posix/regex.h

   1 /* Definitions for data structures and routines for the regular
   2    expression library.
   3    Copyright (C) 1985,1989-93,1995-98,2000,2001,2002,2003,2005,2006
   4    Free Software Foundation, Inc.
   5    This file is part of the GNU C Library.
   6
   7    The GNU C Library is free software; you can redistribute it and/or
   8    modify it under the terms of the GNU Lesser General Public
   9    License as published by the Free Software Foundation; either
  10    version 2.1 of the License, or (at your option) any later version.
  11
  12    The GNU C Library is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15    Lesser General Public License for more details.
  16
  17    You should have received a copy of the GNU Lesser General Public
  18    License along with the GNU C Library; if not, write to the Free
  19    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  20    02111-1307 USA.  */
  21
  22 #ifndef _REGEX_H
  23 #define _REGEX_H 1
  24
  25 #include <sys/types.h>
  26
  27 /* Allow the use in C++ code.  */
  28 #ifdef __cplusplus
  29 extern "C" {
  30 #endif
  31
  32 /* The following two types have to be signed and unsigned integer type
  33    wide enough to hold a value of a pointer.  For most ANSI compilers
  34    ptrdiff_t and size_t should be likely OK.  Still size of these two
  35    types is 2 for Microsoft C.  Ugh... */
  36 typedef long int s_reg_t;
  37 typedef unsigned long int active_reg_t;
  38
  39 /* The following bits are used to determine the regexp syntax we
  40    recognize.  The set/not-set meanings are chosen so that Emacs syntax
  41    remains the value 0.  The bits are given in alphabetical order, and
  42    the definitions shifted by one from the previous bit; thus, when we
  43    add or remove a bit, only one other definition need change.  */
  44 typedef unsigned long int reg_syntax_t;
  45
  46 /* If this bit is not set, then \ inside a bracket expression is literal.
  47    If set, then such a \ quotes the following character.  */
  48 #define RE_BACKSLASH_ESCAPE_IN_LISTS ((unsigned long int) 1)
  49
  50 /* If this bit is not set, then + and ? are operators, and \+ and \? are
  51      literals.
  52    If set, then \+ and \? are operators and + and ? are literals.  */
  53 #define RE_BK_PLUS_QM (RE_BACKSLASH_ESCAPE_IN_LISTS << 1)
  54
  55 /* If this bit is set, then character classes are supported.  They are:
  56      [:alpha:], [:upper:], [:lower:],  [:digit:], [:alnum:], [:xdigit:],
  57      [:space:], [:print:], [:punct:], [:graph:], and [:cntrl:].
  58    If not set, then character classes are not supported.  */
  59 #define RE_CHAR_CLASSES (RE_BK_PLUS_QM << 1)
  60
  61 /* If this bit is set, then ^ and $ are always anchors (outside bracket
  62      expressions, of course).
  63    If this bit is not set, then it depends:
  64         ^  is an anchor if it is at the beginning of a regular
  65            expression or after an open-group or an alternation operator;
  66         $  is an anchor if it is at the end of a regular expression, or
  67            before a close-group or an alternation operator.
  68
  69    This bit could be (re)combined with RE_CONTEXT_INDEP_OPS, because
  70    POSIX draft 11.2 says that * etc. in leading positions is undefined.
  71    We already implemented a previous draft which made those constructs
  72    invalid, though, so we haven't changed the code back.  */
  73 #define RE_CONTEXT_INDEP_ANCHORS (RE_CHAR_CLASSES << 1)
  74
  75 /* If this bit is set, then special characters are always special
  76      regardless of where they are in the pattern.
  77    If this bit is not set, then special characters are special only in
  78      some contexts; otherwise they are ordinary.  Specifically,
  79      * + ? and intervals are only special when not after the beginning,
  80      open-group, or alternation operator.  */
  81 #define RE_CONTEXT_INDEP_OPS (RE_CONTEXT_INDEP_ANCHORS << 1)
  82
  83 /* If this bit is set, then *, +, ?, and { cannot be first in an re or
  84      immediately after an alternation or begin-group operator.  */
  85 #define RE_CONTEXT_INVALID_OPS (RE_CONTEXT_INDEP_OPS << 1)
  86
  87 /* If this bit is set, then . matches newline.
