How do you set a radiobutton as selected using code in gtk?

A radiobuttongroup was created and several radiomenuelems were created in that group. Clicking them results in the expected effect, but how do you set a radiobutton using code?

I've searched google fo开发者_Go百科r the answer but I can only find other people asking the same question without an answer such as here: http://markmail.org/message/3cpuikfcyszyf3xy

You can use Gtk::CheckMenuItem::set_active assuming you are asking about gtkmm, or gtk_check_menu_item_set_active from plain old GTK.