operator==,!=,<,<=,>,>=,<=>(std::sub_match)

 

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Regular expressions library

Classes

basic_regex (C++11)

sub_match (C++11)

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regex_match (C++11)

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std::sub_match

Member functions

sub_match::sub_match

sub_match::length

sub_match::strsub_match::operator string_type

sub_match::compare

Non-member functions

operator==operator!=operator<<operator<=operator>operator>=operator<=> (until C++20)(until C++20)(until C++20)(until C++20)(until C++20)(C++20)

operator<<

 

Defined in header <regex>
Direct comparison
template< class BidirIt > bool operator==( const std::sub_match<BidirIt>& lhs,                  const std::sub_match<BidirIt>& rhs );	(1)	(since C++11)
template< class BidirIt > bool operator!=( const std::sub_match<BidirIt>& lhs,                  const std::sub_match<BidirIt>& rhs );	(2)	(since C++11) (until C++20)
template< class BidirIt > bool operator<( const std::sub_match<BidirIt>& lhs,                 const std::sub_match<BidirIt>& rhs );	(3)	(since C++11) (until C++20)
template< class BidirIt > bool operator<=( const std::sub_match<BidirIt>& lhs,                  const std::sub_match<BidirIt>& rhs );	(4)	(since C++11) (until C++20)
template< class BidirIt > bool operator>( const std::sub_match<BidirIt>& lhs,                 const std::sub_match<BidirIt>& rhs );	(5)	(since C++11) (until C++20)
template< class BidirIt > bool operator>=( const std::sub_match<BidirIt>& lhs,                  const std::sub_match<BidirIt>& rhs );	(6)	(since C++11) (until C++20)
template< class BidirIt > /*comp-cat*/ operator<=>( const std::sub_match<BidirIt>& lhs,                           const std::sub_match<BidirIt>& rhs );	(7)	(since C++20)
std::sub_match and std::basic_string
template< class BidirIt, class Traits, class Alloc > bool operator==( const std::sub_match<BidirIt>& sm,                  const std::basic_string<                      typename std::iterator_traits<BidirIt>::value_type,                      Traits,Alloc>& rhs );	(8)	(since C++11)
template< class BidirIt, class Traits, class Alloc > bool operator!=( const std::sub_match<BidirIt>& sm,                  const std::basic_string<                      typename std::iterator_traits<BidirIt>::value_type,                      Traits,Alloc>& st );	(9)	(since C++11) (until C++20)
template< class BidirIt, class Traits, class Alloc > bool operator<( const std::sub_match<BidirIt>& sm,                 const std::basic_string<                     typename std::iterator_traits<BidirIt>::value_type,                     Traits,Alloc>& st );	(10)	(since C++11) (until C++20)
template< class BidirIt, class Traits, class Alloc > bool operator<=( const std::sub_match<BidirIt>& sm,                  const std::basic_string<                      typename std::iterator_traits<BidirIt>::value_type,                      Traits,Alloc>& st );	(11)	(since C++11) (until C++20)
template< class BidirIt, class Traits, class Alloc > bool operator>( const std::sub_match<BidirIt>& sm,                 const std::basic_string<                     typename std::iterator_traits<BidirIt>::value_type,                     Traits,Alloc>& st );	(12)	(since C++11) (until C++20)
template< class BidirIt, class Traits, class Alloc > bool operator>=( const std::sub_match<BidirIt>& sm,                  const std::basic_string<                      typename std::iterator_traits<BidirIt>::value_type,                      Traits,Alloc>& st );	(13)	(since C++11) (until C++20)
template< class BidirIt, class Traits, class Alloc > /*comp-cat*/ operator<=>( const std::sub_match<BidirIt>& sm,                           const std::basic_string<                               typename std::iterator_traits<BidirIt>::value_type,                               Traits,Alloc>& st );	(14)	(since C++20)
std::basic_string and std::sub_match
template< class BidirIt, class Traits, class Alloc > bool operator==( const std::basic_string<                      typename std::iterator_traits<BidirIt>::value_type,                      Traits,Alloc>& st,                  const std::sub_match<BidirIt>& sm );	(15)	(since C++11) (until C++20)
template< class BidirIt, class Traits, class Alloc > bool operator!=( const std::basic_string<                      typename std::iterator_traits<BidirIt>::value_type,                      Traits,Alloc>& st,                  const std::sub_match<BidirIt>& sm );	(16)	(since C++11) (until C++20)
template< class BidirIt, class Traits, class Alloc > bool operator<( const std::basic_string<                     typename std::iterator_traits<BidirIt>::value_type,                     Traits,Alloc>& st,                 const std::sub_match<BidirIt>& sm );	(17)	(since C++11) (until C++20)
template< class BidirIt, class Traits, class Alloc > bool operator<=( const std::basic_string<                     typename std::iterator_traits<BidirIt>::value_type,                     Traits,Alloc>& st,                 const std::sub_match<BidirIt>& sm );	(18)	(since C++11) (until C++20)
template< class BidirIt, class Traits, class Alloc > bool operator>( const std::basic_string<                     typename std::iterator_traits<BidirIt>::value_type,                     Traits,Alloc>& st,                 const std::sub_match<BidirIt>& sm );	(19)	(since C++11) (until C++20)
