< cpp‎ | regex
Defined in header <regex>

    class BidirIt,
    class Alloc = std::allocator<std::sub_match<BidirIt>>

> class match_results;
(since C++11)

The class template std::match_results holds a collection of character sequences that represent the result of a regular expression match.

This is a specialized allocator-aware container. It can only be default created, obtained from std::regex_iterator, or modified by std::regex_search or std::regex_match. Because std::match_results holds std::sub_matches, each of which is a pair of iterators into the original character sequence that was matched, it's undefined behavior to examine std::match_results if the original character sequence was destroyed or iterators to it were invalidated for other reasons.

The first sub_match (index 0) contained in a match_result always represents the full match within a target sequence made by a regex, and subsequent sub_matches represent sub-expression matches corresponding in sequence to the left parenthesis delimiting the sub-expression in the regex.


[edit] Type requirements

BidirIt must meet the requirements of BidirectionalIterator.
Alloc must meet the requirements of Allocator.

[edit] Specializations

Several specializations for common character sequence types are provided:

Defined in header <regex>
Type Definition
cmatch match_results<const char*>
wcmatch match_results<const wchar_t*>
smatch match_results<std::string::const_iterator>
wsmatch match_results<std::wstring::const_iterator>

[edit] Member types

Member type Definition
allocator_type Allocator
value_type std::sub_match<BidirIt>
const_reference const value_type&
reference value_type&
const_iterator implementation defined (depends on the underlying container)
iterator const_iterator
difference_type std::iterator_traits<BidirIt>::difference_type
size_type std::allocator_traits<Alloc>::size_type
char_type std::iterator_traits<BidirIt>::value_type
string_type std::basic_string<char_type>

[edit] Member functions

constructs the object
(public member function)
destructs the object
(public member function)
assigns the contents
(public member function)
returns the associated allocator
(public member function)
checks if the results are available
(public member function)
checks whether the match was successful
(public member function)
returns the number of matches in a fully-established result state
(public member function)
returns the maximum possible number of sub-matches
(public member function)
Element access
returns the length of the particular sub-match
(public member function)
returns the position of the first character of the particular sub-match
(public member function)
returns the sequence of characters for the particular sub-match
(public member function)
returns specified sub-match
(public member function)
returns sub-sequence between the beginning of the target sequence and the beginning of the full match.
(public member function)
returns sub-sequence between the end of the full match and the end of the target sequence
(public member function)
returns iterator to the beginning of the list of sub-matches
(public member function)
returns iterator to the end of the list of sub-matches
(public member function)
formats match results for output
(public member function)
swaps the contents
(public member function)

[edit] Non-member functions

lexicographically compares the values in the two match result
(function template)
specializes the std::swap() algorithm
(function template)