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  26 <div class="titlepage"><div><div><h3 class="title">
  27 <a name="boost_regex.background_information.locale"></a><a class="link" href="locale.html" title="Localization">Localization</a>
  28 </h3></div></div></div>
  29 <p>
  30         Boost.Regex provides extensive support for run-time localization, the localization
  31         model used can be split into two parts: front-end and back-end.
  32       </p>
  33 <p>
  34         Front-end localization deals with everything which the user sees - error
  35         messages, and the regular expression syntax itself. For example a French
  36         application could change [[:word:]] to [[:mot:]] and \w to \m. Modifying
  37         the front end locale requires active support from the developer, by providing
  38         the library with a message catalogue to load, containing the localized strings.
  39         Front-end locale is affected by the LC_MESSAGES category only.
  40       </p>
  41 <p>
  42         Back-end localization deals with everything that occurs after the expression
  43         has been parsed - in other words everything that the user does not see or
  44         interact with directly. It deals with case conversion, collation, and character
  45         class membership. The back-end locale does not require any intervention from
  46         the developer - the library will acquire all the information it requires
  47         for the current locale from the underlying operating system / run time library.
  48         This means that if the program user does not interact with regular expressions
  49         directly - for example if the expressions are embedded in your C++ code -
  50         then no explicit localization is required, as the library will take care
  51         of everything for you. For example embedding the expression [[:word:]]+ in
  52         your code will always match a whole word, if the program is run on a machine
  53         with, for example, a Greek locale, then it will still match a whole word,
  54         but in Greek characters rather than Latin ones. The back-end locale is affected
  55         by the LC_TYPE and LC_COLLATE categories.
  56       </p>
  57 <p>
  58         There are three separate localization mechanisms supported by Boost.Regex:
  59       </p>
  60 <h5>
  61 <a name="boost_regex.background_information.locale.h0"></a>
  62         <span><a name="boost_regex.background_information.locale.win32_localization_model_"></a></span><a class="link" href="locale.html#boost_regex.background_information.locale.win32_localization_model_">Win32
  63         localization model.</a>
  64       </h5>
  65 <p>
  66         This is the default model when the library is compiled under Win32, and is
  67         encapsulated by the traits class <code class="computeroutput"><span class="identifier">w32_regex_traits</span></code>.
  68         When this model is in effect each <a class="link" href="../ref/basic_regex.html" title="basic_regex"><code class="computeroutput"><span class="identifier">basic_regex</span></code></a> object gets it's own
  69         LCID, by default this is the users default setting as returned by GetUserDefaultLCID,
  70         but you can call imbue on the <code class="computeroutput"><span class="identifier">basic_regex</span></code>
  71         object to set it's locale to some other LCID if you wish. All the settings
  72         used by Boost.Regex are acquired directly from the operating system bypassing
  73         the C run time library. Front-end localization requires a resource dll, containing
  74         a string table with the user-defined strings. The traits class exports the
  75         function:
  76       </p>
  77 <pre class="programlisting"><span class="keyword">static</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span> <span class="identifier">set_message_catalogue</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span><span class="special">&amp;</span> <span class="identifier">s</span><span class="special">);</span>
  78 </pre>
  79 <p>
  80         which needs to be called with a string identifying the name of the resource
  81         dll, before your code compiles any regular expressions (but not necessarily
  82         before you construct any <code class="computeroutput"><span class="identifier">basic_regex</span></code>
  83         instances):
  84       </p>
  85 <pre class="programlisting"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">w32_regex_traits</span><span class="special">&lt;</span><span class="keyword">char</span><span class="special">&gt;::</span><span class="identifier">set_message_catalogue</span><span class="special">(</span><span class="string">"mydll.dll"</span><span class="special">);</span>
  86 </pre>
  87 <p>
  88         The library provides full Unicode support under NT, under Windows 9x the
  89         library degrades gracefully - characters 0 to 255 are supported, the remainder
  90         are treated as "unknown" graphic characters.
  91       </p>
  92 <h5>
  93 <a name="boost_regex.background_information.locale.h1"></a>
  94         <span><a name="boost_regex.background_information.locale.c_localization_model_"></a></span><a class="link" href="locale.html#boost_regex.background_information.locale.c_localization_model_">C
  95         localization model.</a>
  96       </h5>
  97 <p>
  98         This model has been deprecated in favor of the C++ locale for all non-Windows
  99         compilers that support it. This locale is encapsulated by the traits class
 100         <code class="computeroutput"><span class="identifier">c_regex_traits</span></code>, Win32 users
 101         can force this model to take effect by defining the pre-processor symbol
 102         BOOST_REGEX_USE_C_LOCALE. When this model is in effect there is a single
 103         global locale, as set by <code class="computeroutput"><span class="identifier">setlocale</span></code>.
 104         All settings are acquired from your run time library, consequently Unicode
 105         support is dependent upon your run time library implementation.
 106       </p>
 107 <p>
 108         Front end localization is not supported.
 109       </p>
 110 <p>
 111         Note that calling setlocale invalidates all compiled regular expressions,
 112         calling <code class="computeroutput"><span class="identifier">setlocale</span><span class="special">(</span><span class="identifier">LC_ALL</span><span class="special">,</span> <span class="string">"C"</span><span class="special">)</span></code>
 113         will make this library behave equivalent to most traditional regular expression
 114         libraries including version 1 of this library.
