| Defined in header <regex> | ||
|---|---|---|
template<
class BidirIt
> class sub_match; | (since C++11) |
The class template 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 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.
sub_match inherits from std::pair<BidirIt, BidirIt>, although it cannot be treated as a std::pair object because member functions such as swap and assignment will not work as expected.
Type requirements
- BidirIt must meet the requirements of BidirectionalIterator. |
Specializations
Several specializations for common character sequence types are provided:
| Defined in header <regex> | |
|---|---|
| Type | Definition |
csub_match | sub_match<const char*> |
wcsub_match | sub_match<const wchar_t*> |
ssub_match | sub_match<std::string::const_iterator> |
wssub_match | 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
| constructs the match object (public member function) | |
Observers | |
| returns the length of the match (if any) (public member function) | |
| converts to the underlying string type (public member function) | |
| compares matched subsequence (if any) (public member function) | |
Non-member functions
compares two sub_match objects (function) | |
| outputs the matched character subsequence (function template) |
See also
| (C++11) | iterates through regex submatches (class template) |
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