32 Regular expressions library [re]

32.8 Class template sub_­match [re.submatch]

32.8.1 General [re.submatch.general]

Class template sub_­match denotes the sequence of characters matched by a particular marked sub-expression.
namespace std { template<class BidirectionalIterator> class sub_match : public pair<BidirectionalIterator, BidirectionalIterator> { public: using value_type = typename iterator_traits<BidirectionalIterator>::value_type; using difference_type = typename iterator_traits<BidirectionalIterator>::difference_type; using iterator = BidirectionalIterator; using string_type = basic_string<value_type>; bool matched; constexpr sub_match(); difference_type length() const; operator string_type() const; string_type str() const; int compare(const sub_match& s) const; int compare(const string_type& s) const; int compare(const value_type* s) const; }; }

32.8.2 Members [re.submatch.members]

constexpr sub_match();
Effects: Value-initializes the pair base class subobject and the member matched.
difference_type length() const;
Returns: matched ? distance(first, second) : 0.
operator string_type() const;
Returns: matched ? string_­type(first, second) : string_­type().
string_type str() const;
Returns: matched ? string_­type(first, second) : string_­type().
int compare(const sub_match& s) const;
Returns: str().compare(s.str()).
int compare(const string_type& s) const;
Returns: str().compare(s).
int compare(const value_type* s) const;
Returns: str().compare(s).

32.8.3 Non-member operators [re.submatch.op]

Let SM-CAT(I) be compare_three_way_result_t<basic_string<typename iterator_traits<I>::value_type>>
template<class BiIter> bool operator==(const sub_match<BiIter>& lhs, const sub_match<BiIter>& rhs);
Returns: lhs.compare(rhs) == 0.
template<class BiIter> auto operator<=>(const sub_match<BiIter>& lhs, const sub_match<BiIter>& rhs);
Returns: static_­cast<SM-CAT(BiIter)>(lhs.compare(rhs) <=> 0).
template<class BiIter, class ST, class SA> bool operator==( const sub_match<BiIter>& lhs, const basic_string<typename iterator_traits<BiIter>::value_type, ST, SA>& rhs);
Returns: lhs.compare(typename sub_match<BiIter>::string_type(rhs.data(), rhs.size())) == 0
template<class BiIter, class ST, class SA> auto operator<=>( const sub_match<BiIter>& lhs, const basic_string<typename iterator_traits<BiIter>::value_type, ST, SA>& rhs);
Returns: static_cast<SM-CAT(BiIter)>(lhs.compare( typename sub_match<BiIter>::string_type(rhs.data(), rhs.size())) <=> 0 )
template<class BiIter> bool operator==(const sub_match<BiIter>& lhs, const typename iterator_traits<BiIter>::value_type* rhs);
Returns: lhs.compare(rhs) == 0.
template<class BiIter> auto operator<=>(const sub_match<BiIter>& lhs, const typename iterator_traits<BiIter>::value_type* rhs);
Returns: static_­cast<SM-CAT(BiIter)>(lhs.compare(rhs) <=> 0).
template<class BiIter> bool operator==(const sub_match<BiIter>& lhs, const typename iterator_traits<BiIter>::value_type& rhs);
Returns: lhs.compare(typename sub_­match<BiIter>​::​string_­type(1, rhs)) == 0.
template<class BiIter> auto operator<=>(const sub_match<BiIter>& lhs, const typename iterator_traits<BiIter>::value_type& rhs);
Returns: static_cast<SM-CAT(BiIter)>(lhs.compare( typename sub_match<BiIter>::string_type(1, rhs)) <=> 0 )
template<class charT, class ST, class BiIter> basic_ostream<charT, ST>& operator<<(basic_ostream<charT, ST>& os, const sub_match<BiIter>& m);
Returns: os << m.str().