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<h1 align="center">Boost.Regex</h1>
<h2 align="center">Localisation</h2>
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<p>Boost.regex&nbsp;provides extensive support for run-time
localization, the localization model used can be split into two
parts: front-end and back-end.</p>
<p>Front-end localization deals with everything which the user sees
- error messages, and the regular expression syntax itself. For
example a French application could change [[:word:]] to [[:mot:]]
and \w to \m. Modifying the front end locale requires active
support from the developer, by providing the library with a message
catalogue to load, containing the localized strings. Front-end
locale is affected by the LC_MESSAGES category only.</p>
<p>Back-end localization deals with everything that occurs after
the expression has been parsed - in other words everything that the
user does not see or interact with directly. It deals with case
conversion, collation, and character class membership. The back-end
locale does not require any intervention from the developer - the
library will acquire all the information it requires for the
current locale from the underlying operating system / run time
library. This means that if the program user does not interact with
regular expressions directly - for example if the expressions are
embedded in your C++ code - then no explicit localization is
required, as the library will take care of everything for you. For
example embedding the expression [[:word:]]+ in your code will
always match a whole word, if the program is run on a machine with,
for example, a Greek locale, then it will still match a whole word,
but in Greek characters rather than Latin ones. The back-end locale
is affected by the LC_TYPE and LC_COLLATE categories.</p>
<p>There are three separate localization mechanisms supported by
boost.regex:</p>
<h3>Win32 localization model.</h3>
<p>This is the default model when the library is compiled under
Win32, and is encapsulated by the traits class w32_regex_traits.
When this model is in effect there is a single global locale as
defined by the user's control panel settings, and returned by
GetUserDefaultLCID. All the settings used by boost.regex are
acquired directly from the operating system bypassing the C run
time library. Front-end localization requires a resource dll,
containing a string table with the user-defined strings. The traits
class exports the function:</p>
<p>static std::string set_message_catalogue(const std::string&amp;
s);</p>
<p>which needs to be called with a string identifying the name of
the resource dll, <i>before</i> your code compiles any regular
expressions (but not necessarily before you construct any <i>
basic_regex</i> instances):</p>
<p>
boost::w32_regex_traits&lt;char&gt;::set_message_catalogue("mydll.dll");</p>
<p>Note that this API sets the dll name for <i>both</i> the narrow
and wide character specializations of w32_regex_traits.</p>
<p>This model does not currently support thread specific locales
(via SetThreadLocale under Windows NT), the library provides full
Unicode support under NT, under Windows 9x the library degrades
gracefully - characters 0 to 255 are supported, the remainder are
treated as "unknown" graphic characters.</p>
<h3>C localization model.</h3>
<p>This is the default model when the library is compiled under an
operating system other than Win32, and is encapsulated by the
traits class <i>c_regex_traits</i>, Win32 users can force this
model to take effect by defining the pre-processor symbol
BOOST_REGEX_USE_C_LOCALE. When this model is in effect there is a
single global locale, as set by <i>setlocale</i>. All settings are
acquired from your run time library, consequently Unicode support
is dependent upon your run time library implementation. Front end
localization requires a POSIX message catalogue. The traits class
exports the function:</p>
<p>static std::string set_message_catalogue(const std::string&amp;
s);</p>
<p>which needs to be called with a string identifying the name of
the message catalogue, <i>before</i> your code compiles any regular
expressions (but not necessarily before you construct any <i>
basic_regex</i> instances):</p>
<p>
boost::c_regex_traits&lt;char&gt;::set_message_catalogue("mycatalogue");</p>
<p>Note that this API sets the dll name for <i>both</i> the narrow
and wide character specializations of c_regex_traits. If your run
time library does not support POSIX message catalogues, then you
can either provide your own implementation of &lt;nl_types.h&gt; or
define BOOST_RE_NO_CAT to disable front-end localization via
message catalogues.</p>
<p>Note that calling <i>setlocale</i> invalidates all compiled
regular expressions, calling <tt>setlocale(LC_ALL, "C")</tt> will
make this library behave equivalent to most traditional regular
expression libraries including version 1 of this library.</p>