 115       </p>
 116 <h5>
 117 <a name="boost_regex.background_information.locale.h2"></a>
 118         <span><a name="boost_regex.background_information.locale.c___localization_model_"></a></span><a class="link" href="locale.html#boost_regex.background_information.locale.c___localization_model_">C++
 119         localization model.</a>
 120       </h5>
 121 <p>
 122         This model is the default for non-Windows compilers.
 123       </p>
 124 <p>
 125         When this model is in effect each instance of <a class="link" href="../ref/basic_regex.html" title="basic_regex"><code class="computeroutput"><span class="identifier">basic_regex</span></code></a> has its own instance
 126         of <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">locale</span></code>, class <a class="link" href="../ref/basic_regex.html" title="basic_regex"><code class="computeroutput"><span class="identifier">basic_regex</span></code></a> also has a member function
 127         <code class="computeroutput"><span class="identifier">imbue</span></code> which allows the locale
 128         for the expression to be set on a per-instance basis. Front end localization
 129         requires a POSIX message catalogue, which will be loaded via the <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">messages</span></code>
 130         facet of the expression's locale, the traits class exports the symbol:
 131       </p>
 132 <pre class="programlisting"><span class="keyword">static</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span> <span class="identifier">set_message_catalogue</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span><span class="special">&amp;</span> <span class="identifier">s</span><span class="special">);</span>
 133 </pre>
 134 <p>
 135         which needs to be called with a string identifying the name of the message
 136         catalogue, before your code compiles any regular expressions (but not necessarily
 137         before you construct any basic_regex instances):
 138       </p>
 139 <pre class="programlisting"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">cpp_regex_traits</span><span class="special">&lt;</span><span class="keyword">char</span><span class="special">&gt;::</span><span class="identifier">set_message_catalogue</span><span class="special">(</span><span class="string">"mycatalogue"</span><span class="special">);</span>
 140 </pre>
 141 <p>
 142         Note that calling <code class="computeroutput"><span class="identifier">basic_regex</span><span class="special">&lt;&gt;::</span><span class="identifier">imbue</span></code>
 143         will invalidate any expression currently compiled in that instance of <a class="link" href="../ref/basic_regex.html" title="basic_regex"><code class="computeroutput"><span class="identifier">basic_regex</span></code></a>.
 144       </p>
 145 <p>
 146         Finally note that if you build the library with a non-default localization
 147         model, then the appropriate pre-processor symbol (BOOST_REGEX_USE_C_LOCALE
 148         or BOOST_REGEX_USE_CPP_LOCALE) must be defined both when you build the support
 149         library, and when you include <code class="computeroutput"><span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">regex</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span></code>
 150         or <code class="computeroutput"><span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">cregex</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span></code>
 151         in your code. The best way to ensure this is to add the #define to <code class="computeroutput"><span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">regex</span><span class="special">/</span><span class="identifier">user</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span></code>.
 152       </p>
 153 <h5>
 154 <a name="boost_regex.background_information.locale.h3"></a>
 155         <span><a name="boost_regex.background_information.locale.providing_a_message_catalogue"></a></span><a class="link" href="locale.html#boost_regex.background_information.locale.providing_a_message_catalogue">Providing
 156         a message catalogue</a>
 157       </h5>
 158 <p>
 159         In order to localize the front end of the library, you need to provide the
 160         library with the appropriate message strings contained either in a resource
 161         dll's string table (Win32 model), or a POSIX message catalogue (C++ models).
 162         In the latter case the messages must appear in message set zero of the catalogue.
 163         The messages and their id's are as follows:
 164       </p>
 165 <div class="informaltable"><table class="table">
 166 <colgroup>
 167 <col>
 168 <col>
 169 <col>
 170 </colgroup>
 171 <thead><tr>
 172 <th>
 173                 <p>
 174                   Message
 175                 </p>
 176               </th>
 177 <th>
 178                 <p>
 179                   id
 180                 </p>
 181               </th>
 182 <th>
 183                 <p>
 184                   Meaning
 185                 </p>
 186               </th>
 187 <th>
 188                 <p>
 189                   Default value
 190                 </p>
 191               </th>
 192 </tr></thead>
 193 <tbody>
 194 <tr>
 195 <td>
 196                 <p>
 197                   101
 198                 </p>
 199               </td>
 200 <td>
 201                 <p>
 202                   The character used to start a sub-expression.
 203                 </p>
 204               </td>
 205 <td>
 206                 <p>
 207                   "("
 208                 </p>
 209               </td>
 210 </tr>
 211 <tr>
 212 <td>
 213                 <p>
 214                   102
 215                 </p>
 216               </td>
 217 <td>
 218                 <p>
 219                   The character used to end a sub-expression declaration.
 220                 </p>
 221               </td>
 222 <td>
 223                 <p>
 224                   ")"
 225                 </p>
 226               </td>
 227 </tr>
 228 <tr>
 229 <td>
 230                 <p>
 231                   103
 232                 </p>
 233               </td>
 234 <td>
 235                 <p>
 236                   The character used to denote an end of line assertion.
 237                 </p>
 238               </td>
 239 <td>
 240                 <p>
 241                   "$"
 242                 </p>
 243               </td>
 244 </tr>
 245 <tr>
 246 <td>
 247                 <p>
 248                   104
 249                 </p>
 250               </td>
 251 <td>
 252                 <p>
 253                   The character used to denote the start of line assertion.
 254                 </p>
 255               </td>
 256 <td>
 257                 <p>
 258                   "^"
 259                 </p>
 260               </td>
 261 </tr>
 262 <tr>
 263 <td>
 264                 <p>
 265                   105
 266                 </p>
 267               </td>
 268 <td>
 269                 <p>
 270                   The character used to denote the "match any character expression".
 271                 </p>
 272               </td>
 273 <td>
 274                 <p>
 275                   "."
