The regular expression matching function tt(std::regex_match)hi(regex_match)
returns tt(true) if the regular expression defined in its provided
tt(regex) argument em(fully) matches the provided target text. This means that
tt(match_results::prefix) and tt(match_results::suffix) must return empty
strings. But defining sub-expressions is OK.

The following overloaded variants of this function are available:
    itemization(
    ittq(bool regex_match(BidirConstIter first, BidirConstIter last,
                  std::match_results &results,
                  std::regex const &re))
       (tt(BidirConstIter) is a bidirectional const iterator. The range
        rangett(first, last) defines the target text. The match results are
        returned in tt(results). The types of the iterators must match the
        type of the tt(match_results) that's used. E.g., a tt(cmatch) should
        be used if the iterators are of tt(char const *) types, and a
        tt(smatch) should be used if the iterators are of
        tt(string::const_iterator) types. Similar correspondence requirements
        hold true for the other overloaded versions of this function;)

    ittq(bool regex_match(BidirConstIter first, BidirConstIter last,
        std::regex const &re))
       (this function behaves like the previous function, but does not
        return the results of the matching process in a tt(match_results)
        object;)

    ittq(bool regex_match(char const *target,
                  std::match_results &results, std::regex const &re))
       (this function behaves like the first overloaded variant, using
        the characters in tt(target) as its target text;)
        
    ittq(bool regex_match(char const *str, std::regex const &re))
       (this function behaves like the previous function but does not return
        the match results;)

    ittq(bool regex_match(std::string const &target,
                  std::match_results &results, std::regex const &re))
       (this function behaves like the first overloaded variant, using
        the characters in tt(target) as its target text;)

    ittq(bool regex_match(std::string const &str, std::regex const &re))
       (this function behaves like the previous function but does not return
        the match results;)

    itt(bool regex_match(std::string const &&, std::match_results &, 
                         std::regex &) = delete)
       (the tt(regex_match) function does not accept temporary tt(string)
        objects as target strings, as this would result in invalid string
        iterators in the tt(match_result) argument.)
    )
    Here is a small example: the regular expression matches the matched text
(provided by tt(argv[1])) if it starts with 5 digits and then 
merely contains  letters (tt([[:alpha:]])). The digits can be retrieved as
sub-expression 1:
        verb(    #include <iostream>
    #include <regex>
    
    using namespace std;
    
    int main(int argc, char const **argv)
    {
        regex re("(\\d{5})[[:alpha:]]+"); 

        cmatch results;

        if (not regex_match(argv[1], results, re))
            cout << "No match\n";
        else
            cout << "size: " << results.size() << ": " << 
                    results.str(1) << " -- " << results.str() << '\n';
    })