<h3>C++ localization model.</h3>
<p>This model is only in effect if the library is built with the
pre-processor symbol BOOST_REGEX_USE_CPP_LOCALE defined. When this
model is in effect each instance of basic_regex&lt;&gt; has its own
instance of std::locale, class basic_regex&lt;&gt; also has a
member function <i>imbue</i> which allows the locale for the
expression to be set on a per-instance basis. Front end
localization requires a POSIX message catalogue, which will be
loaded via the std::messages facet of the expression's locale, the
traits class exports the symbol:</p>
<p>static std::string set_message_catalogue(const std::string&amp;
s);</p>
<p>which needs to be called with a string identifying the name of
the message catalogue, <i>before</i> your code compiles any regular
expressions (but not necessarily before you construct any <i>
basic_regex</i> instances):</p>
<p>
boost::cpp_regex_traits&lt;char&gt;::set_message_catalogue("mycatalogue");</p>
<p>Note that calling basic_regex&lt;&gt;::imbue will invalidate any
expression currently compiled in that instance of
basic_regex&lt;&gt;. This model is the one which closest fits the
ethos of the C++ standard library, however it is the model which
will produce the slowest code, and which is the least well
supported by current standard library implementations, for example
I have yet to find an implementation of std::locale which supports
either message catalogues, or locales other than "C" or
"POSIX".</p>
<p>Finally note that if you build the library with a non-default
localization model, then the appropriate pre-processor symbol
(BOOST_REGEX_USE_C_LOCALE or BOOST_REGEX_USE_CPP_LOCALE) must be
defined both when you build the support library, and when you
include &lt;boost/regex.hpp&gt; or &lt;boost/cregex.hpp&gt; in your
code. The best way to ensure this is to add the #define to
&lt;boost/regex/user.hpp&gt;.</p>
<h3>Providing a message catalogue:</h3>
<p>In order to localize the front end of the library, you need to
provide the library with the appropriate message strings contained
either in a resource dll's string table (Win32 model), or a POSIX
message catalogue (C or C++ models). In the latter case the
messages must appear in message set zero of the catalogue. The
messages and their id's are as follows:<br>
&nbsp;</p>
<p></p>
<table id="Table2" cellspacing="0" cellpadding="6" width="624"
border="0">
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="21%">Message id</td>
<td valign="top" width="32%">Meaning</td>
<td valign="top" width="29%">Default value</td>
<td valign="top" width="9%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="21%">101</td>
<td valign="top" width="32%">The character used to start a
sub-expression.</td>
<td valign="top" width="29%">"("</td>
<td valign="top" width="9%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="21%">102</td>
<td valign="top" width="32%">The character used to end a
sub-expression declaration.</td>
<td valign="top" width="29%">")"</td>
<td valign="top" width="9%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="21%">103</td>
<td valign="top" width="32%">The character used to denote an end of
line assertion.</td>
<td valign="top" width="29%">"$"</td>
<td valign="top" width="9%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="21%">104</td>
<td valign="top" width="32%">The character used to denote the start
of line assertion.</td>
<td valign="top" width="29%">"^"</td>
<td valign="top" width="9%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="21%">105</td>
<td valign="top" width="32%">The character used to denote the
"match any character expression".</td>
<td valign="top" width="29%">"."</td>
<td valign="top" width="9%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="21%">106</td>
<td valign="top" width="32%">The match zero or more times
repetition operator.</td>
<td valign="top" width="29%">"*"</td>
<td valign="top" width="9%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="21%">107</td>
<td valign="top" width="32%">The match one or more repetition
operator.</td>
<td valign="top" width="29%">"+"</td>
<td valign="top" width="9%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="21%">108</td>
<td valign="top" width="32%">The match zero or one repetition
operator.</td>
<td valign="top" width="29%">"?"</td>
<td valign="top" width="9%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="21%">109</td>
<td valign="top" width="32%">The character set opening
character.</td>
<td valign="top" width="29%">"["</td>
<td valign="top" width="9%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="21%">110</td>
<td valign="top" width="32%">The character set closing
character.</td>
<td valign="top" width="29%">"]"</td>
<td valign="top" width="9%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="21%">111</td>
<td valign="top" width="32%">The alternation operator.</td>
<td valign="top" width="29%">"|"</td>