  88    If not set, then it doesn't.  */
  89 #define RE_DOT_NEWLINE (RE_CONTEXT_INVALID_OPS << 1)
  90
  91 /* If this bit is set, then . doesn't match NUL.
  92    If not set, then it does.  */
  93 #define RE_DOT_NOT_NULL (RE_DOT_NEWLINE << 1)
  94
  95 /* If this bit is set, nonmatching lists [^...] do not match newline.
  96    If not set, they do.  */
  97 #define RE_HAT_LISTS_NOT_NEWLINE (RE_DOT_NOT_NULL << 1)
  98
  99 /* If this bit is set, either \{...\} or {...} defines an
 100      interval, depending on RE_NO_BK_BRACES.
 101    If not set, \{, \}, {, and } are literals.  */
 102 #define RE_INTERVALS (RE_HAT_LISTS_NOT_NEWLINE << 1)
 103
 104 /* If this bit is set, +, ? and | aren't recognized as operators.
 105    If not set, they are.  */
 106 #define RE_LIMITED_OPS (RE_INTERVALS << 1)
 107
 108 /* If this bit is set, newline is an alternation operator.
 109    If not set, newline is literal.  */
 110 #define RE_NEWLINE_ALT (RE_LIMITED_OPS << 1)
 111
 112 /* If this bit is set, then `{...}' defines an interval, and \{ and \}
 113      are literals.
 114   If not set, then `\{...\}' defines an interval.  */
 115 #define RE_NO_BK_BRACES (RE_NEWLINE_ALT << 1)
 116
 117 /* If this bit is set, (...) defines a group, and \( and \) are literals.
 118    If not set, \(...\) defines a group, and ( and ) are literals.  */
 119 #define RE_NO_BK_PARENS (RE_NO_BK_BRACES << 1)
 120
 121 /* If this bit is set, then \<digit> matches <digit>.
 122    If not set, then \<digit> is a back-reference.  */
 123 #define RE_NO_BK_REFS (RE_NO_BK_PARENS << 1)
 124
 125 /* If this bit is set, then | is an alternation operator, and \| is literal.
 126    If not set, then \| is an alternation operator, and | is literal.  */
 127 #define RE_NO_BK_VBAR (RE_NO_BK_REFS << 1)
 128
 129 /* If this bit is set, then an ending range point collating higher
 130      than the starting range point, as in [z-a], is invalid.
 131    If not set, then when ending range point collates higher than the
 132      starting range point, the range is ignored.  */
 133 #define RE_NO_EMPTY_RANGES (RE_NO_BK_VBAR << 1)
 134
 135 /* If this bit is set, then an unmatched ) is ordinary.
 136    If not set, then an unmatched ) is invalid.  */
 137 #define RE_UNMATCHED_RIGHT_PAREN_ORD (RE_NO_EMPTY_RANGES << 1)
 138
 139 /* If this bit is set, succeed as soon as we match the whole pattern,
 140    without further backtracking.  */
 141 #define RE_NO_POSIX_BACKTRACKING (RE_UNMATCHED_RIGHT_PAREN_ORD << 1)
 142
 143 /* If this bit is set, do not process the GNU regex operators.
 144    If not set, then the GNU regex operators are recognized. */
 145 #define RE_NO_GNU_OPS (RE_NO_POSIX_BACKTRACKING << 1)
 146
 147 /* If this bit is set, turn on internal regex debugging.
