.TH "std::regex_constants" 3cxx "Sat Aug 14 2021" "libstdc++" \" -*- nroff -*-
.ad l
.nh
.SH NAME
std::regex_constants \- ISO C++-0x entities sub namespace for regex\&.  

.SH SYNOPSIS
.br
.PP
.SS "5\&.1 Regular Expression Syntax Options"

.in +1c
.ti -1c
.RI "enum \fB__syntax_option\fP { \fB_S_icase\fP, \fB_S_nosubs\fP, \fB_S_optimize\fP, \fB_S_collate\fP, \fB_S_ECMAScript\fP, \fB_S_basic\fP, \fB_S_extended\fP, \fB_S_awk\fP, \fB_S_grep\fP, \fB_S_egrep\fP, \fB_S_polynomial\fP, \fB_S_syntax_last\fP }"
.br
.RI "This is a bitmask type indicating how to interpret the regex\&. "
.ti -1c
.RI "enum \fBsyntax_option_type\fP : unsigned int "
.br
.RI "This is a bitmask type indicating how to interpret the regex\&. "
.ti -1c
.RI "constexpr _GLIBCXX17_INLINE \fBsyntax_option_type\fP \fBicase\fP"
.br
.ti -1c
.RI "constexpr _GLIBCXX17_INLINE \fBsyntax_option_type\fP \fBnosubs\fP"
.br
.ti -1c
.RI "constexpr _GLIBCXX17_INLINE \fBsyntax_option_type\fP \fBoptimize\fP"
.br
.ti -1c
.RI "constexpr _GLIBCXX17_INLINE \fBsyntax_option_type\fP \fBcollate\fP"
.br
.ti -1c
.RI "constexpr _GLIBCXX17_INLINE \fBsyntax_option_type\fP \fBECMAScript\fP"
.br
.ti -1c
.RI "constexpr _GLIBCXX17_INLINE \fBsyntax_option_type\fP \fBbasic\fP"
.br
.ti -1c
.RI "constexpr _GLIBCXX17_INLINE \fBsyntax_option_type\fP \fBextended\fP"
.br
.ti -1c
.RI "constexpr _GLIBCXX17_INLINE \fBsyntax_option_type\fP \fBawk\fP"
.br
.ti -1c
.RI "constexpr _GLIBCXX17_INLINE \fBsyntax_option_type\fP \fBgrep\fP"
.br
.ti -1c
.RI "constexpr _GLIBCXX17_INLINE \fBsyntax_option_type\fP \fBegrep\fP"
.br
.ti -1c
.RI "constexpr _GLIBCXX17_INLINE \fBsyntax_option_type\fP \fB__polynomial\fP"
.br
.ti -1c
.RI "constexpr \fBsyntax_option_type\fP \fBoperator&\fP (\fBsyntax_option_type\fP __a, \fBsyntax_option_type\fP __b)"
.br
.RI "This is a bitmask type indicating how to interpret the regex\&. "
.ti -1c
.RI "constexpr \fBsyntax_option_type\fP \fBoperator|\fP (\fBsyntax_option_type\fP __a, \fBsyntax_option_type\fP __b)"
.br
.RI "This is a bitmask type indicating how to interpret the regex\&. "
.ti -1c
.RI "constexpr \fBsyntax_option_type\fP \fBoperator^\fP (\fBsyntax_option_type\fP __a, \fBsyntax_option_type\fP __b)"
.br
.RI "This is a bitmask type indicating how to interpret the regex\&. "
.ti -1c
.RI "constexpr \fBsyntax_option_type\fP \fBoperator~\fP (\fBsyntax_option_type\fP __a)"
.br
.RI "This is a bitmask type indicating how to interpret the regex\&. "
.ti -1c
.RI "\fBsyntax_option_type\fP & \fBoperator&=\fP (\fBsyntax_option_type\fP &__a, \fBsyntax_option_type\fP __b)"
.br
.RI "This is a bitmask type indicating how to interpret the regex\&. "
.ti -1c
.RI "\fBsyntax_option_type\fP & \fBoperator|=\fP (\fBsyntax_option_type\fP &__a, \fBsyntax_option_type\fP __b)"
.br
.RI "This is a bitmask type indicating how to interpret the regex\&. "
.ti -1c
.RI "\fBsyntax_option_type\fP & \fBoperator^=\fP (\fBsyntax_option_type\fP &__a, \fBsyntax_option_type\fP __b)"
.br
.RI "This is a bitmask type indicating how to interpret the regex\&. "
.in -1c
.SS "5\&.2 Matching Rules"