 276                 </p>
 277               </td>
 278 </tr>
 279 <tr>
 280 <td>
 281                 <p>
 282                   106
 283                 </p>
 284               </td>
 285 <td>
 286                 <p>
 287                   The match zero or more times repetition operator.
 288                 </p>
 289               </td>
 290 <td>
 291                 <p>
 292                   "*"
 293                 </p>
 294               </td>
 295 </tr>
 296 <tr>
 297 <td>
 298                 <p>
 299                   107
 300                 </p>
 301               </td>
 302 <td>
 303                 <p>
 304                   The match one or more repetition operator.
 305                 </p>
 306               </td>
 307 <td>
 308                 <p>
 309                   "+"
 310                 </p>
 311               </td>
 312 </tr>
 313 <tr>
 314 <td>
 315                 <p>
 316                   108
 317                 </p>
 318               </td>
 319 <td>
 320                 <p>
 321                   The match zero or one repetition operator.
 322                 </p>
 323               </td>
 324 <td>
 325                 <p>
 326                   "?"
 327                 </p>
 328               </td>
 329 </tr>
 330 <tr>
 331 <td>
 332                 <p>
 333                   109
 334                 </p>
 335               </td>
 336 <td>
 337                 <p>
 338                   The character set opening character.
 339                 </p>
 340               </td>
 341 <td>
 342                 <p>
 343                   "["
 344                 </p>
 345               </td>
 346 </tr>
 347 <tr>
 348 <td>
 349                 <p>
 350                   110
 351                 </p>
 352               </td>
 353 <td>
 354                 <p>
 355                   The character set closing character.
 356                 </p>
 357               </td>
 358 <td>
 359                 <p>
 360                   "]"
 361                 </p>
 362               </td>
 363 </tr>
 364 <tr>
 365 <td>
 366                 <p>
 367                   111
 368                 </p>
 369               </td>
 370 <td>
 371                 <p>
 372                   The alternation operator.
 373                 </p>
 374               </td>
 375 <td>
 376                 <p>
 377                   "|"
 378                 </p>
 379               </td>
 380 </tr>
 381 <tr>
 382 <td>
 383                 <p>
 384                   112
 385                 </p>
 386               </td>
 387 <td>
 388                 <p>
 389                   The escape character.
 390                 </p>
 391               </td>
 392 <td>
 393                 <p>
 394                   "\"
 395                 </p>
 396               </td>
 397 </tr>
 398 <tr>
 399 <td>
 400                 <p>
 401                   113
 402                 </p>
 403               </td>
 404 <td>
 405                 <p>
 406                   The hash character (not currently used).
 407                 </p>
 408               </td>
 409 <td>
 410                 <p>
 411                   "#"
 412                 </p>
 413               </td>
 414 </tr>
 415 <tr>
 416 <td>
 417                 <p>
 418                   114
 419                 </p>
 420               </td>
 421 <td>
 422                 <p>
 423                   The range operator.
 424                 </p>
 425               </td>
 426 <td>
 427                 <p>
 428                   "-"
 429                 </p>
 430               </td>
 431 </tr>
 432 <tr>
 433 <td>
 434                 <p>
 435                   115
 436                 </p>
 437               </td>
 438 <td>
 439                 <p>
 440                   The repetition operator opening character.
 441                 </p>
 442               </td>
 443 <td>
 444                 <p>
 445                   "{"
 446                 </p>
 447               </td>
 448 </tr>
 449 <tr>
 450 <td>
 451                 <p>
 452                   116
 453                 </p>
 454               </td>
 455 <td>
 456                 <p>
 457                   The repetition operator closing character.
 458                 </p>
 459               </td>
 460 <td>
 461                 <p>
 462                   "}"
 463                 </p>
 464               </td>
 465 </tr>
 466 <tr>
 467 <td>
 468                 <p>
 469                   117
 470                 </p>
 471               </td>
 472 <td>
 473                 <p>
 474                   The digit characters.
 475                 </p>
 476               </td>
 477 <td>
 478                 <p>
 479                   "0123456789"
 480                 </p>
 481               </td>
 482 </tr>
 483 <tr>
 484 <td>
 485                 <p>
 486                   118
 487                 </p>
 488               </td>
 489 <td>
 490                 <p>
 491                   The character which when preceded by an escape character represents
 492                   the word boundary assertion.
 493                 </p>
 494               </td>
 495 <td>
 496                 <p>
 497                   "b"
 498                 </p>
 499               </td>
 500 </tr>
 501 <tr>
 502 <td>
 503                 <p>
 504                   119
 505                 </p>
 506               </td>
 507 <td>
 508                 <p>
 509                   The character which when preceded by an escape character represents
 510                   the non-word boundary assertion.