 148    If not set, and debugging was on, turn it off.
 149    This only works if regex.c is compiled -DDEBUG.
 150    We define this bit always, so that all that's needed to turn on
 151    debugging is to recompile regex.c; the calling code can always have
 152    this bit set, and it won't affect anything in the normal case. */
 153 #define RE_DEBUG (RE_NO_GNU_OPS << 1)
 154
 155 /* If this bit is set, a syntactically invalid interval is treated as
 156    a string of ordinary characters.  For example, the ERE 'a{1' is
 157    treated as 'a\{1'.  */
 158 #define RE_INVALID_INTERVAL_ORD (RE_DEBUG << 1)
 159
 160 /* If this bit is set, then ignore case when matching.
 161    If not set, then case is significant.  */
 162 #define RE_ICASE (RE_INVALID_INTERVAL_ORD << 1)
 163
 164 /* This bit is used internally like RE_CONTEXT_INDEP_ANCHORS but only
 165    for ^, because it is difficult to scan the regex backwards to find
 166    whether ^ should be special.  */
 167 #define RE_CARET_ANCHORS_HERE (RE_ICASE << 1)
 168
 169 /* If this bit is set, then \{ cannot be first in an bre or
 170    immediately after an alternation or begin-group operator.  */
 171 #define RE_CONTEXT_INVALID_DUP (RE_CARET_ANCHORS_HERE << 1)
 172
 173 /* If this bit is set, then no_sub will be set to 1 during
 174    re_compile_pattern.  */
 175 #define RE_NO_SUB (RE_CONTEXT_INVALID_DUP << 1)
 176
 177 /* This global variable defines the particular regexp syntax to use (for
 178    some interfaces).  When a regexp is compiled, the syntax used is
 179    stored in the pattern buffer, so changing this does not affect
 180    already-compiled regexps.  */
 181 extern reg_syntax_t re_syntax_options;
 182 \f
 183 /* Define combinations of the above bits for the standard possibilities.
 184    (The [[[ comments delimit what gets put into the Texinfo file, so
 185    don't delete them!)  */
 186 /* [[[begin syntaxes]]] */
 187 #define RE_SYNTAX_EMACS 0
 188
 189 #define RE_SYNTAX_AWK                                                   \
 190   (RE_BACKSLASH_ESCAPE_IN_LISTS   | RE_DOT_NOT_NULL                     \
 191    | RE_NO_BK_PARENS              | RE_NO_BK_REFS                       \
 192    | RE_NO_BK_VBAR                | RE_NO_EMPTY_RANGES                  \
 193    | RE_DOT_NEWLINE               | RE_CONTEXT_INDEP_ANCHORS            \
 194    | RE_UNMATCHED_RIGHT_PAREN_ORD | RE_NO_GNU_OPS)
 195
 196 #define RE_SYNTAX_GNU_AWK                                               \
 197   ((RE_SYNTAX_POSIX_EXTENDED | RE_BACKSLASH_ESCAPE_IN_LISTS | RE_DEBUG) \
 198    & ~(RE_DOT_NOT_NULL | RE_INTERVALS | RE_CONTEXT_INDEP_OPS            \
 199        | RE_CONTEXT_INVALID_OPS ))
 200
 201 #define RE_SYNTAX_POSIX_AWK                                             \
 202   (RE_SYNTAX_POSIX_EXTENDED | RE_BACKSLASH_ESCAPE_IN_LISTS              \
 203    | RE_INTERVALS           | RE_NO_GNU_OPS)
 204
 205 #define RE_SYNTAX_GREP                                                  \
 206   (RE_BK_PLUS_QM              | RE_CHAR_CLASSES                         \
 207    | RE_HAT_LISTS_NOT_NEWLINE | RE_INTERVALS                            \
 208    | RE_NEWLINE_ALT)
 209
 210 #define RE_SYNTAX_EGREP                                                 \
 211   (RE_CHAR_CLASSES        | RE_CONTEXT_INDEP_ANCHORS                    \
