30 Regular expressions library [re]

30.9 Class template match_­results [re.results]

30.9.9 Non-member functions [re.results.nonmember]

template<class BidirectionalIterator, class Allocator> bool operator==(const match_results<BidirectionalIterator, Allocator>& m1, const match_results<BidirectionalIterator, Allocator>& m2);
Returns: true if neither match result is ready, false if one match result is ready and the other is not.
If both match results are ready, returns true only if:
  • m1.empty() && m2.empty(), or
  • !m1.empty() && !m2.empty(), and the following conditions are satisfied:
    • m1.prefix() == m2.prefix(),
    • m1.size() == m2.size() && equal(m1.begin(), m1.end(), m2.begin()), and
    • m1.suffix() == m2.suffix().
[Note 1:
The algorithm equal is defined in [algorithms].
— end note]