devel/libsigc++3 3.6.0 NetBSD

libsigc++ implements a full callback system for use in widget libraries, abstract interfaces, and general programming. Originally part of the Gtk-- widget set, libsigc++ is now a separate library to provide for more general use. It is the most complete library of its kind with the ability to connect an abstract callback to a class method, function, or function object. It contains adaptor classes for connection of dissimilar callbacks and has an ease of use unmatched by other C++ callback libraries.

This is major version 3 of the library.