 212    | RE_CONTEXT_INDEP_OPS | RE_HAT_LISTS_NOT_NEWLINE                    \
 213    | RE_NEWLINE_ALT       | RE_NO_BK_PARENS                             \
 214    | RE_NO_BK_VBAR)
 215
 216 #define RE_SYNTAX_POSIX_EGREP                                           \
 217   (RE_SYNTAX_EGREP | RE_INTERVALS | RE_NO_BK_BRACES                     \
 218    | RE_INVALID_INTERVAL_ORD)
 219
 220 /* P1003.2/D11.2, section 4.20.7.1, lines 5078ff.  */
 221 #define RE_SYNTAX_ED RE_SYNTAX_POSIX_BASIC
 222
 223 #define RE_SYNTAX_SED RE_SYNTAX_POSIX_BASIC
 224
 225 /* Syntax bits common to both basic and extended POSIX regex syntax.  */
 226 #define _RE_SYNTAX_POSIX_COMMON                                         \
 227   (RE_CHAR_CLASSES | RE_DOT_NEWLINE      | RE_DOT_NOT_NULL              \
 228    | RE_INTERVALS  | RE_NO_EMPTY_RANGES)
 229
 230 #define RE_SYNTAX_POSIX_BASIC                                           \
 231   (_RE_SYNTAX_POSIX_COMMON | RE_BK_PLUS_QM | RE_CONTEXT_INVALID_DUP)
 232
 233 /* Differs from ..._POSIX_BASIC only in that RE_BK_PLUS_QM becomes
 234    RE_LIMITED_OPS, i.e., \? \+ \| are not recognized.  Actually, this
 235    isn't minimal, since other operators, such as \`, aren't disabled.  */
 236 #define RE_SYNTAX_POSIX_MINIMAL_BASIC                                   \
 237   (_RE_SYNTAX_POSIX_COMMON | RE_LIMITED_OPS)
 238
 239 #define RE_SYNTAX_POSIX_EXTENDED                                        \
 240   (_RE_SYNTAX_POSIX_COMMON  | RE_CONTEXT_INDEP_ANCHORS                  \
 241    | RE_CONTEXT_INDEP_OPS   | RE_NO_BK_BRACES                           \
 242    | RE_NO_BK_PARENS        | RE_NO_BK_VBAR                             \
 243    | RE_CONTEXT_INVALID_OPS | RE_UNMATCHED_RIGHT_PAREN_ORD)
 244
 245 /* Differs from ..._POSIX_EXTENDED in that RE_CONTEXT_INDEP_OPS is
 246    removed and RE_NO_BK_REFS is added.  */
 247 #define RE_SYNTAX_POSIX_MINIMAL_EXTENDED                                \
 248   (_RE_SYNTAX_POSIX_COMMON  | RE_CONTEXT_INDEP_ANCHORS                  \
 249    | RE_CONTEXT_INVALID_OPS | RE_NO_BK_BRACES                           \
 250    | RE_NO_BK_PARENS        | RE_NO_BK_REFS                             \
 251    | RE_NO_BK_VBAR          | RE_UNMATCHED_RIGHT_PAREN_ORD)
 252 /* [[[end syntaxes]]] */
 253 \f
 254 /* Maximum number of duplicates an interval can allow.  Some systems
 255    (erroneously) define this in other header files, but we want our
 256    value, so remove any previous define.  */
 257 #ifdef RE_DUP_MAX
 258 # undef RE_DUP_MAX
 259 #endif
 260 /* If sizeof(int) == 2, then ((1 << 15) - 1) overflows.  */
 261 #define RE_DUP_MAX (0x7fff)
 262
 263
 264 /* POSIX `cflags' bits (i.e., information for `regcomp').  */
 265
 266 /* If this bit is set, then use extended regular expression syntax.
 267    If not set, then use basic regular expression syntax.  */
 268 #define REG_EXTENDED 1
 269
 270 /* If this bit is set, then ignore case when matching.
 271    If not set, then case is significant.  */
 272 #define REG_ICASE (REG_EXTENDED << 1)
 273
 274 /* If this bit is set, then anchors do not match at newline
 275      characters in the string.
 276    If not set, then anchors do match at newlines.  */
 277 #define REG_NEWLINE (REG_ICASE << 1)
 278
 279 /* If this bit is set, then report only success or fail in regexec.