 511                 </p>
 512               </td>
 513 <td>
 514                 <p>
 515                   "B"
 516                 </p>
 517               </td>
 518 </tr>
 519 <tr>
 520 <td>
 521                 <p>
 522                   120
 523                 </p>
 524               </td>
 525 <td>
 526                 <p>
 527                   The character which when preceded by an escape character represents
 528                   the word-start boundary assertion.
 529                 </p>
 530               </td>
 531 <td>
 532                 <p>
 533                   "&lt;"
 534                 </p>
 535               </td>
 536 </tr>
 537 <tr>
 538 <td>
 539                 <p>
 540                   121
 541                 </p>
 542               </td>
 543 <td>
 544                 <p>
 545                   The character which when preceded by an escape character represents
 546                   the word-end boundary assertion.
 547                 </p>
 548               </td>
 549 <td>
 550                 <p>
 551                   "&gt;"
 552                 </p>
 553               </td>
 554 </tr>
 555 <tr>
 556 <td>
 557                 <p>
 558                   122
 559                 </p>
 560               </td>
 561 <td>
 562                 <p>
 563                   The character which when preceded by an escape character represents
 564                   any word character.
 565                 </p>
 566               </td>
 567 <td>
 568                 <p>
 569                   "w"
 570                 </p>
 571               </td>
 572 </tr>
 573 <tr>
 574 <td>
 575                 <p>
 576                   123
 577                 </p>
 578               </td>
 579 <td>
 580                 <p>
 581                   The character which when preceded by an escape character represents
 582                   a non-word character.
 583                 </p>
 584               </td>
 585 <td>
 586                 <p>
 587                   "W"
 588                 </p>
 589               </td>
 590 </tr>
 591 <tr>
 592 <td>
 593                 <p>
 594                   124
 595                 </p>
 596               </td>
 597 <td>
 598                 <p>
 599                   The character which when preceded by an escape character represents
 600                   a start of buffer assertion.
 601                 </p>
 602               </td>
 603 <td>
 604                 <p>
 605                   "`A"
 606                 </p>
 607               </td>
 608 </tr>
 609 <tr>
 610 <td>
 611                 <p>
 612                   125
 613                 </p>
 614               </td>
 615 <td>
 616                 <p>
 617                   The character which when preceded by an escape character represents
 618                   an end of buffer assertion.
 619                 </p>
 620               </td>
 621 <td>
 622                 <p>
 623                   "'z"
 624                 </p>
 625               </td>
 626 </tr>
 627 <tr>
 628 <td>
 629                 <p>
 630                   126
 631                 </p>
 632               </td>
 633 <td>
 634                 <p>
 635                   The newline character.
 636                 </p>
 637               </td>
 638 <td>
 639                 <p>
 640                   "\n"
 641                 </p>
 642               </td>
 643 </tr>
 644 <tr>
 645 <td>
 646                 <p>
 647                   127
 648                 </p>
 649               </td>
 650 <td>
 651                 <p>
 652                   The comma separator.
 653                 </p>
 654               </td>
 655 <td>
 656                 <p>
 657                   ","
 658                 </p>
 659               </td>
 660 </tr>
 661 <tr>
 662 <td>
 663                 <p>
 664                   128
 665                 </p>
 666               </td>
 667 <td>
 668                 <p>
 669                   The character which when preceded by an escape character represents
 670                   the bell character.
 671                 </p>
 672               </td>
 673 <td>
 674                 <p>
 675                   "a"
 676                 </p>
 677               </td>
 678 </tr>
 679 <tr>
 680 <td>
 681                 <p>
 682                   129
 683                 </p>
 684               </td>
 685 <td>
 686                 <p>
 687                   The character which when preceded by an escape character represents
 688                   the form feed character.
 689                 </p>
 690               </td>
 691 <td>
 692                 <p>
 693                   "f"
 694                 </p>
 695               </td>
 696 </tr>
 697 <tr>
 698 <td>
 699                 <p>
 700                   130
 701                 </p>
 702               </td>
 703 <td>
 704                 <p>
 705                   The character which when preceded by an escape character represents
 706                   the newline character.
 707                 </p>
 708               </td>
 709 <td>
 710                 <p>
 711                   "n"
 712                 </p>
 713               </td>
 714 </tr>
 715 <tr>
 716 <td>
 717                 <p>
 718                   131
 719                 </p>
 720               </td>
 721 <td>
 722                 <p>
 723                   The character which when preceded by an escape character represents
 724                   the carriage return character.
 725                 </p>
 726               </td>
 727 <td>
 728                 <p>
 729                   "r"
 730                 </p>
 731               </td>
 732 </tr>
 733 <tr>
 734 <td>
 735                 <p>
 736                   132
 737                 </p>
 738               </td>
 739 <td>
 740                 <p>
 741                   The character which when preceded by an escape character represents
 742                   the tab character.
 743                 </p>
 744               </td>
 745 <td>
 746                 <p>
 747                   "t"
 748                 </p>
 749               </td>
 750 </tr>
 751 <tr>
 752 <td>
 753                 <p>
 754                   133
 755                 </p>
 756               </td>
 757 <td>
 758                 <p>
 759                   The character which when preceded by an escape character represents
 760                   the vertical tab character.
