32 Regular expressions library [re]

32.10 Regular expression algorithms [re.alg]

32.10.3 regex_search [re.alg.search]

template<class BidirectionalIterator, class Allocator, class charT, class traits>
  bool regex_search(BidirectionalIterator first, BidirectionalIterator last,
                    match_results<BidirectionalIterator, Allocator>& m,
                    const basic_regex<charT, traits>& e,
                    regex_constants::match_flag_type flags = regex_constants::match_default);

Preconditions: BidirectionalIterator models bidirectional_iterator ([iterator.concept.bidir]).

Effects: Determines whether there is some sub-sequence within [first, last) that matches the regular expression e.

The parameter flags is used to control how the expression is matched against the character sequence.

Returns true if such a sequence exists, false otherwise.

Postconditions: m.ready() == true in all cases.

If the function returns false, then the effect on parameter m is unspecified except that m.size() returns 0 and m.empty() returns true.

Otherwise the effects on parameter m are given in Table 143 .

Table 143: Effects of regex_search algorithm [tab:re.alg.search]

🔗	Element	Value
🔗	m.size()	1 + e.mark_count()
🔗	m.empty()	false
🔗	m.prefix().first	first
🔗	m.prefix().second	m[0].first
🔗	m.prefix().matched	m.prefix().first != m.prefix().second
🔗	m.suffix().first	m[0].second
🔗	m.suffix().second	last
🔗	m.suffix().matched	m.suffix().first != m.suffix().second
🔗	m[0].first	The start of the sequence of characters that matched the regular expression
🔗	m[0].second	The end of the sequence of characters that matched the regular expression
🔗	m[0].matched	true
🔗	m[n].first	For all integers 0 < n < m.size(), the start of the sequence that matched sub-expression n. Alternatively, if sub-expression n did not participate in the match, then last.
🔗	m[n].second	For all integers 0 < n < m.size(), the end of the sequence that matched sub-expression n. Alternatively, if sub-expression n did not participate in the match, then last.
🔗	m[n].matched	For all integers 0 < n < m.size(), true if sub-expression n participated in the match, false otherwise.

🔗

template<class charT, class Allocator, class traits>
  bool regex_search(const charT* str, match_results<const charT*, Allocator>& m,
                    const basic_regex<charT, traits>& e,
                    regex_constants::match_flag_type flags = regex_constants::match_default);

Returns: regex_search(str, str + char_traits<charT>::length(str), m, e, flags).

🔗

template<class ST, class SA, class Allocator, class charT, class traits>
  bool regex_search(const basic_string<charT, ST, SA>& s,
                    match_results<typename basic_string<charT, ST, SA>::const_iterator,
                                  Allocator>& m,
                    const basic_regex<charT, traits>& e,
                    regex_constants::match_flag_type flags = regex_constants::match_default);

Returns: regex_search(s.begin(), s.end(), m, e, flags).

🔗

template<class BidirectionalIterator, class charT, class traits>
  bool regex_search(BidirectionalIterator first, BidirectionalIterator last,
                    const basic_regex<charT, traits>& e,
                    regex_constants::match_flag_type flags = regex_constants::match_default);

Effects: Behaves “as if” by constructing an object what of type match_results<BidirectionalIterator> and returning regex_search(first, last, what, e, flags).

🔗

template<class charT, class traits>
  bool regex_search(const charT* str,
                    const basic_regex<charT, traits>& e,
                    regex_constants::match_flag_type flags = regex_constants::match_default);

Returns: regex_search(str, str + char_traits<charT>::length(str), e, flags).

🔗

template<class ST, class SA, class charT, class traits>
  bool regex_search(const basic_string<charT, ST, SA>& s,
                    const basic_regex<charT, traits>& e,
                    regex_constants::match_flag_type flags = regex_constants::match_default);

Returns: regex_search(s.begin(), s.end(), e, flags).