regex.h(0P) POSIX Programmer's Manual regex.h(0P)
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This manual page is part of the POSIX Programmer's Manual. The Linux
implementation of this interface may differ (consult the corresponding
Linux manual page for details of Linux behavior), or the interface may
not be implemented on Linux.
NAME
regex.h -- regular expression matching types
SYNOPSIS
#include <regex.h>
DESCRIPTION
The <regex.h> header shall define the structures and symbolic constants
used by the regcomp(), regexec(), regerror(), and regfree() functions.
The <regex.h> header shall define the regex_t structure type, which
shall include at least the following member:
size_t re_nsub Number of parenthesized subexpressions.
The <regex.h> header shall define the size_t type as described in
<sys/types.h>.
The <regex.h> header shall define the regoff_t type as a signed integer
type that can hold the largest value that can be stored in either a
ptrdiff_t type or a ssize_t type.
The <regex.h> header shall define the regmatch_t structure type, which
shall include at least the following members:
regoff_t rm_so Byte offset from start of string
to start of substring.
regoff_t rm_eo Byte offset from start of string of the
first character after the end of substring.
The <regex.h> header shall define the following symbolic constants for
the cflags parameter to the regcomp() function:
REG_EXTENDED Use Extended Regular Expressions.
REG_ICASE Ignore case in match.
REG_NOSUB Report only success or fail in regexec().
REG_NEWLINE Change the handling of <newline>.
The <regex.h> header shall define the following symbolic constants for
the eflags parameter to the regexec() function:
REG_NOTBOL The <circumflex> character ('^'), when taken as a special
character, does not match the beginning of string.
REG_NOTEOL The <dollar-sign> ('$'), when taken as a special charac-
ter, does not match the end of string.
The <regex.h> header shall define the following symbolic constants as
error return values:
REG_NOMATCH regexec() failed to match.
REG_BADPAT Invalid regular expression.
REG_ECOLLATE Invalid collating element referenced.
REG_ECTYPE Invalid character class type referenced.
REG_EESCAPE Trailing <backslash> character in pattern.
REG_ESUBREG Number in \digit invalid or in error.
REG_EBRACK "[]" imbalance.
REG_EPAREN "\(\)" or "()" imbalance.
REG_EBRACE "\{\}" imbalance.
REG_BADBR Content of "\{\}" invalid: not a number, number too
large, more than two numbers, first larger than second.
REG_ERANGE Invalid endpoint in range expression.
REG_ESPACE Out of memory.
REG_BADRPT '?', '*', or '+' not preceded by valid regular expres-
sion.
The following shall be declared as functions and may also be defined as
macros. Function prototypes shall be provided.
int regcomp(regex_t *restrict, const char *restrict, int);
size_t regerror(int, const regex_t *restrict, char *restrict, size_t);
int regexec(const regex_t *restrict, const char *restrict, size_t,
regmatch_t [restrict], int);
void regfree(regex_t *);
The implementation may define additional macros or constants using
names beginning with REG_.
The following sections are informative.
APPLICATION USAGE
None.
RATIONALE
None.
FUTURE DIRECTIONS
None.
SEE ALSO
<sys_types.h>
The System Interfaces volume of POSIX.1-2008, regcomp()
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 7, Copyright (C) 2013 by the Institute of Electri-
cal and Electronics Engineers, Inc and The Open Group. (This is
POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) In the
event of any discrepancy between this version and the original IEEE and
The Open Group Standard, the original IEEE and The Open Group Standard
is the referee document. The original Standard can be obtained online
at http://www.unix.org/online.html .
Any typographical or formatting errors that appear in this page are
most likely to have been introduced during the conversion of the source
files to man page format. To report such errors, see https://www.ker-
nel.org/doc/man-pages/reporting_bugs.html .
IEEE/The Open Group 2013 regex.h(0P)