template< class BidirIt, class Traits, class Alloc > bool operator>=( const std::basic_string<                      typename std::iterator_traits<BidirIt>::value_type,                      Traits,Alloc>& st,                  const std::sub_match<BidirIt>& sm );	(20)	(since C++11) (until C++20)
std::sub_match and std::iterator_traits<BidirIt>::value_type*
template< class BidirIt > bool operator==( const std::sub_match<BidirIt>& sm,                  const typename std::iterator_traits<BidirIt>::value_type* s );	(21)	(since C++11)
template< class BidirIt > bool operator!=( const std::sub_match<BidirIt>& sm,                  const typename std::iterator_traits<BidirIt>::value_type* s );	(22)	(since C++11) (until C++20)
template< class BidirIt > bool operator<( const std::sub_match<BidirIt>& sm,                 const typename std::iterator_traits<BidirIt>::value_type* s );	(23)	(since C++11) (until C++20)
template< class BidirIt > bool operator<=( const std::sub_match<BidirIt>& sm,                  const typename std::iterator_traits<BidirIt>::value_type* s );	(24)	(since C++11) (until C++20)
template< class BidirIt > bool operator>( const std::sub_match<BidirIt>& sm,                 const typename std::iterator_traits<BidirIt>::value_type* s );	(25)	(since C++11) (until C++20)
template< class BidirIt > bool operator>=( const std::sub_match<BidirIt>& sm,                  const typename std::iterator_traits<BidirIt>::value_type* s );	(26)	(since C++11) (until C++20)
template< class BidirIt > /*comp-cat*/ operator<=>( const std::sub_match<BidirIt>& sm,                           const typename std::iterator_traits<BidirIt>::value_type* s );	(27)	(since C++20)
std::iterator_traits<BidirIt>::value_type* and std::sub_match
template< class BidirIt > bool operator==( const typename std::iterator_traits<BidirIt>::value_type* s,                  const std::sub_match<BidirIt>& sm );	(28)	(since C++11) (until C++20)
template< class BidirIt > bool operator!=( const typename std::iterator_traits<BidirIt>::value_type* s,                  const std::sub_match<BidirIt>& sm );	(29)	(since C++11) (until C++20)
template< class BidirIt > bool operator<( const typename std::iterator_traits<BidirIt>::value_type* s,                 const std::sub_match<BidirIt>& sm );	(30)	(since C++11) (until C++20)
template< class BidirIt > bool operator<=( const typename std::iterator_traits<BidirIt>::value_type* s,                  const std::sub_match<BidirIt>& sm );	(31)	(since C++11) (until C++20)
template< class BidirIt > bool operator>( const typename std::iterator_traits<BidirIt>::value_type* s,                 const std::sub_match<BidirIt>& sm );	(32)	(since C++11) (until C++20)
template< class BidirIt > bool operator>=( const typename std::iterator_traits<BidirIt>::value_type* s,                  const std::sub_match<BidirIt>& sm );	(33)	(since C++11) (until C++20)
std::sub_match and std::iterator_traits<BidirIt>::value_type
template< class BidirIt > bool operator==( const std::sub_match<BidirIt>& sm,                  const typename std::iterator_traits<BidirIt>::value_type& ch );	(34)	(since C++11)
template< class BidirIt > bool operator!=( const std::sub_match<BidirIt>& sm,                  const typename std::iterator_traits<BidirIt>::value_type& ch );	(35)	(since C++11) (until C++20)
template< class BidirIt > bool operator<( const std::sub_match<BidirIt>& sm,                 const typename std::iterator_traits<BidirIt>::value_type& ch );	(36)	(since C++11) (until C++20)
template< class BidirIt > bool operator<=( const std::sub_match<BidirIt>& sm,                  const typename std::iterator_traits<BidirIt>::value_type& ch );	(37)	(since C++11) (until C++20)
template< class BidirIt > bool operator>( const std::sub_match<BidirIt>& sm,                 const typename std::iterator_traits<BidirIt>::value_type& ch );	(38)	(since C++11) (until C++20)
template< class BidirIt > bool operator>=( const std::sub_match<BidirIt>& sm,                  const typename std::iterator_traits<BidirIt>::value_type& ch );	(39)	(since C++11) (until C++20)
template< class BidirIt > /*comp-cat*/ operator<=>( const std::sub_match<BidirIt>& sm,                           const typename std::iterator_traits<BidirIt>::value_type& ch );	(40)	(since C++20)
std::iterator_traits<BidirIt>::value_type and std::sub_match
template< class BidirIt > bool operator==( const typename std::iterator_traits<BidirIt>::value_type& ch,                  const std::sub_match<BidirIt>& sm );	(41)	(since C++11) (until C++20)
template< class BidirIt > bool operator!=( const typename std::iterator_traits<BidirIt>::value_type& ch,                  const std::sub_match<BidirIt>& sm );	(42)	(since C++11) (until C++20)
template< class BidirIt > bool operator<( const typename std::iterator_traits<BidirIt>::value_type& ch,                 const std::sub_match<BidirIt>& sm );	(43)	(since C++11) (until C++20)
template< class BidirIt > bool operator<=( const typename std::iterator_traits<BidirIt>::value_type& ch,                  const std::sub_match<BidirIt>& sm );	(44)	(since C++11) (until C++20)
template< class BidirIt > bool operator>( const typename std::iterator_traits<BidirIt>::value_type& ch,                 const std::sub_match<BidirIt>& sm );	(45)	(since C++11) (until C++20)
template< class BidirIt > bool operator>=( const typename std::iterator_traits<BidirIt>::value_type& ch,                  const std::sub_match<BidirIt>& sm );	(46)	(since C++11) (until C++20)

