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<div class="titlepage"><div><div><h2 class="title" style="clear: both">
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<a name="boost_regex.unicode"></a><a href="unicode.html" title="Unicode and Boost.Regex"> Unicode and Boost.Regex</a>
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</h2></div></div></div>
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<p>
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There are two ways to use Boost.Regex with Unicode strings:
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</p>
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<a name="boost_regex.unicode.rely_on_wchar_t"></a><h5>
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<a name="id502607"></a>
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<a href="unicode.html#boost_regex.unicode.rely_on_wchar_t">Rely on wchar_t</a>
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</h5>
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<p>
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If your platform's <code class="computeroutput"><span class="keyword">wchar_t</span></code> type
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can hold Unicode strings, and your platform's C/C++ runtime correctly handles
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wide character constants (when passed to <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">iswspace</span></code>
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<code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">iswlower</span></code> etc), then you can use <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">wregex</span></code>
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to process Unicode. However, there are several disadvantages to this approach:
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</p>
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<div class="itemizedlist"><ul type="disc">
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<li>
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It's not portable: there's no guarantee on the width of <code class="computeroutput"><span class="keyword">wchar_t</span></code>,
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or even whether the runtime treats wide characters as Unicode at all, most
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Windows compilers do so, but many Unix systems do not.
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</li>
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<li>
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There's no support for Unicode-specific character classes: <code class="computeroutput"><span class="special">[[:</span><span class="identifier">Nd</span><span class="special">:]]</span></code>,
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<code class="computeroutput"><span class="special">[[:</span><span class="identifier">Po</span><span class="special">:]]</span></code> etc.
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</li>
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<li>
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You can only search strings that are encoded as sequences of wide characters,
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it is not possible to search UTF-8, or even UTF-16 on many platforms.
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</li>
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</ul></div>
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<a name="boost_regex.unicode.use_a_unicode_aware_regular_expression_type_"></a><h5>
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<a name="id502791"></a>
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<a href="unicode.html#boost_regex.unicode.use_a_unicode_aware_regular_expression_type_">Use
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a Unicode Aware Regular Expression Type.</a>
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</h5>
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<p>
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If you have the <a href="http://www.ibm.com/software/globalization/icu/" target="_top">ICU
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library</a>, then Boost.Regex can be <a href="install.html#boost_regex.install.building_with_unicode_and_icu_support">configured
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to make use of it</a>, and provide a distinct regular expression type (boost::u32regex),
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that supports both Unicode specific character properties, and the searching
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of text that is encoded in either UTF-8, UTF-16, or UTF-32. See: <a href="ref/non_std_strings/icu.html" title="Working With Unicode and ICU String Types">ICU
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string class support</a>.
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</p>
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<td align="left"></td>
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<td align="right"><div class="copyright-footer">Copyright <20> 1998 -2007 John Maddock<p>
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Distributed under the Boost Software License, Version 1.0. (See accompanying
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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>)
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