput"><span class="keyword">char</span></code> arrays and 34 string comparison is used instead. <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span></code> 35 (or any <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">basic_string</span></code>) and <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">string_view</span></code> 36 (or any <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">basic_string_view</span></code>) are eligible for string 37 comparison. 38 </p> 39<p> 40 String comparison can be used only if the operands to compare in <a class="link" href="../../utf_reference/testing_tool_ref/assertion_boost_test_universal_macro.html" title="BOOST_TEST"><code class="computeroutput"><span class="identifier">BOOST_TEST</span></code></a> can both be considered 41 as strings type. 42 </p> 43<div class="tip"><table border="0" summary="Tip"> 44<tr> 45<td rowspan="2" align="center" valign="top" width="25"><img alt="[Tip]" src="../../../../../../../doc/src/images/tip.png"></td> 46<th align="left">Tip</th> 47</tr> 48<tr><td align="left" valign="top"><p> 49 In this form, the comparison method and reporting can be overridden by 50 providing an additional argument to <a class="link" href="../../utf_reference/testing_tool_ref/assertion_boost_test_universal_macro.html" title="BOOST_TEST"><code class="computeroutput"><span class="identifier">BOOST_TEST</span></code></a>. See the <a class="link" href="collections.html" title="Collections comparison">collection 51 comparison</a> section for more details, in particular <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">test_tools</span><span class="special">::</span><span class="identifier">per_element</span><span class="special">()</span></code> 52 and <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">test_tools</span><span class="special">::</span><span class="identifier">lexicographic</span><span class="special">()</span></code> 53 modifiers. 54 </p></td></tr> 55</table></div> 56<h6> 57<a name="boost_test.testing_tools.extended_comparison.strings.h0"></a> 58 <span class="phrase"><a name="boost_test.testing_tools.extended_comparison.strings.example_descr"></a></span><a class="link" href="strings.html#boost_test.testing_tools.extended_comparison.strings.example_descr">Example: 59 BOOST_TEST string comparison</a> 60 </h6> 61<div class="informaltable"><table class="table"> 62<colgroup><col></colgroup> 63<thead><tr><th> 64 <p> 65 Code 66 </p> 67 </th></tr></thead> 68<tbody><tr><td> 69<pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"><span class="preprocessor">#define</span> <span class="identifier">BOOST_TEST_MODULE</span> <span class="identifier">boost_test_strings</span> 70<span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">test</span><span class="special">/</span><span class="identifier">included</span><span class="special">/</span><span class="identifier">unit_test</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 71 72<span class="identifier">BOOST_AUTO_TEST_CASE</span><span class="special">(</span> <span class="identifier">test_pointers</span> <span class="special">)</span> 73<span class="special">{</span> 74 <span class="keyword">float</span> <span class="identifier">a</span><span class="special">(</span><span class="number">0.5f</span><span class="special">),</span> <span class="identifier">b</span><span class="special">(</span><span class="number">0.5f</span><span class="special">);</span> 75 <span class="keyword">const</span> <span class="keyword">float</span><span class="special">*</span> <span class="identifier">pa</span> <span class="special">=</span> <span class="special">&</span><span class="identifier">a</span><span class="special">,</span> <span class="special">*</span><span class="identifier">pb</span> <span class="special">=</span> <span class="special">&</span><span class="identifier">b</span><span class="special">;</span> 76 <span class="identifier">BOOST_TEST</span><span class="special">(</span><span class="identifier">a</span> <span class="special">==</span> <span class="identifier">b</span><span class="special">);</span> 77 <span class="identifier">BOOST_TEST</span><span class="special">(</span><span class="identifier">pa</span> <span class="special">==</span> <span class="identifier">pb</span><span class="special">);</span> 78<span class="special">}</span> 79 80<span class="identifier">BOOST_AUTO_TEST_CASE</span><span class="special">(</span> <span class="identifier">test_strings</span> <span class="special">)</span> 81<span class="special">{</span> 82 <span class="keyword">const</span> <span class="keyword">char</span><span class="special">*</span> <span class="identifier">a</span> <span class="special">=</span> <span class="string">"test1"</span><span class="special">;</span> 83 <span class="keyword">const</span> <span class="keyword">char</span><span