Matching a regular expression against a sequence of characters [first, last) proceeds according to the rules of the grammar specified for the regular expression object, modified according to the effects listed below for any bitmask elements set\&. 
.in +1c
.ti -1c
.RI "enum \fB__match_flag\fP { \fB_S_not_bol\fP, \fB_S_not_eol\fP, \fB_S_not_bow\fP, \fB_S_not_eow\fP, \fB_S_any\fP, \fB_S_not_null\fP, \fB_S_continuous\fP, \fB_S_prev_avail\fP, \fB_S_sed\fP, \fB_S_no_copy\fP, \fB_S_first_only\fP, \fB_S_match_flag_last\fP }"
.br
.RI "This is a bitmask type indicating regex matching rules\&. "
.ti -1c
.RI "enum \fBmatch_flag_type\fP : unsigned int "
.br
.RI "This is a bitmask type indicating regex matching rules\&. "
.ti -1c
.RI "constexpr _GLIBCXX17_INLINE \fBmatch_flag_type\fP \fBmatch_default\fP"
.br
.ti -1c
.RI "constexpr _GLIBCXX17_INLINE \fBmatch_flag_type\fP \fBmatch_not_bol\fP"
.br
.ti -1c
.RI "constexpr _GLIBCXX17_INLINE \fBmatch_flag_type\fP \fBmatch_not_eol\fP"
.br
.ti -1c
.RI "constexpr _GLIBCXX17_INLINE \fBmatch_flag_type\fP \fBmatch_not_bow\fP"
.br
.ti -1c
.RI "constexpr _GLIBCXX17_INLINE \fBmatch_flag_type\fP \fBmatch_not_eow\fP"
.br
.ti -1c
.RI "constexpr _GLIBCXX17_INLINE \fBmatch_flag_type\fP \fBmatch_any\fP"
.br
.ti -1c
.RI "constexpr _GLIBCXX17_INLINE \fBmatch_flag_type\fP \fBmatch_not_null\fP"
.br
.ti -1c
.RI "constexpr _GLIBCXX17_INLINE \fBmatch_flag_type\fP \fBmatch_continuous\fP"
.br
.ti -1c
.RI "constexpr _GLIBCXX17_INLINE \fBmatch_flag_type\fP \fBmatch_prev_avail\fP"
.br
.ti -1c
.RI "constexpr _GLIBCXX17_INLINE \fBmatch_flag_type\fP \fBformat_default\fP"
.br
.ti -1c
.RI "constexpr _GLIBCXX17_INLINE \fBmatch_flag_type\fP \fBformat_sed\fP"
.br
.ti -1c
.RI "constexpr _GLIBCXX17_INLINE \fBmatch_flag_type\fP \fBformat_no_copy\fP"
.br
.ti -1c
.RI "constexpr _GLIBCXX17_INLINE \fBmatch_flag_type\fP \fBformat_first_only\fP"
.br
.ti -1c
.RI "constexpr \fBmatch_flag_type\fP \fBoperator&\fP (\fBmatch_flag_type\fP __a, \fBmatch_flag_type\fP __b)"
.br
.RI "This is a bitmask type indicating regex matching rules\&. "
.ti -1c
.RI "constexpr \fBmatch_flag_type\fP \fBoperator|\fP (\fBmatch_flag_type\fP __a, \fBmatch_flag_type\fP __b)"
.br
.RI "This is a bitmask type indicating regex matching rules\&. "
.ti -1c
.RI "constexpr \fBmatch_flag_type\fP \fBoperator^\fP (\fBmatch_flag_type\fP __a, \fBmatch_flag_type\fP __b)"
.br
.RI "This is a bitmask type indicating regex matching rules\&. "
.ti -1c
.RI "constexpr \fBmatch_flag_type\fP \fBoperator~\fP (\fBmatch_flag_type\fP __a)"
.br
.RI "This is a bitmask type indicating regex matching rules\&. "
.ti -1c
.RI "\fBmatch_flag_type\fP & \fBoperator&=\fP (\fBmatch_flag_type\fP &__a, \fBmatch_flag_type\fP __b)"
.br
.RI "This is a bitmask type indicating regex matching rules\&. "
.ti -1c
.RI "\fBmatch_flag_type\fP & \fBoperator|=\fP (\fBmatch_flag_type\fP &__a, \fBmatch_flag_type\fP __b)"
.br
.RI "This is a bitmask type indicating regex matching rules\&. "
.ti -1c
.RI "\fBmatch_flag_type\fP & \fBoperator^=\fP (\fBmatch_flag_type\fP &__a, \fBmatch_flag_type\fP __b)"
.br
.RI "This is a bitmask type indicating regex matching rules\&. "
.in -1c
.SS "5\&.3 Error Types"

