libsigc++ implements a typesafe callback system for standard C++. It allows you to define signals and to connect those signals to any callback function, either global or a member function, regardless of whether it is static or virtual.
It also contains adaptor classes for connection of dissimilar callbacks and has an ease of use unmatched by other C++ callback libraries. Libsigc++ is licensed under the GNU Library General Public License, LGPL.
See attached ebuild
P.S.: This ebuild uses SLOT="2", since this version of libsigc++ is meant to coexist with older ones. Headers, pkgconfig files and lib files all use "-2.0" suffix, so I named slot "2", even though version is 1.9.x - I guess they'll change it to 2.0.x once they go stable.
Created attachment 28024 [details]
An ebuild file for libsigc++-1.9.15
I forgot to add the EBUILD keyword, sorry.
this has already been fixed