c++ - std::regex_token_iterator with empty regex -


my understanding std::regex_token_iterator documentation empty iterator equal end iterator:

for (std::regex_token_iterator = ...; != regex_token_iterator{}; ++it) {     ... }

but when create std::regex_token_iterator non-matching regex empty regex seems never reaches end iterator:

auto str = std::string{"any string"}; auto regex = std::regex{""}; auto = std::regex_token_iterator{str.cbegin(), str.cend(), regex, -1}; auto const end = std::regex_token_iterator{}; // following loop goes infinite while (it != end) {     ++it; }

why? missing something?

i'm using xcode's clang (apple llvm 8.1)

edit: seems doesn't matter if non-matching or matching regex (even if last argument zero


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