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  26 <div class="titlepage"><div><div><h2 class="title" style="clear: both">
  27 <a name="boost_regex.unicode"></a><a class="link" href="unicode.html" title="Unicode and Boost.Regex">Unicode and Boost.Regex</a>
  28 </h2></div></div></div>
  29 <p>
  30       There are two ways to use Boost.Regex with Unicode strings:
  31     </p>
  32 <h5>
  33 <a name="boost_regex.unicode.h0"></a>
  34       <span class="phrase"><a name="boost_regex.unicode.rely_on_wchar_t"></a></span><a class="link" href="unicode.html#boost_regex.unicode.rely_on_wchar_t">Rely
  35       on wchar_t</a>
  36     </h5>
  37 <p>
  38       If your platform's <code class="computeroutput"><span class="keyword">wchar_t</span></code> type
  39       can hold Unicode strings, and your platform's C/C++ runtime correctly handles
  40       wide character constants (when passed to <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">iswspace</span></code>
  41       <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>
  42       to process Unicode. However, there are several disadvantages to this approach:
  43     </p>
  44 <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
  45 <li class="listitem">
  46           It's not portable: there's no guarantee on the width of <code class="computeroutput"><span class="keyword">wchar_t</span></code>,
  47           or even whether the runtime treats wide characters as Unicode at all, most
  48           Windows compilers do so, but many Unix systems do not.
  49         </li>
  50 <li class="listitem">
  51           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>, <code class="computeroutput"><span class="special">[[:</span><span class="identifier">Po</span><span class="special">:]]</span></code>
  52           etc.
  53         </li>
  54 <li class="listitem">
  55           You can only search strings that are encoded as sequences of wide characters,
  56           it is not possible to search UTF-8, or even UTF-16 on many platforms.
  57         </li>
  58 </ul></div>
  59 <h5>
  60 <a name="boost_regex.unicode.h1"></a>
  61       <span class="phrase"><a name="boost_regex.unicode.use_a_unicode_aware_regular_expr"></a></span><a class="link" href="unicode.html#boost_regex.unicode.use_a_unicode_aware_regular_expr">Use
  62       a Unicode Aware Regular Expression Type.</a>
  63     </h5>
  64 <p>
  65       If you have the <a href="http://www.ibm.com/software/globalization/icu/" target="_top">ICU
  66       library</a>, then Boost.Regex can be <a class="link" href="install.html#boost_regex.install.building_with_unicode_and_icu_su">configured
  67       to make use of it</a>, and provide a distinct regular expression type (boost::u32regex),
  68       that supports both Unicode specific character properties, and the searching
  69       of text that is encoded in either UTF-8, UTF-16, or UTF-32. See: <a class="link" href="ref/non_std_strings/icu.html" title="Working With Unicode and ICU String Types">ICU
  70       string class support</a>.
  71     </p>
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  75 <td align="right"><div class="copyright-footer">Copyright &#169; 1998-2013 John Maddock<p>
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  77         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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