<td valign="top" width="9%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="21%">112</td>
<td valign="top" width="32%">The escape character.</td>
<td valign="top" width="29%">"\\"</td>
<td valign="top" width="9%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="21%">113</td>
<td valign="top" width="32%">The hash character (not currently
used).</td>
<td valign="top" width="29%">"#"</td>
<td valign="top" width="9%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="21%">114</td>
<td valign="top" width="32%">The range operator.</td>
<td valign="top" width="29%">"-"</td>
<td valign="top" width="9%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="21%">115</td>
<td valign="top" width="32%">The repetition operator opening
character.</td>
<td valign="top" width="29%">"{"</td>
<td valign="top" width="9%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="21%">116</td>
<td valign="top" width="32%">The repetition operator closing
character.</td>
<td valign="top" width="29%">"}"</td>
<td valign="top" width="9%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="21%">117</td>
<td valign="top" width="32%">The digit characters.</td>
<td valign="top" width="29%">"0123456789"</td>
<td valign="top" width="9%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="21%">118</td>
<td valign="top" width="32%">The character which when preceded by
an escape character represents the word boundary assertion.</td>
<td valign="top" width="29%">"b"</td>
<td valign="top" width="9%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="21%">119</td>
<td valign="top" width="32%">The character which when preceded by
an escape character represents the non-word boundary
assertion.</td>
<td valign="top" width="29%">"B"</td>
<td valign="top" width="9%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="21%">120</td>
<td valign="top" width="32%">The character which when preceded by
an escape character represents the word-start boundary
assertion.</td>
<td valign="top" width="29%">"&lt;"</td>
<td valign="top" width="9%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="21%">121</td>
<td valign="top" width="32%">The character which when preceded by
an escape character represents the word-end boundary
assertion.</td>
<td valign="top" width="29%">"&gt;"</td>
<td valign="top" width="9%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="21%">122</td>
<td valign="top" width="32%">The character which when preceded by
an escape character represents any word character.</td>
<td valign="top" width="29%">"w"</td>
<td valign="top" width="9%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="21%">123</td>
<td valign="top" width="32%">The character which when preceded by
an escape character represents a non-word character.</td>
<td valign="top" width="29%">"W"</td>
<td valign="top" width="9%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="21%">124</td>
<td valign="top" width="32%">The character which when preceded by
an escape character represents a start of buffer assertion.</td>
<td valign="top" width="29%">"`A"</td>
<td valign="top" width="9%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="21%">125</td>
<td valign="top" width="32%">The character which when preceded by
an escape character represents an end of buffer assertion.</td>
<td valign="top" width="29%">"'z"</td>
<td valign="top" width="9%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="21%">126</td>
<td valign="top" width="32%">The newline character.</td>
<td valign="top" width="29%">"\n"</td>
<td valign="top" width="9%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="21%">127</td>
<td valign="top" width="32%">The comma separator.</td>
<td valign="top" width="29%">","</td>
<td valign="top" width="9%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="21%">128</td>
<td valign="top" width="32%">The character which when preceded by
an escape character represents the bell character.</td>
<td valign="top" width="29%">"a"</td>
<td valign="top" width="9%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="21%">129</td>
<td valign="top" width="32%">The character which when preceded by
an escape character represents the form feed character.</td>
<td valign="top" width="29%">"f"</td>
<td valign="top" width="9%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="21%">130</td>
<td valign="top" width="32%">The character which when preceded by
an escape character represents the newline character.</td>
<td valign="top" width="29%">"n"</td>
<td valign="top" width="9%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="21%">131</td>
<td valign="top" width="32%">The character which when preceded by
an escape character represents the carriage return character.</td>
<td valign="top" width="29%">"r"</td>
<td valign="top" width="9%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="21%">132</td>
<td valign="top" width="32%">The character which when preceded by
