std::sub_match(3)

NAME
std::sub_match - std::sub_match

Synopsis
   Defined in header <regex>
   template< class BidirIt > (since C++11)
   class sub_match;
   The class template std::sub_match is used by the regular expression engine to denote
   sequences of characters matched by marked sub-expressions. A match is a [begin, end)
   pair within the target range matched by the regular expression, but with additional
   observer functions to enhance code clarity.
   Only the default constructor is publicly accessible. Instances of std::sub_match are
   normally constructed and populated as a part of a std::match_results container
   during the processing of one of the regex algorithms.
   The member functions return defined default values unless the matched member is
   true.
   std::sub_match inherits from std::pair<BidirIt, BidirIt>, although it cannot be
   treated as a std::pair object because member functions such as assignment will not
   work as expected.

Type requirements
   -
   BidirIt must meet the requirements of LegacyBidirectionalIterator.

Specializations
   Several specializations for common character sequence types are provided:
   Defined in header <regex>
   Type Definition
   std::csub_match std::sub_match<const char*>
   std::wcsub_match std::sub_match<const wchar_t*>
   std::ssub_match std::sub_match<std::string::const_iterator>
   std::wssub_match std::sub_match<std::wstring::const_iterator>

Member types
   Member type Definition
   iterator BidirIt
   value_type std::iterator_traits<BidirIt>::value_type
   difference_type std::iterator_traits<BidirIt>::difference_type
   string_type std::basic_string<value_type>

Member objects
   bool matched Indicates if this match was successful
                (public member object) Inherited from std::pair
   BidirIt first Start of the match sequence.
                  (public member object)
   BidirIt second One-past-the-end of the match sequence.
                  (public member object)

Member functions
    This section is incomplete
    Reason: Apply LWG 3204, add the swap() member function
   constructor constructs the match object
                        (public member function)

Observers
   length returns the length of the match (if any)
                        (public member function)
   str converts to the underlying string type
   operator string_type (public member function)
   compare compares matched subsequence (if any)
                        (public member function)

Non-member functions
   operator==
   operator!=
   operator<
   operator<=
   operator>
   operator>= compares a sub_match with another sub_match, a string, or a
   operator<=> character
   (removed in C++20) (function template)
   (removed in C++20)
   (removed in C++20)
   (removed in C++20)
   (removed in C++20)
   (C++20)
   operator<< outputs the matched character subsequence
                      (function template)

See also
   regex_token_iterator iterates through the specified sub-expressions within all regex
   (C++11) matches in a given string or through unmatched substrings
                        (class template)

Category:
     * Todo with reason