.in +1c
.ti -1c
.RI "enum \fBerror_type\fP { \fB_S_error_collate\fP, \fB_S_error_ctype\fP, \fB_S_error_escape\fP, \fB_S_error_backref\fP, \fB_S_error_brack\fP, \fB_S_error_paren\fP, \fB_S_error_brace\fP, \fB_S_error_badbrace\fP, \fB_S_error_range\fP, \fB_S_error_space\fP, \fB_S_error_badrepeat\fP, \fB_S_error_complexity\fP, \fB_S_error_stack\fP }"
.br
.ti -1c
.RI "constexpr \fBerror_type\fP \fBerror_collate\fP (_S_error_collate)"
.br
.ti -1c
.RI "constexpr \fBerror_type\fP \fBerror_ctype\fP (_S_error_ctype)"
.br
.ti -1c
.RI "constexpr \fBerror_type\fP \fBerror_escape\fP (_S_error_escape)"
.br
.ti -1c
.RI "constexpr \fBerror_type\fP \fBerror_backref\fP (_S_error_backref)"
.br
.ti -1c
.RI "constexpr \fBerror_type\fP \fBerror_brack\fP (_S_error_brack)"
.br
.ti -1c
.RI "constexpr \fBerror_type\fP \fBerror_paren\fP (_S_error_paren)"
.br
.ti -1c
.RI "constexpr \fBerror_type\fP \fBerror_brace\fP (_S_error_brace)"
.br
.ti -1c
.RI "constexpr \fBerror_type\fP \fBerror_badbrace\fP (_S_error_badbrace)"
.br
.ti -1c
.RI "constexpr \fBerror_type\fP \fBerror_range\fP (_S_error_range)"
.br
.ti -1c
.RI "constexpr \fBerror_type\fP \fBerror_space\fP (_S_error_space)"
.br
.ti -1c
.RI "constexpr \fBerror_type\fP \fBerror_badrepeat\fP (_S_error_badrepeat)"
.br
.ti -1c
.RI "constexpr \fBerror_type\fP \fBerror_complexity\fP (_S_error_complexity)"
.br
.ti -1c
.RI "constexpr \fBerror_type\fP \fBerror_stack\fP (_S_error_stack)"
.br
.in -1c
.SH "Detailed Description"
.PP 
ISO C++-0x entities sub namespace for regex\&. 
.SH "Enumeration Type Documentation"
.PP 
.SS "enum \fBstd::regex_constants::__match_flag\fP"

.PP
This is a bitmask type indicating regex matching rules\&. The \fCmatch_flag_type\fP is implementation defined but it is valid to perform bitwise operations on these values and expect the right thing to happen\&. 
.PP
Definition at line 232 of file regex_constants\&.h\&.
.SS "enum \fBstd::regex_constants::__syntax_option\fP"

.PP
This is a bitmask type indicating how to interpret the regex\&. The \fCsyntax_option_type\fP is implementation defined but it is valid to perform bitwise operations on these values and expect the right thing to happen\&.
.PP
A valid value of type syntax_option_type shall have exactly one of the elements \fCECMAScript\fP, \fCbasic\fP, \fCextended\fP, \fCawk\fP, \fCgrep\fP, \fCegrep\fP set\&. 
.PP
Definition at line 54 of file regex_constants\&.h\&.
.SS "enum \fBstd::regex_constants::error_type\fP"
The expression contained an invalid collating element name\&. 
.PP
Definition at line 49 of file regex_error\&.h\&.
.SS "enum \fBstd::regex_constants::match_flag_type\fP : unsigned int"

.PP
This is a bitmask type indicating regex matching rules\&. The \fCmatch_flag_type\fP is implementation defined but it is valid to perform bitwise operations on these values and expect the right thing to happen\&. 
.PP
Definition at line 255 of file regex_constants\&.h\&.
.SS "enum \fBstd::regex_constants::syntax_option_type\fP : unsigned int"