an escape character represents the tab character.</td>
<td valign="top" width="29%">"t"</td>
<td valign="top" width="9%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="21%">133</td>
<td valign="top" width="32%">The character which when preceded by
an escape character represents the vertical tab character.</td>
<td valign="top" width="29%">"v"</td>
<td valign="top" width="9%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="21%">134</td>
<td valign="top" width="32%">The character which when preceded by
an escape character represents the start of a hexadecimal character
constant.</td>
<td valign="top" width="29%">"x"</td>
<td valign="top" width="9%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="21%">135</td>
<td valign="top" width="32%">The character which when preceded by
an escape character represents the start of an ASCII escape
character.</td>
<td valign="top" width="29%">"c"</td>
<td valign="top" width="9%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="21%">136</td>
<td valign="top" width="32%">The colon character.</td>
<td valign="top" width="29%">":"</td>
<td valign="top" width="9%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="21%">137</td>
<td valign="top" width="32%">The equals character.</td>
<td valign="top" width="29%">"="</td>
<td valign="top" width="9%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="21%">138</td>
<td valign="top" width="32%">The character which when preceded by
an escape character represents the ASCII escape character.</td>
<td valign="top" width="29%">"e"</td>
<td valign="top" width="9%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="21%">139</td>
<td valign="top" width="32%">The character which when preceded by
an escape character represents any lower case character.</td>
<td valign="top" width="29%">"l"</td>
<td valign="top" width="9%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="21%">140</td>
<td valign="top" width="32%">The character which when preceded by
an escape character represents any non-lower case character.</td>
<td valign="top" width="29%">"L"</td>
<td valign="top" width="9%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="21%">141</td>
<td valign="top" width="32%">The character which when preceded by
an escape character represents any upper case character.</td>
<td valign="top" width="29%">"u"</td>
<td valign="top" width="9%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="21%">142</td>
<td valign="top" width="32%">The character which when preceded by
an escape character represents any non-upper case character.</td>
<td valign="top" width="29%">"U"</td>
<td valign="top" width="9%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="21%">143</td>
<td valign="top" width="32%">The character which when preceded by
an escape character represents any space character.</td>
<td valign="top" width="29%">"s"</td>
<td valign="top" width="9%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="21%">144</td>
<td valign="top" width="32%">The character which when preceded by
an escape character represents any non-space character.</td>
<td valign="top" width="29%">"S"</td>
<td valign="top" width="9%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="21%">145</td>
<td valign="top" width="32%">The character which when preceded by
an escape character represents any digit character.</td>
<td valign="top" width="29%">"d"</td>
<td valign="top" width="9%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="21%">146</td>
<td valign="top" width="32%">The character which when preceded by
an escape character represents any non-digit character.</td>
<td valign="top" width="29%">"D"</td>
<td valign="top" width="9%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="21%">147</td>
<td valign="top" width="32%">The character which when preceded by
an escape character represents the end quote operator.</td>
<td valign="top" width="29%">"E"</td>
<td valign="top" width="9%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="21%">148</td>
<td valign="top" width="32%">The character which when preceded by
an escape character represents the start quote operator.</td>
<td valign="top" width="29%">"Q"</td>
<td valign="top" width="9%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="21%">149</td>
<td valign="top" width="32%">The character which when preceded by
an escape character represents a Unicode combining character
sequence.</td>
<td valign="top" width="29%">"X"</td>
<td valign="top" width="9%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="21%">150</td>
<td valign="top" width="32%">The character which when preceded by
an escape character represents any single character.</td>
<td valign="top" width="29%">"C"</td>
<td valign="top" width="9%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="21%">151</td>
<td valign="top" width="32%">The character which when preceded by
an escape character represents end of buffer operator.</td>
