The tutorial explains that signal parameters can be specified as extra template argument, e.g. sigc::signal<void, std::string>. However, when I try this I get a compile error:

error: implicit instantiation of undefined template 'sigc::signal<void, std::__1::basic_string<char> >'

Looking at the code in this repo's examples/ folder, it seems like nowadays I should write sigc::signal<void(std::string)> instead. It would be great if the tutorial could be updated accordingly so that others don't have to go through the same confusion. Thanks!