 280    If not set, then returns differ between not matching and errors.  */
 281 #define REG_NOSUB (REG_NEWLINE << 1)
 282
 283
 284 /* POSIX `eflags' bits (i.e., information for regexec).  */
 285
 286 /* If this bit is set, then the beginning-of-line operator doesn't match
 287      the beginning of the string (presumably because it's not the
 288      beginning of a line).
 289    If not set, then the beginning-of-line operator does match the
 290      beginning of the string.  */
 291 #define REG_NOTBOL 1
 292
 293 /* Like REG_NOTBOL, except for the end-of-line.  */
 294 #define REG_NOTEOL (1 << 1)
 295
 296 /* Use PMATCH[0] to delimit the start and end of the search in the
 297    buffer.  */
 298 #define REG_STARTEND (1 << 2)
 299
 300
 301 /* If any error codes are removed, changed, or added, update the
 302    `re_error_msg' table in regex.c.  */
 303 typedef enum
 304 {
 305 #ifdef _XOPEN_SOURCE
 306   REG_ENOSYS = -1,      /* This will never happen for this implementation.  */
 307 #endif
 308
 309   REG_NOERROR = 0,      /* Success.  */
 310   REG_NOMATCH,          /* Didn't find a match (for regexec).  */
 311
 312   /* POSIX regcomp return error codes.  (In the order listed in the
 313      standard.)  */
 314   REG_BADPAT,           /* Invalid pattern.  */
 315   REG_ECOLLATE,         /* Inalid collating element.  */
 316   REG_ECTYPE,           /* Invalid character class name.  */
 317   REG_EESCAPE,          /* Trailing backslash.  */
 318   REG_ESUBREG,          /* Invalid back reference.  */
 319   REG_EBRACK,           /* Unmatched left bracket.  */
 320   REG_EPAREN,           /* Parenthesis imbalance.  */
 321   REG_EBRACE,           /* Unmatched \{.  */
 322   REG_BADBR,            /* Invalid contents of \{\}.  */
 323   REG_ERANGE,           /* Invalid range end.  */
 324   REG_ESPACE,           /* Ran out of memory.  */
 325   REG_BADRPT,           /* No preceding re for repetition op.  */
 326
 327   /* Error codes we've added.  */
 328   REG_EEND,             /* Premature end.  */
 329   REG_ESIZE,            /* Compiled pattern bigger than 2^16 bytes.  */
 330   REG_ERPAREN           /* Unmatched ) or \); not returned from regcomp.  */
 331 } reg_errcode_t;
 332 \f
 333 /* This data structure represents a compiled pattern.  Before calling
 334    the pattern compiler, the fields `buffer', `allocated', `fastmap',
 335    `translate', and `no_sub' can be set.  After the pattern has been
 336    compiled, the `re_nsub' field is available.  All other fields are
 337    private to the regex routines.  */
 338
 339 #ifndef RE_TRANSLATE_TYPE
 340 # define RE_TRANSLATE_TYPE unsigned char *
 341 #endif
 342
 343 struct re_pattern_buffer
 344 {
 345   /* Space that holds the compiled pattern.  It is declared as
 346      `unsigned char *' because its elements are sometimes used as
 347      array indexes.  */
 348   unsigned char *buffer;
 349
 350   /* Number of bytes to which `buffer' points.  */
 351   unsigned long int allocated;
 352
 353   /* Number of bytes actually used in `buffer'.  */
 354   unsigned long int used;
 355
 356   /* Syntax setting with which the pattern was compiled.  */
 357   reg_syntax_t syntax;
 358
 359   /* Pointer to a fastmap, if any, otherwise zero.  re_search uses the
 360      fastmap, if there is one, to skip over impossible starting points
 361      for matches.  */
 362   char *fastmap;
 363
 364   /* Either a translate table to apply to all characters before
 365      comparing them, or zero for no translation.  The translation is
 366      applied to a pattern when it is compiled and to a string when it
 367      is matched.  */
 368   RE_TRANSLATE_TYPE translate;
 369
 370   /* Number of subexpressions found by the compiler.  */
 371   size_t re_nsub;
 372
 373   /* Zero if this pattern cannot match the empty string, one else.