<td valign="top" width="29%">"Z"</td>
<td valign="top" width="9%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="21%">152</td>
<td valign="top" width="32%">The character which when preceded by
an escape character represents the continuation assertion.</td>
<td valign="top" width="29%">"G"</td>
<td valign="top" width="9%">&nbsp;</td>
</tr>
<tr>
<td>&nbsp;</td>
<td>153</td>
<td>The character which when preceeded by (? indicates a zero width
negated forward lookahead assert.</td>
<td>!</td>
<td>&nbsp;</td>
</tr>
</table>
<br>
<br>
<p>Custom error messages are loaded as follows:&nbsp;</p>
<p></p>
<table id="Table3" cellspacing="0" cellpadding="7" width="624"
border="0">
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="22%">Message ID</td>
<td valign="top" width="32%">Error message ID</td>
<td valign="top" width="31%">Default string</td>
<td valign="top" width="7%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="22%">201</td>
<td valign="top" width="32%">REG_NOMATCH</td>
<td valign="top" width="31%">"No match"</td>
<td valign="top" width="7%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="22%">202</td>
<td valign="top" width="32%">REG_BADPAT</td>
<td valign="top" width="31%">"Invalid regular expression"</td>
<td valign="top" width="7%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="22%">203</td>
<td valign="top" width="32%">REG_ECOLLATE</td>
<td valign="top" width="31%">"Invalid collation character"</td>
<td valign="top" width="7%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="22%">204</td>
<td valign="top" width="32%">REG_ECTYPE</td>
<td valign="top" width="31%">"Invalid character class name"</td>
<td valign="top" width="7%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="22%">205</td>
<td valign="top" width="32%">REG_EESCAPE</td>
<td valign="top" width="31%">"Trailing backslash"</td>
<td valign="top" width="7%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="22%">206</td>
<td valign="top" width="32%">REG_ESUBREG</td>
<td valign="top" width="31%">"Invalid back reference"</td>
<td valign="top" width="7%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="22%">207</td>
<td valign="top" width="32%">REG_EBRACK</td>
<td valign="top" width="31%">"Unmatched [ or [^"</td>
<td valign="top" width="7%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="22%">208</td>
<td valign="top" width="32%">REG_EPAREN</td>
<td valign="top" width="31%">"Unmatched ( or \\("</td>
<td valign="top" width="7%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="22%">209</td>
<td valign="top" width="32%">REG_EBRACE</td>
<td valign="top" width="31%">"Unmatched \\{"</td>
<td valign="top" width="7%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="22%">210</td>
<td valign="top" width="32%">REG_BADBR</td>
<td valign="top" width="31%">"Invalid content of \\{\\}"</td>
<td valign="top" width="7%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="22%">211</td>
<td valign="top" width="32%">REG_ERANGE</td>
<td valign="top" width="31%">"Invalid range end"</td>
<td valign="top" width="7%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="22%">212</td>
<td valign="top" width="32%">REG_ESPACE</td>
<td valign="top" width="31%">"Memory exhausted"</td>
<td valign="top" width="7%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="22%">213</td>
<td valign="top" width="32%">REG_BADRPT</td>
<td valign="top" width="31%">"Invalid preceding regular
expression"</td>
<td valign="top" width="7%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="22%">214</td>
<td valign="top" width="32%">REG_EEND</td>
<td valign="top" width="31%">"Premature end of regular
expression"</td>
<td valign="top" width="7%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="22%">215</td>
<td valign="top" width="32%">REG_ESIZE</td>
<td valign="top" width="31%">"Regular expression too big"</td>
<td valign="top" width="7%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="22%">216</td>
<td valign="top" width="32%">REG_ERPAREN</td>
<td valign="top" width="31%">"Unmatched ) or \\)"</td>
<td valign="top" width="7%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="22%">217</td>
<td valign="top" width="32%">REG_EMPTY</td>
<td valign="top" width="31%">"Empty expression"</td>
<td valign="top" width="7%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="22%">218</td>
<td valign="top" width="32%">REG_E_UNKNOWN</td>
<td valign="top" width="31%">"Unknown error"</td>
<td valign="top" width="7%">&nbsp;</td>
</tr>
</table>
<br>
<br>
<p>Custom character class names are loaded as followed:&nbsp;</p>
<p></p>
<table id="Table4" cellspacing="0" cellpadding="7" width="624"
border="0">
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="22%">Message ID</td>
<td valign="top" width="32%">Description</td>
<td valign="top" width="31%">Equivalent default class name</td>
<td valign="top" width="7%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="22%">300</td>