.PP
This is a bitmask type indicating how to interpret the regex\&. The \fCsyntax_option_type\fP is implementation defined but it is valid to perform bitwise operations on these values and expect the right thing to happen\&.
.PP
A valid value of type syntax_option_type shall have exactly one of the elements \fCECMAScript\fP, \fCbasic\fP, \fCextended\fP, \fCawk\fP, \fCgrep\fP, \fCegrep\fP set\&. 
.PP
Definition at line 81 of file regex_constants\&.h\&.
.SH "Function Documentation"
.PP 
.SS "constexpr \fBerror_type\fP std::regex_constants::error_backref (_S_error_backref)\fC [constexpr]\fP"
The expression contained an invalid back reference\&. 
.SS "constexpr \fBerror_type\fP std::regex_constants::error_badbrace (_S_error_badbrace)\fC [constexpr]\fP"
The expression contained an invalid range in a {} expression\&. 
.SS "constexpr \fBerror_type\fP std::regex_constants::error_badrepeat (_S_error_badrepeat)\fC [constexpr]\fP"
One of \fI*?+{\fP was not preceded by a valid regular expression\&. 
.SS "constexpr \fBerror_type\fP std::regex_constants::error_brace (_S_error_brace)\fC [constexpr]\fP"
The expression contained mismatched { and } 
.SS "constexpr \fBerror_type\fP std::regex_constants::error_brack (_S_error_brack)\fC [constexpr]\fP"
The expression contained mismatched [ and ]\&. 
.SS "constexpr \fBerror_type\fP std::regex_constants::error_collate (_S_error_collate)\fC [constexpr]\fP"
The expression contained an invalid collating element name\&. 
.SS "constexpr \fBerror_type\fP std::regex_constants::error_complexity (_S_error_complexity)\fC [constexpr]\fP"
The complexity of an attempted match against a regular expression exceeded a pre-set level\&. 
.SS "constexpr \fBerror_type\fP std::regex_constants::error_ctype (_S_error_ctype)\fC [constexpr]\fP"
The expression contained an invalid character class name\&. 
.SS "constexpr \fBerror_type\fP std::regex_constants::error_escape (_S_error_escape)\fC [constexpr]\fP"
The expression contained an invalid escaped character, or a trailing escape\&. 
.SS "constexpr \fBerror_type\fP std::regex_constants::error_paren (_S_error_paren)\fC [constexpr]\fP"
The expression contained mismatched ( and )\&. 
.SS "constexpr \fBerror_type\fP std::regex_constants::error_range (_S_error_range)\fC [constexpr]\fP"
The expression contained an invalid character range, such as [b-a] in most encodings\&. 
.SS "constexpr \fBerror_type\fP std::regex_constants::error_space (_S_error_space)\fC [constexpr]\fP"
There was insufficient memory to convert the expression into a finite state machine\&. 
.SS "constexpr \fBerror_type\fP std::regex_constants::error_stack (_S_error_stack)\fC [constexpr]\fP"
There was insufficient memory to determine whether the regular expression could match the specified character sequence\&. 
.SS "constexpr \fBmatch_flag_type\fP std::regex_constants::operator& (\fBmatch_flag_type\fP __a, \fBmatch_flag_type\fP __b)\fC [inline]\fP, \fC [constexpr]\fP"

.PP
This is a bitmask type indicating regex matching rules\&. The \fCmatch_flag_type\fP is implementation defined but it is valid to perform bitwise operations on these values and expect the right thing to happen\&. 
.PP
Definition at line 374 of file regex_constants\&.h\&.
.SS "constexpr \fBsyntax_option_type\fP std::regex_constants::operator& (\fBsyntax_option_type\fP __a, \fBsyntax_option_type\fP __b)\fC [inline]\fP, \fC [constexpr]\fP"

.PP
This is a bitmask type indicating how to interpret the regex\&. The \fCsyntax_option_type\fP is implementation defined but it is valid to perform bitwise operations on these values and expect the right thing to happen\&.
.PP
A valid value of type syntax_option_type shall have exactly one of the elements \fCECMAScript\fP, \fCbasic\fP, \fCextended\fP, \fCawk\fP, \fCgrep\fP, \fCegrep\fP set\&. 
.PP
Definition at line 183 of file regex_constants\&.h\&.
.SS "\fBmatch_flag_type\fP& std::regex_constants::operator&= (\fBmatch_flag_type\fP & __a, \fBmatch_flag_type\fP __b)\fC [inline]\fP"

