libsigc++

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. Features:

• Compile time typesafe callbacks (faster than run time checks)
• Typesafety violations report line number correctly with template names (no tracing template failures into headers)
• No compiler extensions or meta compilers required
• Proper handling of dynamic objects and signals (deleted objects will not cause seg faults)
• Extendable API at any level: signal, slot, connection and trackable
• Extensions do not require alteration of basic components
• User definable accumulators
• A variety of adaptors to change the callback signature: bind, hide, retype, compose and lambda call groups
• Various compilers and platforms are supported: gcc, cygwin, mingw32, MS .NET 2003, Sun Forte C++, Compaq C++, Intel C++