 761                 </p>
 762               </td>
 763 <td>
 764                 <p>
 765                   "v"
 766                 </p>
 767               </td>
 768 </tr>
 769 <tr>
 770 <td>
 771                 <p>
 772                   134
 773                 </p>
 774               </td>
 775 <td>
 776                 <p>
 777                   The character which when preceded by an escape character represents
 778                   the start of a hexadecimal character constant.
 779                 </p>
 780               </td>
 781 <td>
 782                 <p>
 783                   "x"
 784                 </p>
 785               </td>
 786 </tr>
 787 <tr>
 788 <td>
 789                 <p>
 790                   135
 791                 </p>
 792               </td>
 793 <td>
 794                 <p>
 795                   The character which when preceded by an escape character represents
 796                   the start of an ASCII escape character.
 797                 </p>
 798               </td>
 799 <td>
 800                 <p>
 801                   "c"
 802                 </p>
 803               </td>
 804 </tr>
 805 <tr>
 806 <td>
 807                 <p>
 808                   136
 809                 </p>
 810               </td>
 811 <td>
 812                 <p>
 813                   The colon character.
 814                 </p>
 815               </td>
 816 <td>
 817                 <p>
 818                   ":"
 819                 </p>
 820               </td>
 821 </tr>
 822 <tr>
 823 <td>
 824                 <p>
 825                   137
 826                 </p>
 827               </td>
 828 <td>
 829                 <p>
 830                   The equals character.
 831                 </p>
 832               </td>
 833 <td>
 834                 <p>
 835                   "="
 836                 </p>
 837               </td>
 838 </tr>
 839 <tr>
 840 <td>
 841                 <p>
 842                   138
 843                 </p>
 844               </td>
 845 <td>
 846                 <p>
 847                   The character which when preceded by an escape character represents
 848                   the ASCII escape character.
 849                 </p>
 850               </td>
 851 <td>
 852                 <p>
 853                   "e"
 854                 </p>
 855               </td>
 856 </tr>
 857 <tr>
 858 <td>
 859                 <p>
 860                   139
 861                 </p>
 862               </td>
 863 <td>
 864                 <p>
 865                   The character which when preceded by an escape character represents
 866                   any lower case character.
 867                 </p>
 868               </td>
 869 <td>
 870                 <p>
 871                   "l"
 872                 </p>
 873               </td>
 874 </tr>
 875 <tr>
 876 <td>
 877                 <p>
 878                   140
 879                 </p>
 880               </td>
 881 <td>
 882                 <p>
 883                   The character which when preceded by an escape character represents
 884                   any non-lower case character.
 885                 </p>
 886               </td>
 887 <td>
 888                 <p>
 889                   "L"
 890                 </p>
 891               </td>
 892 </tr>
 893 <tr>
 894 <td>
 895                 <p>
 896                   141
 897                 </p>
 898               </td>
 899 <td>
 900                 <p>
 901                   The character which when preceded by an escape character represents
 902                   any upper case character.
 903                 </p>
 904               </td>
 905 <td>
 906                 <p>
 907                   "u"
 908                 </p>
 909               </td>
 910 </tr>
 911 <tr>
 912 <td>
 913                 <p>
 914                   142
 915                 </p>
 916               </td>
 917 <td>
 918                 <p>
 919                   The character which when preceded by an escape character represents
 920                   any non-upper case character.
 921                 </p>
 922               </td>
 923 <td>
 924                 <p>
 925                   "U"
 926                 </p>
 927               </td>
 928 </tr>
 929 <tr>
 930 <td>
 931                 <p>
 932                   143
 933                 </p>
 934               </td>
 935 <td>
 936                 <p>
 937                   The character which when preceded by an escape character represents
 938                   any space character.
 939                 </p>
 940               </td>
 941 <td>
 942                 <p>
 943                   "s"
 944                 </p>
 945               </td>
 946 </tr>
 947 <tr>
 948 <td>
 949                 <p>
 950                   144
 951                 </p>
 952               </td>
 953 <td>
 954                 <p>
 955                   The character which when preceded by an escape character represents
 956                   any non-space character.
 957                 </p>
 958               </td>
 959 <td>
 960                 <p>
 961                   "S"
 962                 </p>
 963               </td>
 964 </tr>
 965 <tr>
 966 <td>
 967                 <p>
 968                   145
 969                 </p>
 970               </td>
 971 <td>
 972                 <p>
 973                   The character which when preceded by an escape character represents
 974                   any digit character.
 975                 </p>
 976               </td>
 977 <td>
 978                 <p>
 979                   "d"
 980                 </p>
 981               </td>
 982 </tr>
 983 <tr>
 984 <td>
 985                 <p>
 986                   146
 987                 </p>
 988               </td>
 989 <td>
 990                 <p>
 991                   The character which when preceded by an escape character represents
 992                   any non-digit character.
 993                 </p>
 994               </td>
 995 <td>
 996                 <p>
 997                   "D"
 998                 </p>
 999               </td>
1000 </tr>
1001 <tr>
1002 <td>
1003                 <p>
1004                   147
1005                 </p>
1006               </td>
1007 <td>
1008                 <p>
1009                   The character which when preceded by an escape character represents
1010                   the end quote operator.
