[sigc] ANNOUNCE: libsigc++ 1.9.12 (aka libsigc++ 2.0 beta 1)

[Martin Schulze <martin-ml hippogriff de>]

*** libsigc++ 2.0 (beta)

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.

libsigc++ is used by gtkmm to wrap the GTK+ signal system. It does not
depend on GTK or gtkmm.

libsigc++ 2.0 uses modern C++ mechanisms to achieve a highly flexible,
yet typesafe callback system. It supports all features of libsigc++ 1.2
and improves upon it with a simpler and more powerful API. The old API
is preserved by means of a deprecated compatibility module.

In particular the API improvements from libsigc++ 1.2 to 2.0 include:
* Provides unnumbered signal and slot templates.
* Supports arbitrary functor types.
* Supports implicit argument type conversions on signal emission.
* Adds support for overloaded functions.
* Borrows powerful accumulator interface from boost::signal.
* Simplifies use of adaptors: argument types need not be specified any
  more (except for sigc::retype_return()).
* More powerful adaptors: position of arguments to hide or bind can
  be chosen freely.
* Adds two useful adaptors: sigc::compose(), sigc::exception_catch().
* Adds all-in-one operator sigc::group() with support for lambdas
  featuring a complete set of lambda selectors and lambda operators.
* Highly optimizable: performs only one indirect function call during
  slot invokation independant of the number of adaptors used.
* Conforms to the STL naming scheme: only uses small letters.


*** Prerequisits

Compatible compilers must supports the following recent c++ techniques:
* Partial template (function) specialization.
* Arithmetics in template arguments.
* Explicit template (member) function instantiation.
* Treat void return as normal return.


*** Changes:

1.9.12:

This is the first beta release of libsigc++ 2.0. No more API additions
should be made. Future work concentrates on supporting more compilers,
bug hunting and finishing the documentation. Changes in this release:
* Added adaptor retype(). With this final API addition all adaptors
  are in place that are available in libsigc++-1.2.
* Added negation lambda operator. Use STL names for lambda actions.
* Remove formerly disabled support for gcc extension typeof().
* Added project files for MS Visual Studio .Net 2003. (Roel Vanhout)
* Make libsigc++2 compile with .Net 2003. (Roel Vanhout,Martin Schulze)
* Build shared version of libsigc++2 by default. (Cedric Gustin)
* Add support for win32 platform. (Cedric Gustin)
* Install .m4 files. (requested by Ron Steinke)
* Cleaned up functors .m4 files for ptr_fun() and mem_fun().
* Restructured and completed documentation of the core library parts.


*** Download:

libsigc++ is available for download here:
http://libsigc.sourceforge.net/

A reference documentation for libsigc++ 2.0 can be found here:
http://libsigc.sourceforge.net/libsigc2/docs/


*** Known issues:

* This release has only been tested with gcc-3.2. It should also
  compile with:
  - gcc-3.3, gcc-3.3.x
  - cygwin (gcc >= 3.2)
  - mingw32
  - Microsoft Visual Studio .Net 2003
  - Sun Forte C++ compiler
  Please report any troubles you encounter with these compilers!
  You are also invited to try a different compiler.

* When the compatibility module is used with "using namespace SigC",
  gcc-3.2 reports conflicts of SigC::slot() with struct sigc::slot.
  A hackish work-around has been disabled to support the .Net compiler.

* Adaptors are not documented, yet.