#include <regex.h>

regex.h

includes: _regex.h, _bounds.h, _types.h, Availability.h, sys/_types/_size_t.h, sys/_types/_wchar_t.h

40 macros · 10 functions · 3 typedefs · 2 structs

typedefregoff_t

typedef __darwin_off_t regoff_t

structregex_t

size 32, align 8

int	re_magic
size_t	re_nsub	number of parenthesized subexpressions
const char *	re_endp	end pointer for REG_PEND
struct re_guts *	re_g	none of your business :-)

typedefregex_t

typedef struct regex_t regex_t;

structregmatch_t

size 16, align 8

regoff_t	rm_so	start of match
regoff_t	rm_eo	end of match

typedefregmatch_t

typedef struct regmatch_t regmatch_t;

macroREG_BASIC

**************** regcomp() flags ****************

#define REG_BASIC 0000

Basic regular expressions (synonym for 0)

macroREG_EXTENDED

#define REG_EXTENDED 0001

Extended regular expressions

macroREG_ICASE

#define REG_ICASE 0002

Compile ignoring upper/lower case

macroREG_NOSUB

#define REG_NOSUB 0004

Compile only reporting success/failure

macroREG_NEWLINE

#define REG_NEWLINE 0010

Compile for newline-sensitive matching

macroREG_NOSPEC

#define REG_NOSPEC 0020

Compile turning off all special characters

macroREG_LITERAL

#define REG_LITERAL REG_NOSPEC

macroREG_PEND

#define REG_PEND 0040

Use re_endp as end pointer

macroREG_MINIMAL

#define REG_MINIMAL 0100

Compile using minimal repetition

macroREG_UNGREEDY

#define REG_UNGREEDY REG_MINIMAL

macroREG_DUMP

#define REG_DUMP 0200

Unused

macroREG_ENHANCED

#define REG_ENHANCED 0400

Additional (non-POSIX) features

macroREG_ENOSYS

***************** regerror() flags *****************

#define REG_ENOSYS (-1)

Reserved

macroREG_NOMATCH

#define REG_NOMATCH 1

regexec() function failed to match

macroREG_BADPAT

#define REG_BADPAT 2

invalid regular expression

macroREG_ECOLLATE

#define REG_ECOLLATE 3

invalid collating element

macroREG_ECTYPE

#define REG_ECTYPE 4

invalid character class

macroREG_EESCAPE

#define REG_EESCAPE 5

trailing backslash (\)

macroREG_ESUBREG

#define REG_ESUBREG 6

invalid backreference number

macroREG_EBRACK

#define REG_EBRACK 7

brackets ([ ]) not balanced

macroREG_EPAREN

#define REG_EPAREN 8

parentheses not balanced

macroREG_EBRACE

#define REG_EBRACE 9

braces not balanced

macroREG_BADBR

#define REG_BADBR 10

invalid repetition count(s)

macroREG_ERANGE

#define REG_ERANGE 11

invalid character range

macroREG_ESPACE

#define REG_ESPACE 12

out of memory

macroREG_BADRPT

#define REG_BADRPT 13

repetition-operator operand invalid

macroREG_EMPTY

#define REG_EMPTY 14

Unused

macroREG_ASSERT

#define REG_ASSERT 15

Unused

macroREG_INVARG

#define REG_INVARG 16

invalid argument to regex routine

macroREG_ILLSEQ

#define REG_ILLSEQ 17

illegal byte sequence

macroREG_BADMAX

#define REG_BADMAX 18

maximum repetition exceeds RE_DUP_MAX

macroREG_ATOI

#define REG_ATOI 255

convert name to number (!)

macroREG_ITOA

#define REG_ITOA 0400

convert number to name (!)

macroREG_NOTBOL

**************** regexec() flags ****************

#define REG_NOTBOL 00001

First character not at beginning of line

macroREG_NOTEOL

#define REG_NOTEOL 00002

Last character not at end of line

macroREG_STARTEND

#define REG_STARTEND 00004

String start/end in pmatch[0]

macroREG_TRACE

#define REG_TRACE 00400

Unused

macroREG_LARGE

#define REG_LARGE 01000

Unused

macroREG_BACKR

#define REG_BACKR 02000

force use of backref code

macroREG_BACKTRACKING_MATCHER

#define REG_BACKTRACKING_MATCHER REG_BACKR

functionregcomp

__DARWIN_ALIAS(regcomp)
int regcomp(regex_t * __restrict, const char * __restrict, int)

man page · July 11, 2025

regcomp(3) — regular-expression library

functionregerror

__cold
size_t regerror(
	int,
	const regex_t * __restrict,
	char *_LIBC_COUNT(__errbuf_size) __restrict,
	size_t __errbuf_size
)

man page · July 11, 2025

regerror(3) — regular-expression library

functionregexec

int regexec(
	const regex_t * __restrict,
	const char * __restrict,
	size_t __nmatch,
	regmatch_t __pmatch[ __restrict _LIBC_COUNT(__nmatch)],
	int
)

gcc under c99 mode won't compile "[ __restrict]" by itself. As a workaround, a dummy argument name is added.

man page · July 11, 2025

regexec(3) — regular-expression library

functionregfree

void regfree(regex_t *)

man page · July 11, 2025

regfree(3) — regular-expression library

functionregncomp

__OSX_AVAILABLE_STARTING(__MAC_10_8, __IPHONE_6_0)
int regncomp(
	regex_t * __restrict,
	const char *_LIBC_COUNT(__len) __restrict,
	size_t __len,
	int
)

Darwin extensions

man page · July 11, 2025

regncomp(3) — regular-expression library

functionregnexec

__OSX_AVAILABLE_STARTING(__MAC_10_8, __IPHONE_6_0)
int regnexec(
	const regex_t * __restrict,
	const char *_LIBC_COUNT(__len) __restrict,
	size_t __len,
	size_t __nmatch,
	regmatch_t __pmatch[ __restrict _LIBC_COUNT(__nmatch)],
	int
)

man page · July 11, 2025

regnexec(3) — regular-expression library

functionregwcomp

__OSX_AVAILABLE_STARTING(__MAC_10_8, __IPHONE_6_0)
int regwcomp(regex_t * __restrict, const wchar_t * __restrict, int)

man page · July 11, 2025

regwcomp(3) — regular-expression library

functionregwexec

__OSX_AVAILABLE_STARTING(__MAC_10_8, __IPHONE_6_0)
int regwexec(
	const regex_t * __restrict,
	const wchar_t * __restrict,
	size_t __nmatch,
	regmatch_t __pmatch[ __restrict _LIBC_COUNT(__nmatch)],
	int
)

man page · July 11, 2025

regwexec(3) — regular-expression library

functionregwncomp

__OSX_AVAILABLE_STARTING(__MAC_10_8, __IPHONE_6_0)
int regwncomp(
	regex_t * __restrict,
	const wchar_t * _LIBC_COUNT(__len) __restrict,
	size_t __len,
	int
)

functionregwnexec

__OSX_AVAILABLE_STARTING(__MAC_10_8, __IPHONE_6_0)
int regwnexec(
	const regex_t * __restrict,
	const wchar_t * _LIBC_COUNT(__len) __restrict,
	size_t __len,
	size_t __nmatch,
	regmatch_t __pmatch[ __restrict _LIBC_COUNT(__nmatch)],
	int
)