.PP
This is a bitmask type indicating regex matching rules\&. The \fCmatch_flag_type\fP is implementation defined but it is valid to perform bitwise operations on these values and expect the right thing to happen\&. 
.PP
Definition at line 399 of file regex_constants\&.h\&.
.SS "\fBsyntax_option_type\fP& std::regex_constants::operator&= (\fBsyntax_option_type\fP & __a, \fBsyntax_option_type\fP __b)\fC [inline]\fP"

.PP
This is a bitmask type indicating how to interpret the regex\&. The \fCsyntax_option_type\fP is implementation defined but it is valid to perform bitwise operations on these values and expect the right thing to happen\&.
.PP
A valid value of type syntax_option_type shall have exactly one of the elements \fCECMAScript\fP, \fCbasic\fP, \fCextended\fP, \fCawk\fP, \fCgrep\fP, \fCegrep\fP set\&. 
.PP
Definition at line 208 of file regex_constants\&.h\&.
.SS "constexpr \fBmatch_flag_type\fP std::regex_constants::operator^ (\fBmatch_flag_type\fP __a, \fBmatch_flag_type\fP __b)\fC [inline]\fP, \fC [constexpr]\fP"

.PP
This is a bitmask type indicating regex matching rules\&. The \fCmatch_flag_type\fP is implementation defined but it is valid to perform bitwise operations on these values and expect the right thing to happen\&. 
.PP
Definition at line 388 of file regex_constants\&.h\&.
.SS "constexpr \fBsyntax_option_type\fP std::regex_constants::operator^ (\fBsyntax_option_type\fP __a, \fBsyntax_option_type\fP __b)\fC [inline]\fP, \fC [constexpr]\fP"

.PP
This is a bitmask type indicating how to interpret the regex\&. The \fCsyntax_option_type\fP is implementation defined but it is valid to perform bitwise operations on these values and expect the right thing to happen\&.
.PP
A valid value of type syntax_option_type shall have exactly one of the elements \fCECMAScript\fP, \fCbasic\fP, \fCextended\fP, \fCawk\fP, \fCgrep\fP, \fCegrep\fP set\&. 
.PP
Definition at line 197 of file regex_constants\&.h\&.
.SS "\fBmatch_flag_type\fP& std::regex_constants::operator^= (\fBmatch_flag_type\fP & __a, \fBmatch_flag_type\fP __b)\fC [inline]\fP"

.PP
This is a bitmask type indicating regex matching rules\&. The \fCmatch_flag_type\fP is implementation defined but it is valid to perform bitwise operations on these values and expect the right thing to happen\&. 
.PP
Definition at line 407 of file regex_constants\&.h\&.
.SS "\fBsyntax_option_type\fP& std::regex_constants::operator^= (\fBsyntax_option_type\fP & __a, \fBsyntax_option_type\fP __b)\fC [inline]\fP"

.PP
This is a bitmask type indicating how to interpret the regex\&. The \fCsyntax_option_type\fP is implementation defined but it is valid to perform bitwise operations on these values and expect the right thing to happen\&.
.PP
A valid value of type syntax_option_type shall have exactly one of the elements \fCECMAScript\fP, \fCbasic\fP, \fCextended\fP, \fCawk\fP, \fCgrep\fP, \fCegrep\fP set\&. 
.PP
Definition at line 216 of file regex_constants\&.h\&.
.SS "constexpr \fBmatch_flag_type\fP std::regex_constants::operator| (\fBmatch_flag_type\fP __a, \fBmatch_flag_type\fP __b)\fC [inline]\fP, \fC [constexpr]\fP"

.PP
This is a bitmask type indicating regex matching rules\&. The \fCmatch_flag_type\fP is implementation defined but it is valid to perform bitwise operations on these values and expect the right thing to happen\&. 
.PP
Definition at line 381 of file regex_constants\&.h\&.
.SS "constexpr \fBsyntax_option_type\fP std::regex_constants::operator| (\fBsyntax_option_type\fP __a, \fBsyntax_option_type\fP __b)\fC [inline]\fP, \fC [constexpr]\fP"

.PP
This is a bitmask type indicating how to interpret the regex\&. The \fCsyntax_option_type\fP is implementation defined but it is valid to perform bitwise operations on these values and expect the right thing to happen\&.
.PP
A valid value of type syntax_option_type shall have exactly one of the elements \fCECMAScript\fP, \fCbasic\fP, \fCextended\fP, \fCawk\fP, \fCgrep\fP, \fCegrep\fP set\&. 
.PP
Definition at line 190 of file regex_constants\&.h\&.
.SS "\fBmatch_flag_type\fP& std::regex_constants::operator|= (\fBmatch_flag_type\fP & __a, \fBmatch_flag_type\fP __b)\fC [inline]\fP"