Compares a sub_match to another sub_match, a string, a null-terminated character sequence or a character.

1-7) Compares two sub_match directly by comparing their underlying character sequences. Implemented as if by lhs.compare(rhs)

8-20) Compares a sub_match with a std::basic_string. Implemented as if by sm.compare(typename sub_match<BidirIt>::string_type(st.data(), st.size()).

21-33) Compares a sub_match with a null-terminated string. Implemented as if by sm.compare(s).

34-46) Compares a sub_match with a character. Implemented as if by sm.compare(typename sub_match<BidirIt>::string_type(1, ch)).

The return type of three-way comparison operators (/*comp-cat*/) is std::compare_three_way_result_t<typename std::sub_match<BidirIt>::string_type>>, i.e. std::char_traits<typename std::iterator_traits<BidirIt>::value_type>::comparison_category if that qualified-id is valid and denotes a type, std::weak_ordering otherwise. If /*comp-cat*/ is not a comparison category type, the program is ill-formed. The <, <=, >, >=, and != operators are synthesized from operator<=> and operator== respectively.

(since C++20)

Parameters

lhs, rhs, sm	-	a sub_match to compare
st	-	a basic_string to compare
s	-	a pointer to a null-terminated string to compare
ch	-	a character to compare

Return value

For operator==, (since C++20)true if the corresponding comparison holds as defined by std::sub_match::compare(), false otherwise.

For operator<=>, static_cast</*comp-cat*/>(/*comp-res*/ <=> 0), where /*comp-res*/ is the result of std::sub_match::compare() described above.

(since C++20)

Notes

If value type of BidirIt is char, wchar_t, char8_t, char16_t, or char32_t, the return type of operator<=> is std::strong_ordering.

(since C++20)

Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

DR	Applied to	Behavior as published	Correct behavior
LWG 3432	C++20	the return type of operator<=> was not required to be a comparison category type	required

See also

compare

compares matched subsequence (if any) (public member function)