 374      Well, in truth it's used only in `re_search_2', to see whether or
 375      not we should use the fastmap, so we don't set this absolutely
 376      perfectly; see `re_compile_fastmap' (the `duplicate' case).  */
 377   unsigned can_be_null : 1;
 378
 379   /* If REGS_UNALLOCATED, allocate space in the `regs' structure
 380      for `max (RE_NREGS, re_nsub + 1)' groups.
 381      If REGS_REALLOCATE, reallocate space if necessary.
 382      If REGS_FIXED, use what's there.  */
 383 #define REGS_UNALLOCATED 0
 384 #define REGS_REALLOCATE 1
 385 #define REGS_FIXED 2
 386   unsigned regs_allocated : 2;
 387
 388   /* Set to zero when `regex_compile' compiles a pattern; set to one
 389      by `re_compile_fastmap' if it updates the fastmap.  */
 390   unsigned fastmap_accurate : 1;
 391
 392   /* If set, `re_match_2' does not return information about
 393      subexpressions.  */
 394   unsigned no_sub : 1;
 395
 396   /* If set, a beginning-of-line anchor doesn't match at the beginning
 397      of the string.  */
 398   unsigned not_bol : 1;
 399
 400   /* Similarly for an end-of-line anchor.  */
 401   unsigned not_eol : 1;
 402
 403   /* If true, an anchor at a newline matches.  */
 404   unsigned newline_anchor : 1;
 405 };
 406
 407 typedef struct re_pattern_buffer regex_t;
 408 \f
 409 /* Type for byte offsets within the string.  POSIX mandates this.  */
 410 typedef int regoff_t;
 411
 412
 413 /* This is the structure we store register match data in.  See
 414    regex.texinfo for a full description of what registers match.  */
 415 struct re_registers
 416 {
 417   unsigned num_regs;
 418   regoff_t *start;
 419   regoff_t *end;
 420 };
 421
 422
 423 /* If `regs_allocated' is REGS_UNALLOCATED in the pattern buffer,
 424    `re_match_2' returns information about at least this many registers
 425    the first time a `regs' structure is passed.  */
 426 #ifndef RE_NREGS
 427 # define RE_NREGS 30
 428 #endif
 429
 430
 431 /* POSIX specification for registers.  Aside from the different names than
 432    `re_registers', POSIX uses an array of structures, instead of a
 433    structure of arrays.  */
 434 typedef struct
 435 {
 436   regoff_t rm_so;  /* Byte offset from string's start to substring's start.  */
 437   regoff_t rm_eo;  /* Byte offset from string's start to substring's end.  */
 438 } regmatch_t;
 439 \f
 440 /* Declarations for routines.  */
 441
 442 /* Sets the current default syntax to SYNTAX, and return the old syntax.