class="special">*</span> <span class="identifier">b</span> <span class="special">=</span> <span class="string">"test2"</span><span class="special">;</span> 84 <span class="keyword">const</span> <span class="keyword">char</span><span class="special">*</span> <span class="identifier">c</span> <span class="special">=</span> <span class="string">"test1"</span><span class="special">;</span> 85 <span class="identifier">BOOST_TEST</span><span class="special">(</span><span class="identifier">a</span> <span class="special">==</span> <span class="identifier">b</span><span class="special">);</span> 86 <span class="identifier">BOOST_TEST</span><span class="special">(</span><span class="identifier">a</span> <span class="special">==</span> <span class="identifier">c</span><span class="special">);</span> 87 <span class="identifier">BOOST_TEST</span><span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span><span class="special">(</span><span class="string">"test1"</span><span class="special">)</span> <span class="special">==</span> <span class="identifier">b</span><span class="special">);</span> 88 <span class="identifier">BOOST_TEST</span><span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span><span class="special">(</span><span class="string">"test1"</span><span class="special">)</span> <span class="special"><</span> <span class="identifier">a</span><span class="special">,</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">test_tools</span><span class="special">::</span><span class="identifier">per_element</span><span class="special">());</span> 89 <span class="identifier">BOOST_TEST</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="identifier">boost</span><span class="special">::</span><span class="identifier">test_tools</span><span class="special">::</span><span class="identifier">lexicographic</span><span class="special">());</span> 90<span class="special">}</span> 91</pre> 92 </td></tr></tbody> 93</table></div> 94<div class="informaltable"><table class="table"> 95<colgroup><col></colgroup> 96<thead><tr><th> 97 <p> 98 Output 99 </p> 100 </th></tr></thead> 101<tbody><tr><td> 102<pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"><span class="special">></span> <span class="special">./</span><span class="identifier">boost_test_strings</span> 103<span class="identifier">Running</span> <span class="number">2</span> <span class="identifier">test</span> <span class="identifier">cases</span><span class="special">...</span> 104<span class="identifier">test</span><span class="special">.</span><span class="identifier">cpp</span><span class="special">:</span><span class="number">17</span><span class="special">:</span> <span class="identifier">error</span><span class="special">:</span> <span class="identifier">in</span> <span class="string">"test_pointers"</span><span class="special">:</span> <span class="identifier">check</span> <span class="identifier">pa</span> <span class="special">==</span> <span class="identifier">pb</span> <span class="identifier">has</span> <span class="identifier">failed</span> <span class="special">[</span><span class="number">0</span><span class="identifier">x7fff54f9dea4</span> <span class="special">!=</span> <span class="number">0</span><span class="identifier">x7fff54f9dea0</span><span class="special">]</span> 105<span class="identifier">test</span><span class="special">.</span><span class="identifier">cpp</span><span class="special">:</span><span class="number">25</span><span class="special">:</span> <span class="identifier">error</span><span class="special">:</span> <span class="identifier">in</span> <span class="string">"test_strings"</span><span class="special">:</span> <span class="identifier">check</span> <span class="identifier">a</span> <span class="special">==</span> <span class="identifier">b</span> <span class="identifier">has</span> <span class="identifier">failed</span> <span class="special">[</span><span class="identifier">test1</span> <span class="special">!=</span> <span class="identifier">test2</span><span class="special">]</span> 106<span class="identifier">test</span><span class="special">.</span><span class="identifier">cpp</span><span class="special">:</span><span class="number">27</span><span class="special">:</span> <span class="identifier">error</span><span class="special">:</span> <span class="identifier">in</span> <span class="string">"test_strings"</span><span class="special">:</span> <span class="identifier">check</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span><span class="special">(</span><span class="string">"test1"</span><span class="special">)</span> <span class="special">==</span> <span class="identifier">b</span> <span class="identifier">has</span> <span class="identifier">failed</span> <span class="special">[</span><span class="identifier">test1</span> <span class="special">!