1regex.h(0P)                POSIX Programmer's Manual               regex.h(0P)
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PROLOG

6       This  manual  page is part of the POSIX Programmer's Manual.  The Linux
7       implementation of this interface may differ (consult the  corresponding
8       Linux  manual page for details of Linux behavior), or the interface may
9       not be implemented on Linux.
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11

NAME

13       regex.h — regular expression matching types
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SYNOPSIS

16       #include <regex.h>
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DESCRIPTION

19       The <regex.h> header shall define the structures and symbolic constants
20       used by the regcomp(), regexec(), regerror(), and regfree() functions.
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22       The  <regex.h>  header  shall  define the regex_t structure type, which
23       shall include at least the following member:
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25           size_t    re_nsub    Number of parenthesized subexpressions.
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27       The <regex.h> header shall define  the  size_t  type  as  described  in
28       <sys/types.h>.
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30       The <regex.h> header shall define the regoff_t type as a signed integer
31       type that can hold the largest value that can be  stored  in  either  a
32       ptrdiff_t type or a ssize_t type.
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34       The  <regex.h> header shall define the regmatch_t structure type, which
35       shall include at least the following members:
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37           regoff_t    rm_so    Byte offset from start of string
38                                to start of substring.
39           regoff_t    rm_eo    Byte offset from start of string of the
40                                first character after the end of substring.
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42       The <regex.h> header shall define the following symbolic constants  for
43       the cflags parameter to the regcomp() function:
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45       REG_EXTENDED  Use Extended Regular Expressions.
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47       REG_ICASE     Ignore case in match.
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49       REG_NOSUB     Report only success or fail in regexec().
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51       REG_NEWLINE   Change the handling of <newline>.
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53       The  <regex.h> header shall define the following symbolic constants for
54       the eflags parameter to the regexec() function:
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56       REG_NOTBOL    The <circumflex> character ('^'), when taken as a special
57                     character, does not match the beginning of string.
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59       REG_NOTEOL    The  <dollar-sign> ('$'), when taken as a special charac‐
60                     ter, does not match the end of string.
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62       The <regex.h> header shall define the following symbolic  constants  as
63       error return values:
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65       REG_NOMATCH   regexec() failed to match.
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67       REG_BADPAT    Invalid regular expression.
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69       REG_ECOLLATE  Invalid collating element referenced.
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71       REG_ECTYPE    Invalid character class type referenced.
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73       REG_EESCAPE   Trailing <backslash> character in pattern.
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75       REG_ESUBREG   Number in \digit invalid or in error.
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77       REG_EBRACK    "[]" imbalance.
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79       REG_EPAREN    "\(\)" or "()" imbalance.
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81       REG_EBRACE    "\{\}" imbalance.
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83       REG_BADBR     Content  of  "\{\}"  invalid:  not  a  number, number too
84                     large, more than two numbers, first larger than second.
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86       REG_ERANGE    Invalid endpoint in range expression.
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88       REG_ESPACE    Out of memory.
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90       REG_BADRPT    '?', '*', or '+' not preceded by  valid  regular  expres‐
91                     sion.
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93       The following shall be declared as functions and may also be defined as
94       macros. Function prototypes shall be provided.
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96           int    regcomp(regex_t *restrict, const char *restrict, int);
97           size_t regerror(int, const regex_t *restrict, char *restrict, size_t);
98           int    regexec(const regex_t *restrict, const char *restrict, size_t,
99                      regmatch_t [restrict], int);
100           void   regfree(regex_t *);
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102       The implementation may define  additional  macros  or  constants  using
103       names beginning with REG_.
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105       The following sections are informative.
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APPLICATION USAGE

108       None.
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RATIONALE

111       None.
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FUTURE DIRECTIONS

114       None.
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SEE ALSO

117       <sys_types.h>
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119       The System Interfaces volume of POSIX.1‐2008, regcomp()
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122       Portions  of  this text are reprinted and reproduced in electronic form
123       from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
124       --  Portable  Operating  System  Interface (POSIX), The Open Group Base
125       Specifications Issue 7, Copyright (C) 2013 by the Institute of Electri‐
126       cal  and  Electronics  Engineers,  Inc  and  The  Open Group.  (This is
127       POSIX.1-2008 with the 2013 Technical Corrigendum  1  applied.)  In  the
128       event of any discrepancy between this version and the original IEEE and
129       The Open Group Standard, the original IEEE and The Open Group  Standard
130       is  the  referee document. The original Standard can be obtained online
131       at http://www.unix.org/online.html .
132
133       Any typographical or formatting errors that appear  in  this  page  are
134       most likely to have been introduced during the conversion of the source
135       files to man page format. To report such errors,  see  https://www.ker‐
136       nel.org/doc/man-pages/reporting_bugs.html .
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140IEEE/The Open Group                  2013                          regex.h(0P)
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