Inheriting and overriding functions of a std::string?

Question

Since std::string is actually a typedef of a templated class, how can I override it? I want to make a UTF-8 std::string that will return the correct length, among other things.

Answer 1

If you must define your own string type, then don't inherit from std::string but define your own Character Traits class and do something like

typedef std::basic_string<unsigned char, utf8_traits> utf8string;

See also Herb Sutter's website.

Answer 2

DON'T DERIVE FROM STRING

std::string, that is, basically the whole basic_string template is not designed to be derived from. There are zillions of articles about that already. It doesn't have any virtual functions so there is nothing to override. The best you can do is hide something. Best is to use composition/aggregation! That is, just keep a member of type string in your class and forward the calls! Again, just to make sure

DON'T DERIVE FROM STRING

Answer 3

It is generally considered a mistake in C++ to derive from a standard library container. However, the functionality you are looking for has already been implemented. Have a look at Glib::ustring.

Hope this helps!