=</span> <span class="identifier">test2</span><span class="special">]</span> 107<span class="identifier">test</span><span class="special">.</span><span class="identifier">cpp</span><span class="special">:</span><span class="number">28</span><span class="special">:</span> <span class="identifier">error</span><span class="special">:</span> <span class="identifier">in</span> <span class="string">"test_strings"</span><span class="special">:</span> <span class="identifier">check</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span><span class="special">(</span><span class="string">"test1"</span><span class="special">)</span> <span class="special"><</span> <span class="identifier">a</span> <span class="identifier">has</span> <span class="identifier">failed</span> 108<span class="identifier">Mismatch</span> <span class="identifier">at</span> <span class="identifier">position</span> <span class="number">0</span><span class="special">:</span> <span class="char">'t'</span> <span class="special">>=</span> <span class="char">'t'</span><span class="special">.</span> 109<span class="identifier">Mismatch</span> <span class="identifier">at</span> <span class="identifier">position</span> <span class="number">1</span><span class="special">:</span> <span class="char">'e'</span> <span class="special">>=</span> <span class="char">'e'</span><span class="special">.</span> 110<span class="identifier">Mismatch</span> <span class="identifier">at</span> <span class="identifier">position</span> <span class="number">2</span><span class="special">:</span> <span class="char">'s'</span> <span class="special">>=</span> <span class="char">'s'</span><span class="special">.</span> 111<span class="identifier">Mismatch</span> <span class="identifier">at</span> <span class="identifier">position</span> <span class="number">3</span><span class="special">:</span> <span class="char">'t'</span> <span class="special">>=</span> <span class="char">'t'</span><span class="special">.</span> 112<span class="identifier">Mismatch</span> <span class="identifier">at</span> <span class="identifier">position</span> <span class="number">4</span><span class="special">:</span> <span class="char">'1'</span> <span class="special">>=</span> <span class="char">'1'</span><span class="special">.</span> 113<span class="identifier">test</span><span class="special">.</span><span class="identifier">cpp</span><span class="special">:</span><span class="number">29</span><span class="special">:</span> <span class="identifier">error</span><span class="special">:</span> <span class="identifier">in</span> <span class="string">"test_strings"</span><span class="special">:</span> <span class="identifier">check</span> <span class="identifier">b</span> <span class="special"><</span> <span class="identifier">a</span> <span class="identifier">has</span> <span class="identifier">failed</span> 114<span class="identifier">Failure</span> <span class="identifier">at</span> <span class="identifier">position</span> <span class="number">4</span><span class="special">:</span> <span class="char">'2'</span> <span class="special">>=</span> <span class="char">'1'</span><span class="special">.</span> 115 116<span class="special">***</span> <span class="number">5</span> <span class="identifier">failures</span> <span class="identifier">are</span> <span class="identifier">detected</span> <span class="identifier">in</span> <span class="identifier">the</span> <span class="identifier">test</span> <span class="identifier">module</span> <span class="string">"boost_test_strings"</span> 117</pre> 118 </td></tr></tbody> 119</table></div> 120<div class="note"><table border="0" summary="Note"> 121<tr> 122<td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../../../../../../../doc/src/images/note.png"></td> 123<th align="left">Note</th> 124</tr> 125<tr><td align="left" valign="top"><p> 126 <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">string_view</span></code> support added in Boost.Test 127 <a class="link" href="../../change_log.html#ref_CHANGE_LOG_3_12">Boost 1.72</a>. 128 </p></td></tr> 129</table></div> 130</div> 131<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 132<td align="left"></td> 133<td align="right"><div class="copyright-footer">Copyright © 2001-2020 Boost.Test contributors<p> 134 Distributed under the Boost Software License, Version 1.0. (See accompanying 135 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>) 136 </p> 137</div></td> 138</tr></table> 139<hr> 140<div class="spirit-nav"> 141<a accesskey="p" href="floating_point/floating_points_comparison_theory.html"><img src="../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../extended_comparison.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="collections.html"><img src="../../../../../../../doc/src/images/next.png" alt="Next"></a> 142</div> 143</body> 144</html> 145