1011                 </p>
1012               </td>
1013 <td>
1014                 <p>
1015                   "E"
1016                 </p>
1017               </td>
1018 </tr>
1019 <tr>
1020 <td>
1021                 <p>
1022                   148
1023                 </p>
1024               </td>
1025 <td>
1026                 <p>
1027                   The character which when preceded by an escape character represents
1028                   the start quote operator.
1029                 </p>
1030               </td>
1031 <td>
1032                 <p>
1033                   "Q"
1034                 </p>
1035               </td>
1036 </tr>
1037 <tr>
1038 <td>
1039                 <p>
1040                   149
1041                 </p>
1042               </td>
1043 <td>
1044                 <p>
1045                   The character which when preceded by an escape character represents
1046                   a Unicode combining character sequence.
1047                 </p>
1048               </td>
1049 <td>
1050                 <p>
1051                   "X"
1052                 </p>
1053               </td>
1054 </tr>
1055 <tr>
1056 <td>
1057                 <p>
1058                   150
1059                 </p>
1060               </td>
1061 <td>
1062                 <p>
1063                   The character which when preceded by an escape character represents
1064                   any single character.
1065                 </p>
1066               </td>
1067 <td>
1068                 <p>
1069                   "C"
1070                 </p>
1071               </td>
1072 </tr>
1073 <tr>
1074 <td>
1075                 <p>
1076                   151
1077                 </p>
1078               </td>
1079 <td>
1080                 <p>
1081                   The character which when preceded by an escape character represents
1082                   end of buffer operator.
1083                 </p>
1084               </td>
1085 <td>
1086                 <p>
1087                   "Z"
1088                 </p>
1089               </td>
1090 </tr>
1091 <tr>
1092 <td>
1093                 <p>
1094                   152
1095                 </p>
1096               </td>
1097 <td>
1098                 <p>
1099                   The character which when preceded by an escape character represents
1100                   the continuation assertion.
1101                 </p>
1102               </td>
1103 <td>
1104                 <p>
1105                   "G"
1106                 </p>
1107               </td>
1108 </tr>
1109 <tr>
1110 <td>
1111                 <p>
1112                   153
1113                 </p>
1114               </td>
1115 <td>
1116                 <p>
1117                   The character which when preceeded by (? indicates a zero width
1118                   negated forward lookahead assert.
1119                 </p>
1120               </td>
1121 <td>
1122                 <p>
1123                   !
1124                 </p>
1125               </td>
1126 </tr>
1127 </tbody>
1128 </table></div>
1129 <p>
1130         Custom error messages are loaded as follows:
1131       </p>
1132 <div class="informaltable"><table class="table">
1133 <colgroup>
1134 <col>
1135 <col>
1136 <col>
1137 </colgroup>
1138 <thead><tr>
1139 <th>
1140                 <p>
1141                   Message ID
1142                 </p>
1143               </th>
1144 <th>
1145                 <p>
1146                   Error message ID
1147                 </p>
1148               </th>
1149 <th>
1150                 <p>
1151                   Default string
1152                 </p>
1153               </th>
1154 </tr></thead>
1155 <tbody>
1156 <tr>
1157 <td>
1158                 <p>
1159                   201
1160                 </p>
1161               </td>
1162 <td>
1163                 <p>
1164                   REG_NOMATCH
1165                 </p>
1166               </td>
1167 <td>
1168                 <p>
1169                   "No match"
1170                 </p>
1171               </td>
1172 </tr>
1173 <tr>
1174 <td>
1175                 <p>
1176                   202
1177                 </p>
1178               </td>
1179 <td>
1180                 <p>
1181                   REG_BADPAT
1182                 </p>
1183               </td>
1184 <td>
1185                 <p>
1186                   "Invalid regular expression"
1187                 </p>
1188               </td>
1189 </tr>
1190 <tr>
1191 <td>
1192                 <p>
1193                   203
1194                 </p>
1195               </td>
1196 <td>
1197                 <p>
1198                   REG_ECOLLATE
1199                 </p>
1200               </td>
1201 <td>
1202                 <p>
1203                   "Invalid collation character"
1204                 </p>
1205               </td>
1206 </tr>
1207 <tr>
1208 <td>
1209                 <p>
1210                   204
1211                 </p>
1212               </td>
1213 <td>
1214                 <p>
1215                   REG_ECTYPE
1216                 </p>
1217               </td>
1218 <td>
1219                 <p>
1220                   "Invalid character class name"
1221                 </p>
1222               </td>
1223 </tr>
1224 <tr>
1225 <td>
1226                 <p>
1227                   205
1228                 </p>
1229               </td>
1230 <td>
1231                 <p>
1232                   REG_EESCAPE
1233                 </p>
1234               </td>
1235 <td>
1236                 <p>
1237                   "Trailing backslash"
1238                 </p>
1239               </td>
1240 </tr>
1241 <tr>
1242 <td>
1243                 <p>
1244                   206
1245                 </p>
1246               </td>
1247 <td>
1248                 <p>
1249                   REG_ESUBREG
1250                 </p>
1251               </td>
1252 <td>
1253                 <p>
1254                   "Invalid back reference"
1255                 </p>
1256               </td>
1257 </tr>
1258 <tr>
1259 <td>
1260                 <p>