.PP
This is a bitmask type indicating regex matching rules\&. The \fCmatch_flag_type\fP is implementation defined but it is valid to perform bitwise operations on these values and expect the right thing to happen\&. 
.PP
Definition at line 403 of file regex_constants\&.h\&.
.SS "\fBsyntax_option_type\fP& std::regex_constants::operator|= (\fBsyntax_option_type\fP & __a, \fBsyntax_option_type\fP __b)\fC [inline]\fP"

.PP
This is a bitmask type indicating how to interpret the regex\&. The \fCsyntax_option_type\fP is implementation defined but it is valid to perform bitwise operations on these values and expect the right thing to happen\&.
.PP
A valid value of type syntax_option_type shall have exactly one of the elements \fCECMAScript\fP, \fCbasic\fP, \fCextended\fP, \fCawk\fP, \fCgrep\fP, \fCegrep\fP set\&. 
.PP
Definition at line 212 of file regex_constants\&.h\&.
.SS "constexpr \fBmatch_flag_type\fP std::regex_constants::operator~ (\fBmatch_flag_type\fP __a)\fC [inline]\fP, \fC [constexpr]\fP"

.PP
This is a bitmask type indicating regex matching rules\&. The \fCmatch_flag_type\fP is implementation defined but it is valid to perform bitwise operations on these values and expect the right thing to happen\&. 
.PP
Definition at line 395 of file regex_constants\&.h\&.
.SS "constexpr \fBsyntax_option_type\fP std::regex_constants::operator~ (\fBsyntax_option_type\fP __a)\fC [inline]\fP, \fC [constexpr]\fP"

.PP
This is a bitmask type indicating how to interpret the regex\&. The \fCsyntax_option_type\fP is implementation defined but it is valid to perform bitwise operations on these values and expect the right thing to happen\&.
.PP
A valid value of type syntax_option_type shall have exactly one of the elements \fCECMAScript\fP, \fCbasic\fP, \fCextended\fP, \fCawk\fP, \fCgrep\fP, \fCegrep\fP set\&. 
.PP
Definition at line 204 of file regex_constants\&.h\&.
.SH "Variable Documentation"
.PP 
.SS "constexpr _GLIBCXX17_INLINE \fBsyntax_option_type\fP std::regex_constants::__polynomial\fC [constexpr]\fP"
Extension: Ensure both space complexity of compiled regex and time complexity execution are not exponential\&. If specified in a regex with back-references, the exception regex_constants::error_complexity will be thrown\&. 
.PP
Definition at line 179 of file regex_constants\&.h\&.
.SS "constexpr _GLIBCXX17_INLINE \fBsyntax_option_type\fP std::regex_constants::awk\fC [constexpr]\fP"
Specifies that the grammar recognized by the regular expression engine is that used by POSIX utility awk in IEEE Std 1003\&.1-2001\&. This option is identical to syntax_option_type extended, except that C-style escape sequences are supported\&. These sequences are: \\\\, \\a, \\b, \\f, \\n, \\r, \\t , \\v, \\&apos,, &apos,, and \\ddd (where ddd is one, two, or three octal digits)\&. 
.PP
Definition at line 152 of file regex_constants\&.h\&.
.SS "constexpr _GLIBCXX17_INLINE \fBsyntax_option_type\fP std::regex_constants::basic\fC [constexpr]\fP"
Specifies that the grammar recognized by the regular expression engine is that used by POSIX basic regular expressions in IEEE Std 1003\&.1-2001, Portable Operating System Interface (POSIX), Base Definitions and Headers, Section 9, Regular Expressions [IEEE, Information Technology -- Portable Operating System Interface (POSIX), IEEE Standard 1003\&.1-2001]\&. 
.PP
Definition at line 132 of file regex_constants\&.h\&.
.SS "constexpr _GLIBCXX17_INLINE \fBsyntax_option_type\fP std::regex_constants::collate\fC [constexpr]\fP"
Specifies that character ranges of the form [a-b] should be locale sensitive\&. 
.PP
Definition at line 111 of file regex_constants\&.h\&.
.SS "constexpr _GLIBCXX17_INLINE \fBsyntax_option_type\fP std::regex_constants::ECMAScript\fC [constexpr]\fP"
Specifies that the grammar recognized by the regular expression engine is that used by ECMAScript in ECMA-262 [Ecma International, ECMAScript Language Specification, Standard Ecma-262, third edition, 1999], as modified in section [28\&.13]\&. This grammar is similar to that defined in the PERL scripting language but extended with elements found in the POSIX regular expression grammar\&. 
.PP
Definition at line 122 of file regex_constants\&.h\&.
.SS "constexpr _GLIBCXX17_INLINE \fBsyntax_option_type\fP std::regex_constants::egrep\fC [constexpr]\fP"
Specifies that the grammar recognized by the regular expression engine is that used by POSIX utility grep when given the -E option in IEEE Std 1003\&.1-2001\&. This option is identical to syntax_option_type extended, except that newlines are treated as whitespace\&. 
.PP
Definition at line 170 of file regex_constants\&.h\&.
.SS "constexpr _GLIBCXX17_INLINE \fBsyntax_option_type\fP std::regex_constants::extended\fC [constexpr]\fP"
Specifies that the grammar recognized by the regular expression engine is that used by POSIX extended regular expressions in IEEE Std 1003\&.1-2001, Portable Operating System Interface (POSIX), Base Definitions and Headers, Section 9, Regular Expressions\&. 
.PP
Definition at line 141 of file regex_constants\&.h\&.
.SS "constexpr _GLIBCXX17_INLINE \fBmatch_flag_type\fP std::regex_constants::format_default\fC [constexpr]\fP"
When a regular expression match is to be replaced by a new string, the new string is constructed using the rules used by the ECMAScript replace function in ECMA- 262 [Ecma International, ECMAScript Language Specification, Standard Ecma-262, third edition, 1999], part 15\&.5\&.4\&.11 String\&.prototype\&.replace\&. In addition, during search and replace operations all non-overlapping occurrences of the regular expression are located and replaced, and sections of the input that did not match the expression are copied unchanged to the output string\&.
.PP
Format strings (from ECMA-262 [15\&.5\&.4\&.11]): 
.PD 0