 443    You can also simply assign to the `re_syntax_options' variable.  */
 444 extern reg_syntax_t re_set_syntax (reg_syntax_t __syntax);
 445
 446 /* Compile the regular expression PATTERN, with length LENGTH
 447    and syntax given by the global `re_syntax_options', into the buffer
 448    BUFFER.  Return NULL if successful, and an error string if not.  */
 449 extern const char *re_compile_pattern (const char *__pattern, size_t __length,
 450                                        struct re_pattern_buffer *__buffer);
 451
 452
 453 /* Compile a fastmap for the compiled pattern in BUFFER; used to
 454    accelerate searches.  Return 0 if successful and -2 if was an
 455    internal error.  */
 456 extern int re_compile_fastmap (struct re_pattern_buffer *__buffer);
 457
 458
 459 /* Search in the string STRING (with length LENGTH) for the pattern
 460    compiled into BUFFER.  Start searching at position START, for RANGE
 461    characters.  Return the starting position of the match, -1 for no
 462    match, or -2 for an internal error.  Also return register
 463    information in REGS (if REGS and BUFFER->no_sub are nonzero).  */
 464 extern int re_search (struct re_pattern_buffer *__buffer, const char *__string,
 465                       int __length, int __start, int __range,
 466                       struct re_registers *__regs);
 467
 468
 469 /* Like `re_search', but search in the concatenation of STRING1 and
 470    STRING2.  Also, stop searching at index START + STOP.  */
 471 extern int re_search_2 (struct re_pattern_buffer *__buffer,
 472                         const char *__string1, int __length1,
 473                         const char *__string2, int __length2, int __start,
 474                         int __range, struct re_registers *__regs, int __stop);
 475
 476
 477 /* Like `re_search', but return how many characters in STRING the regexp
 478    in BUFFER matched, starting at position START.  */
 479 extern int re_match (struct re_pattern_buffer *__buffer, const char *__string,
 480                      int __length, int __start, struct re_registers *__regs);
 481
 482
 483 /* Relates to `re_match' as `re_search_2' relates to `re_search'.  */
 484 extern int re_match_2 (struct re_pattern_buffer *__buffer,
 485                        const char *__string1, int __length1,
 486                        const char *__string2, int __length2, int __start,
 487                        struct re_registers *__regs, int __stop);
 488
 489
 490 /* Set REGS to hold NUM_REGS registers, storing them in STARTS and
 491    ENDS.  Subsequent matches using BUFFER and REGS will use this memory
 492    for recording register information.  STARTS and ENDS must be
 493    allocated with malloc, and must each be at least `NUM_REGS * sizeof
 494    (regoff_t)' bytes long.
 495
 496    If NUM_REGS == 0, then subsequent matches should allocate their own
 497    register data.
 498
 499    Unless this function is called, the first search or match using
 500    PATTERN_BUFFER will allocate its own register data, without
 501    freeing the old data.  */
 502 extern void re_set_registers (struct re_pattern_buffer *__buffer,
 503                               struct re_registers *__regs,
 504                               unsigned int __num_regs,
 505                               regoff_t *__starts, regoff_t *__ends);
 506
 507 #if defined _REGEX_RE_COMP || defined _LIBC
 508 # ifndef _CRAY
 509 /* 4.2 bsd compatibility.  */
 510 extern char *re_comp (const char *);
 511 extern int re_exec (const char *);
 512 # endif
 513 #endif
 514
 515 /* GCC 2.95 and later have "__restrict"; C99 compilers have
 516    "restrict", and "configure" may have defined "restrict".  */
 517 #ifndef __restrict
 518 # if ! (2 < __GNUC__ || (2 == __GNUC__ && 95 <= __GNUC_MINOR__))
 519 #  if defined restrict || 199901L <= __STDC_VERSION__
 520 #   define __restrict restrict
 521 #  else
 522 #   define __restrict
 523 #  endif
 524 # endif
 525 #endif
 526 /* gcc 3.1 and up support the [restrict] syntax.  */
 527 #ifndef __restrict_arr
 528 # if (__GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 1)) \
 529      && !defined __GNUG__
 530 #  define __restrict_arr __restrict
 531 # else
 532 #  define __restrict_arr
 533 # endif
 534 #endif
 535
 536 /* POSIX compatibility.  */
 537 extern int regcomp (regex_t *__restrict __preg,
 538                     const char *__restrict __pattern,
 539                     int __cflags);
 540
 541 extern int regexec (const regex_t *__restrict __preg,
 542                     const char *__restrict __string, size_t __nmatch,
 543                     regmatch_t __pmatch[__restrict_arr],
 544                     int __eflags);
 545
 546 extern size_t regerror (int __errcode, const regex_t *__restrict __preg,
 547                         char *__restrict __errbuf, size_t __errbuf_size);
 548
 549 extern void regfree (regex_t *__preg);
 550
 551
 552 #ifdef __cplusplus
 553 }
 554 #endif  /* C++ */
 555
 556 #endif /* regex.h */