1261                   207
1262                 </p>
1263               </td>
1264 <td>
1265                 <p>
1266                   REG_EBRACK
1267                 </p>
1268               </td>
1269 <td>
1270                 <p>
1271                   "Unmatched [ or <code class="literal">" </code>
1272                 </p>
1273               </td>
1274 <td>
1275                 <p>
1276                   [208
1277                 </p>
1278               </td>
1279 <td>
1280                 <p>
1281                   REG_EPAREN
1282                 </p>
1283               </td>
1284 <td>
1285                 <p>
1286                   "Unmatched ( or \("
1287                 </p>
1288               </td>
1289 </tr>
1290 <tr>
1291 <td>
1292                 <p>
1293                   209
1294                 </p>
1295               </td>
1296 <td>
1297                 <p>
1298                   REG_EBRACE
1299                 </p>
1300               </td>
1301 <td>
1302                 <p>
1303                   "Unmatched \{"
1304                 </p>
1305               </td>
1306 </tr>
1307 <tr>
1308 <td>
1309                 <p>
1310                   210
1311                 </p>
1312               </td>
1313 <td>
1314                 <p>
1315                   REG_BADBR
1316                 </p>
1317               </td>
1318 <td>
1319                 <p>
1320                   "Invalid content of \{\}"
1321                 </p>
1322               </td>
1323 </tr>
1324 <tr>
1325 <td>
1326                 <p>
1327                   211
1328                 </p>
1329               </td>
1330 <td>
1331                 <p>
1332                   REG_ERANGE
1333                 </p>
1334               </td>
1335 <td>
1336                 <p>
1337                   "Invalid range end"
1338                 </p>
1339               </td>
1340 </tr>
1341 <tr>
1342 <td>
1343                 <p>
1344                   212
1345                 </p>
1346               </td>
1347 <td>
1348                 <p>
1349                   REG_ESPACE
1350                 </p>
1351               </td>
1352 <td>
1353                 <p>
1354                   "Memory exhausted"
1355                 </p>
1356               </td>
1357 </tr>
1358 <tr>
1359 <td>
1360                 <p>
1361                   213
1362                 </p>
1363               </td>
1364 <td>
1365                 <p>
1366                   REG_BADRPT
1367                 </p>
1368               </td>
1369 <td>
1370                 <p>
1371                   "Invalid preceding regular expression"
1372                 </p>
1373               </td>
1374 </tr>
1375 <tr>
1376 <td>
1377                 <p>
1378                   214
1379                 </p>
1380               </td>
1381 <td>
1382                 <p>
1383                   REG_EEND
1384                 </p>
1385               </td>
1386 <td>
1387                 <p>
1388                   "Premature end of regular expression"
1389                 </p>
1390               </td>
1391 </tr>
1392 <tr>
1393 <td>
1394                 <p>
1395                   215
1396                 </p>
1397               </td>
1398 <td>
1399                 <p>
1400                   REG_ESIZE
1401                 </p>
1402               </td>
1403 <td>
1404                 <p>
1405                   "Regular expression too big"
1406                 </p>
1407               </td>
1408 </tr>
1409 <tr>
1410 <td>
1411                 <p>
1412                   216
1413                 </p>
1414               </td>
1415 <td>
1416                 <p>
1417                   REG_ERPAREN
1418                 </p>
1419               </td>
1420 <td>
1421                 <p>
1422                   "Unmatched ) or \)"
1423                 </p>
1424               </td>
1425 </tr>
1426 <tr>
1427 <td>
1428                 <p>
1429                   217
1430                 </p>
1431               </td>
1432 <td>
1433                 <p>
1434                   REG_EMPTY
1435                 </p>
1436               </td>
1437 <td>
1438                 <p>
1439                   "Empty expression"
1440                 </p>
1441               </td>
1442 </tr>
1443 <tr>
1444 <td>
1445                 <p>
1446                   218
1447                 </p>
1448               </td>
1449 <td>
1450                 <p>
1451                   REG_E_UNKNOWN
1452                 </p>
1453               </td>
1454 <td>
1455                 <p>
1456                   "Unknown error"
1457                 </p>
1458               </td>
1459 </tr>
1460 </tbody>
1461 </table></div>
1462 <p>
1463         Custom character class names are loaded as followed:
1464       </p>
1465 <div class="informaltable"><table class="table">
1466 <colgroup>
1467 <col>
1468 <col>
1469 <col>
1470 </colgroup>
1471 <thead><tr>
1472 <th>
1473                 <p>
1474                   Message ID
1475                 </p>
1476               </th>
1477 <th>
1478                 <p>
1479                   Description
1480                 </p>
1481               </th>
1482 <th>
1483                 <p>
1484                   Equivalent default class name
1485                 </p>
1486               </th>
1487 </tr></thead>
1488 <tbody>
1489 <tr>
1490 <td>
1491                 <p>
1492                   300
1493                 </p>
1494               </td>
1495 <td>
1496                 <p>
1497                   The character class name for alphanumeric characters.
1498                 </p>
1499               </td>
1500 <td>
1501                 <p>
1502                   "alnum"
1503                 </p>
1504               </td>
1505 </tr>
1506 <tr>
1507 <td>
1508                 <p>
1509                   301
1510                 </p>
1511               </td>
1512 <td>
1513                 <p>
1514                   The character class name for alphabetic characters.
1515                 </p>
1516               </td>
1517 <td>
1518                 <p>
1519                   "alpha"