<td valign="top" width="32%">The character class name for
alphanumeric characters.</td>
<td valign="top" width="31%">"alnum"</td>
<td valign="top" width="7%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="22%">301</td>
<td valign="top" width="32%">The character class name for
alphabetic characters.</td>
<td valign="top" width="31%">"alpha"</td>
<td valign="top" width="7%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="22%">302</td>
<td valign="top" width="32%">The character class name for control
characters.</td>
<td valign="top" width="31%">"cntrl"</td>
<td valign="top" width="7%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="22%">303</td>
<td valign="top" width="32%">The character class name for digit
characters.</td>
<td valign="top" width="31%">"digit"</td>
<td valign="top" width="7%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="22%">304</td>
<td valign="top" width="32%">The character class name for graphics
characters.</td>
<td valign="top" width="31%">"graph"</td>
<td valign="top" width="7%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="22%">305</td>
<td valign="top" width="32%">The character class name for lower
case characters.</td>
<td valign="top" width="31%">"lower"</td>
<td valign="top" width="7%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="22%">306</td>
<td valign="top" width="32%">The character class name for printable
characters.</td>
<td valign="top" width="31%">"print"</td>
<td valign="top" width="7%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="22%">307</td>
<td valign="top" width="32%">The character class name for
punctuation characters.</td>
<td valign="top" width="31%">"punct"</td>
<td valign="top" width="7%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="22%">308</td>
<td valign="top" width="32%">The character class name for space
characters.</td>
<td valign="top" width="31%">"space"</td>
<td valign="top" width="7%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="22%">309</td>
<td valign="top" width="32%">The character class name for upper
case characters.</td>
<td valign="top" width="31%">"upper"</td>
<td valign="top" width="7%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="22%">310</td>
<td valign="top" width="32%">The character class name for
hexadecimal characters.</td>
<td valign="top" width="31%">"xdigit"</td>
<td valign="top" width="7%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="22%">311</td>
<td valign="top" width="32%">The character class name for blank
characters.</td>
<td valign="top" width="31%">"blank"</td>
<td valign="top" width="7%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="22%">312</td>
<td valign="top" width="32%">The character class name for word
characters.</td>
<td valign="top" width="31%">"word"</td>
<td valign="top" width="7%">&nbsp;</td>
</tr>
<tr>
<td valign="top" width="8%">&nbsp;</td>
<td valign="top" width="22%">313</td>
<td valign="top" width="32%">The character class name for Unicode
characters.</td>
<td valign="top" width="31%">"unicode"</td>
<td valign="top" width="7%">&nbsp;</td>
</tr>
</table>
<br>
<br>
<p>Finally, custom collating element names are loaded starting from
message id 400, and terminating when the first load thereafter
fails. Each message looks something like: "tagname string" where
<i>tagname</i> is the name used inside [[.tagname.]] and <i>
string</i> is the actual text of the collating element. Note that
the value of collating element [[.zero.]] is used for the
conversion of strings to numbers - if you replace this with another
value then that will be used for string parsing - for example use
the Unicode character 0x0660 for [[.zero.]] if you want to use
Unicode Arabic-Indic digits in your regular expressions in place of
Latin digits.</p>
<p>Note that the POSIX defined names for character classes and
collating elements are always available - even if custom names are
defined, in contrast, custom error messages, and custom syntax
messages replace the default ones.</p>
<p></p>
<hr>
<p>Revised
<!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan -->
17 May 2003
<!--webbot bot="Timestamp" endspan i-checksum="39359" --></p>
<p><i>&copy; Copyright <a href="mailto:jm@regex.fsnet.co.uk">John
Maddock</a>&nbsp;1998-
<!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%Y" startspan -->
2003
<!--webbot bot="Timestamp" endspan i-checksum="39359" --></i></p>
<p align="left"><i>Permission to use, copy, modify, distribute and
sell this software and its documentation for any purpose is hereby
granted without fee, provided that the above copyright notice
appear in all copies and that both that copyright notice and this
permission notice appear in supporting documentation. Dr John
Maddock makes no representations about the suitability of this
software for any purpose. It is provided "as is" without express or
implied warranty.</i></p>
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