RegexMatch template

Question

I'm trying to convert this function to a template.

std::vector<std::smatch> RegexMatchAll(const std::string& str, std::string regex)  
{  
    std::vector<std::smatch> result;  
  
    std::regex re(regex);  
    auto words_begin = std::sregex_iterator(str.begin(), str.end(), re);  
    auto words_end = std::sregex_iterator();  
  
    for (std::sregex_iterator i = words_begin; i != words_end; ++i) {  
        std::smatch match = *i;  
        result.emplace_back(match);  
    }  
  
    return result;  
}  

So far what I have already done:

template <typename T>  
auto RegexMatchAll(const std::basic_string<T>& str, const std::basic_string<T>& regex)  
{  
    using iter = typename std::basic_string<T>::const_iterator;  
    std::basic_regex<T> re(regex);  
  
    std::vector<std::match_results<iter>> result;  
  
    auto words_begin = iter(str.begin(), str.end(), re);  
    auto words_end = iter();  
  
    for (iter i = words_begin; i != words_end; ++i) {  
        std::match_results<iter> m = *i;  
        result.emplace_back(m);  
    }  
  
    return result;  
}  

I'm getting some errors like:

<function-style-cast>': cannot convert from 'initializer list' to 'iter  
  
'words_begin': cannot be used before it is initialized  

And I'm calling the template as:

auto matches = RegexMatchAll(str, R"(...)"s);  
auto matches = RegexMatchAll(wstr, LR"(...)"s);