.IP "\(bu" 2
$$ The dollar-sign itself ($) 
.IP "\(bu" 2
$& The matched substring\&. 
.IP "\(bu" 2
$` The portion of \fIstring\fP that precedes the matched substring\&. This would be match_results::prefix()\&. 
.IP "\(bu" 2
$' The portion of \fIstring\fP that follows the matched substring\&. This would be match_results::suffix()\&. 
.IP "\(bu" 2
$n The nth capture, where n is in [1,9] and $n is not followed by a decimal digit\&. If n <= match_results::size() and the nth capture is undefined, use the empty string instead\&. If n > match_results::size(), the result is implementation-defined\&. 
.IP "\(bu" 2
$nn The nnth capture, where nn is a two-digit decimal number on [01, 99]\&. If nn <= match_results::size() and the nth capture is undefined, use the empty string instead\&. If nn > match_results::size(), the result is implementation-defined\&. 
.PP

.PP
Definition at line 346 of file regex_constants\&.h\&.
.SS "constexpr _GLIBCXX17_INLINE \fBmatch_flag_type\fP std::regex_constants::format_first_only\fC [constexpr]\fP"
When specified during a search and replace operation, only the first occurrence of the regular expression shall be replaced\&. 
.PP
Definition at line 370 of file regex_constants\&.h\&.
.PP
Referenced by std::regex_replace()\&.
.SS "constexpr _GLIBCXX17_INLINE \fBmatch_flag_type\fP std::regex_constants::format_no_copy\fC [constexpr]\fP"
During a search and replace operation, sections of the character container sequence being searched that do not match the regular expression shall not be copied to the output string\&. 
.PP
Definition at line 363 of file regex_constants\&.h\&.
.PP
Referenced by std::regex_replace()\&.
.SS "constexpr _GLIBCXX17_INLINE \fBmatch_flag_type\fP std::regex_constants::format_sed\fC [constexpr]\fP"
When a regular expression match is to be replaced by a new string, the new string is constructed using the rules used by the POSIX sed utility in IEEE Std 1003\&.1- 2001 [IEEE, Information Technology -- Portable Operating System Interface (POSIX), IEEE Standard 1003\&.1-2001]\&. 
.PP
Definition at line 355 of file regex_constants\&.h\&.
.SS "constexpr _GLIBCXX17_INLINE \fBsyntax_option_type\fP std::regex_constants::grep\fC [constexpr]\fP"
Specifies that the grammar recognized by the regular expression engine is that used by POSIX utility grep in IEEE Std 1003\&.1-2001\&. This option is identical to syntax_option_type basic, except that newlines are treated as whitespace\&. 
.PP
Definition at line 161 of file regex_constants\&.h\&.
.SS "constexpr _GLIBCXX17_INLINE \fBsyntax_option_type\fP std::regex_constants::icase\fC [constexpr]\fP"
Specifies that the matching of regular expressions against a character sequence shall be performed without regard to case\&. 
.PP
Definition at line 87 of file regex_constants\&.h\&.
.SS "constexpr _GLIBCXX17_INLINE \fBmatch_flag_type\fP std::regex_constants::match_any\fC [constexpr]\fP"
If more than one match is possible then any match is an acceptable result\&. 
.PP
Definition at line 297 of file regex_constants\&.h\&.
.SS "constexpr _GLIBCXX17_INLINE \fBmatch_flag_type\fP std::regex_constants::match_continuous\fC [constexpr]\fP"