1520                 </p>
1521               </td>
1522 </tr>
1523 <tr>
1524 <td>
1525                 <p>
1526                   302
1527                 </p>
1528               </td>
1529 <td>
1530                 <p>
1531                   The character class name for control characters.
1532                 </p>
1533               </td>
1534 <td>
1535                 <p>
1536                   "cntrl"
1537                 </p>
1538               </td>
1539 </tr>
1540 <tr>
1541 <td>
1542                 <p>
1543                   303
1544                 </p>
1545               </td>
1546 <td>
1547                 <p>
1548                   The character class name for digit characters.
1549                 </p>
1550               </td>
1551 <td>
1552                 <p>
1553                   "digit"
1554                 </p>
1555               </td>
1556 </tr>
1557 <tr>
1558 <td>
1559                 <p>
1560                   304
1561                 </p>
1562               </td>
1563 <td>
1564                 <p>
1565                   The character class name for graphics characters.
1566                 </p>
1567               </td>
1568 <td>
1569                 <p>
1570                   "graph"
1571                 </p>
1572               </td>
1573 </tr>
1574 <tr>
1575 <td>
1576                 <p>
1577                   305
1578                 </p>
1579               </td>
1580 <td>
1581                 <p>
1582                   The character class name for lower case characters.
1583                 </p>
1584               </td>
1585 <td>
1586                 <p>
1587                   "lower"
1588                 </p>
1589               </td>
1590 </tr>
1591 <tr>
1592 <td>
1593                 <p>
1594                   306
1595                 </p>
1596               </td>
1597 <td>
1598                 <p>
1599                   The character class name for printable characters.
1600                 </p>
1601               </td>
1602 <td>
1603                 <p>
1604                   "print"
1605                 </p>
1606               </td>
1607 </tr>
1608 <tr>
1609 <td>
1610                 <p>
1611                   307
1612                 </p>
1613               </td>
1614 <td>
1615                 <p>
1616                   The character class name for punctuation characters.
1617                 </p>
1618               </td>
1619 <td>
1620                 <p>
1621                   "punct"
1622                 </p>
1623               </td>
1624 </tr>
1625 <tr>
1626 <td>
1627                 <p>
1628                   308
1629                 </p>
1630               </td>
1631 <td>
1632                 <p>
1633                   The character class name for space characters.
1634                 </p>
1635               </td>
1636 <td>
1637                 <p>
1638                   "space"
1639                 </p>
1640               </td>
1641 </tr>
1642 <tr>
1643 <td>
1644                 <p>
1645                   309
1646                 </p>
1647               </td>
1648 <td>
1649                 <p>
1650                   The character class name for upper case characters.
1651                 </p>
1652               </td>
1653 <td>
1654                 <p>
1655                   "upper"
1656                 </p>
1657               </td>
1658 </tr>
1659 <tr>
1660 <td>
1661                 <p>
1662                   310
1663                 </p>
1664               </td>
1665 <td>
1666                 <p>
1667                   The character class name for hexadecimal characters.
1668                 </p>
1669               </td>
1670 <td>
1671                 <p>
1672                   "xdigit"
1673                 </p>
1674               </td>
1675 </tr>
1676 <tr>
1677 <td>
1678                 <p>
1679                   311
1680                 </p>
1681               </td>
1682 <td>
1683                 <p>
1684                   The character class name for blank characters.
1685                 </p>
1686               </td>
1687 <td>
1688                 <p>
1689                   "blank"
1690                 </p>
1691               </td>
1692 </tr>
1693 <tr>
1694 <td>
1695                 <p>
1696                   312
1697                 </p>
1698               </td>
1699 <td>
1700                 <p>
1701                   The character class name for word characters.
1702                 </p>
1703               </td>
1704 <td>
1705                 <p>
1706                   "word"
1707                 </p>
1708               </td>
1709 </tr>
1710 <tr>
1711 <td>
1712                 <p>
1713                   313
1714                 </p>
1715               </td>
1716 <td>
1717                 <p>
1718                   The character class name for Unicode characters.
1719                 </p>
1720               </td>
1721 <td>
1722                 <p>
1723                   "unicode"
1724                 </p>
1725               </td>
1726 </tr>
1727 </tbody>
1728 </table></div>
1729 <p>
1730         Finally, custom collating element names are loaded starting from message
1731         id 400, and terminating when the first load thereafter fails. Each message
1732         looks something like: "tagname string" where tagname is the name
1733         used inside [[.tagname.]] and string is the actual text of the collating
1734         element. Note that the value of collating element [[.zero.]] is used for
1735         the conversion of strings to numbers - if you replace this with another value
1736         then that will be used for string parsing - for example use the Unicode character
1737         0x0660 for [[.zero.]] if you want to use Unicode Arabic-Indic digits in your
1738         regular expressions in place of Latin digits.
1739       </p>
1740 <p>
1741         Note that the POSIX defined names for character classes and collating elements
1742         are always available - even if custom names are defined, in contrast, custom
1743         error messages, and custom syntax messages replace the default ones.
1744       </p>
1745 </div>
1746 <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
1747 <td align="left"></td>
1748 <td align="right"><div class="copyright-footer">Copyright &#169; 1998-2010 John Maddock<p>
1749         Distributed under the Boost Software License, Version 1.0. (See accompanying
1750         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>)
1751       </p>
1752 </div></td>
1753 </tr></table>
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