28 Regular expressions library [re]

28.10 Class template match_results [re.results]

28.10.3 match_results size [re.results.size]

size_type size() const;

Returns: One plus the number of marked sub-expressions in the regular expression that was matched if *this represents the result of a successful match. Otherwise returns 0. [ Note: The state of a match_results object can be modified only by passing that object to regex_match or regex_search. Sections [re.alg.match] and [re.alg.search] specify the effects of those algorithms on their match_results arguments.  — end note ]

size_type max_size() const;

Returns: The maximum number of sub_match elements that can be stored in *this.

bool empty() const;

Returns: size() == 0.