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| <a name="boost_regex.unicode"></a><a class="link" href="unicode.html" title="Unicode and Boost.Regex"> Unicode and Boost.Regex</a> |
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| <p> |
| There are two ways to use Boost.Regex with Unicode strings: |
| </p> |
| <a name="boost_regex.unicode.rely_on_wchar_t"></a><h5> |
| <a name="id905477"></a> |
| <a class="link" href="unicode.html#boost_regex.unicode.rely_on_wchar_t">Rely on wchar_t</a> |
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| <p> |
| If your platform's <code class="computeroutput"><span class="keyword">wchar_t</span></code> type |
| can hold Unicode strings, and your platform's C/C++ runtime correctly handles |
| wide character constants (when passed to <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">iswspace</span></code> |
| <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> |
| to process Unicode. However, there are several disadvantages to this approach: |
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| <div class="itemizedlist"><ul type="disc"> |
| <li> |
| It's not portable: there's no guarantee on the width of <code class="computeroutput"><span class="keyword">wchar_t</span></code>, |
| or even whether the runtime treats wide characters as Unicode at all, most |
| Windows compilers do so, but many Unix systems do not. |
| </li> |
| <li> |
| 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> |
| etc. |
| </li> |
| <li> |
| You can only search strings that are encoded as sequences of wide characters, |
| it is not possible to search UTF-8, or even UTF-16 on many platforms. |
| </li> |
| </ul></div> |
| <a name="boost_regex.unicode.use_a_unicode_aware_regular_expression_type_"></a><h5> |
| <a name="id905605"></a> |
| <a class="link" href="unicode.html#boost_regex.unicode.use_a_unicode_aware_regular_expression_type_">Use |
| a Unicode Aware Regular Expression Type.</a> |
| </h5> |
| <p> |
| If you have the <a href="http://www.ibm.com/software/globalization/icu/" target="_top">ICU |
| library</a>, then Boost.Regex can be <a class="link" href="install.html#boost_regex.install.building_with_unicode_and_icu_support">configured |
| to make use of it</a>, and provide a distinct regular expression type (boost::u32regex), |
| that supports both Unicode specific character properties, and the searching |
| 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 |
| string class support</a>. |
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| <td align="right"><div class="copyright-footer">Copyright © 1998 -2010 John Maddock<p> |
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