The expression only matches a sub-sequence that begins at first \&. 
.PP
Definition at line 309 of file regex_constants\&.h\&.
.PP
Referenced by std::regex_iterator< _Bi_iter, _Ch_type, _Rx_traits >::operator++()\&.
.SS "constexpr _GLIBCXX17_INLINE \fBmatch_flag_type\fP std::regex_constants::match_default\fC [constexpr]\fP"
The default matching rules\&. 
.PP
Definition at line 260 of file regex_constants\&.h\&.
.SS "constexpr _GLIBCXX17_INLINE \fBmatch_flag_type\fP std::regex_constants::match_not_bol\fC [constexpr]\fP"
The first character in the sequence [first, last) is treated as though it is not at the beginning of a line, so the character (^) in the regular expression shall not match [first, first)\&. 
.PP
Definition at line 268 of file regex_constants\&.h\&.
.SS "constexpr _GLIBCXX17_INLINE \fBmatch_flag_type\fP std::regex_constants::match_not_bow\fC [constexpr]\fP"
The expression \\b is not matched against the sub-sequence [first,first)\&. 
.PP
Definition at line 283 of file regex_constants\&.h\&.
.SS "constexpr _GLIBCXX17_INLINE \fBmatch_flag_type\fP std::regex_constants::match_not_eol\fC [constexpr]\fP"
The last character in the sequence [first, last) is treated as though it is not at the end of a line, so the character ($) in the regular expression shall not match [last, last)\&. 
.PP
Definition at line 276 of file regex_constants\&.h\&.
.SS "constexpr _GLIBCXX17_INLINE \fBmatch_flag_type\fP std::regex_constants::match_not_eow\fC [constexpr]\fP"
The expression \\b should not be matched against the sub-sequence [last,last)\&. 
.PP
Definition at line 290 of file regex_constants\&.h\&.
.SS "constexpr _GLIBCXX17_INLINE \fBmatch_flag_type\fP std::regex_constants::match_not_null\fC [constexpr]\fP"
The expression does not match an empty sequence\&. 
.PP
Definition at line 303 of file regex_constants\&.h\&.
.PP
Referenced by std::regex_iterator< _Bi_iter, _Ch_type, _Rx_traits >::operator++()\&.
.SS "constexpr _GLIBCXX17_INLINE \fBmatch_flag_type\fP std::regex_constants::match_prev_avail\fC [constexpr]\fP"
--first is a valid iterator position\&. When this flag is set then the flags match_not_bol and match_not_bow are ignored by the regular expression algorithms 28\&.11 and iterators 28\&.12\&. 
.PP
Definition at line 317 of file regex_constants\&.h\&.
.SS "constexpr _GLIBCXX17_INLINE \fBsyntax_option_type\fP std::regex_constants::nosubs\fC [constexpr]\fP"
Specifies that when a regular expression is matched against a character container sequence, no sub-expression matches are to be stored in the supplied match_results structure\&. 
.PP
Definition at line 95 of file regex_constants\&.h\&.
.SS "constexpr _GLIBCXX17_INLINE \fBsyntax_option_type\fP std::regex_constants::optimize\fC [constexpr]\fP"
Specifies that the regular expression engine should pay more attention to the speed with which regular expressions are matched, and less to the speed with which regular expression objects are constructed\&. Otherwise it has no detectable effect on the program output\&. 
.PP
Definition at line 104 of file regex_constants\&.h\&.
.SH "Author"
.PP 
Generated automatically by Doxygen for libstdc++ from the source code\&.