Tcl/Tk 8.6b2 Release Announcement
August 5, 2011

The Tcl Core Team is pleased to announce the 8.6b2 releases of the Tcl
dynamic language and the Tk toolkit.  This is the second beta release
of Tcl/Tk 8.6.  More details can be found below.  We would like to
express our gratitude to all those who submit bug reports and patches.
This information is invaluable in enabling us to identify and eliminate
problems in the core.

Where to get the new releases:
------------------------------

Tcl/Tk 8.6b2 sources are freely available as open source from the
Tcl Developer Xchange web site at:

        http://www.tcl.tk/software/tcltk/8.6.html

This web page also contains additional information about the releases,
including new features and notes about installing and compiling the
releases.  Sources are always available from the Tcl SourceForge
project's file distribution area:

        http://sourceforge.net/projects/tcl/files/

Binaries for most major platforms are available from:

        http://www.activestate.com/Tcl

For additional information:
---------------------------

Please visit the Tcl Developer Xchange web site:

        http://www.tcl.tk/

This site contains a variety of information about Tcl/Tk in general, the
core Tcl and Tk distributions, Tcl development tools, and much more.

Summary of Changes since Tcl/Tk 8.6b1:
--------------------------------------

The following were the main changes in Tcl/Tk 8.6b2.  A complete list
can be found in the changes file at the root of the source tree.  The
more complete ChangeLog is also included with each source release.

This is a beta release of 8.6.  The beta designation means that the
feature set for 8.6 is believed to be complete, and the focus is now
on testing and bug fixing moving quickly toward an 8.6.0 release.
All relevant bug fixes (and some more) up to and including 8.5.10 changes
are included in 8.6b2.  This release is a development release, and should
only be considered for deployment use after considerable testing.

   * [TIP 364]	Default build configuration is now --enable-threads.
		Bundled distribution of package Thread 2.6.7.
        *** POTENTIAL INCOMPATIBILITY ***

   * [TIP 244] PNG format support in photo images.

   * [TIP 162] IPv6 networking support.

   * Mac OS X: Tk now built on Cocoa.
        *** POTENTIAL INCOMPATIBILITY ***
	*** Use --enable-aqua=carbon configure option to force use of ***
	*** unsupported legacy Carbon sources.  Required for pre-Leopard ***

   * [TIP 354] New OO: [info object namespace], Tcl_GetObjectName().

   * [TIP 381] New OO commands: [info ... call] [self call] [nextto].

   * [TIP 50] Bundled distribution of package Itcl 4.0b7.

   * Tcl_Exit()/[exit] no longer calls for a full Tcl_Finalize().
	*** POTENTIAL INCOMPATIBILITY for exit handlers ***

   * Enhanced command: [$treeview tag names|add|remove].

   * [$image write -file] uses file name extension to select image format.

   * New format support: [$photo data -format GIF]

   * Enhanced command: [$notebook config -tabposition]

   * [TIP 171] Revised default handling of <MouseWheel> events.
	*** POTENTIAL INCOMPATIBILITY ***

   * [TIP 348] Enhanced commands: [info errorstack], [return -errorstack]

   * [TIPs 353,356] New interfaces for NRE support by extensions.

   * [TIP 357] New routines Tcl_LoadFile(), Tcl_FindSymbol(), etc.

   * [TIP 234] Revised Tcl_Zlib*() interfaces.
	*** INCOMPATIBILITY with interface of 8.6b1 ***

   * Converted to ensembles: [array], [file], [namespace], [$w identify]

   * Bytecode compiled: [error], [subst], [throw], [try], [unset]

   * NRE support in coroutines and in [namespace unknown], [for], [if]
     [source], [subst], [switch] and [while].

   * Updated packages:
	- registry 1.3
		-32bit | -64bit switches [TIP 362]
	- http 2.8.2
		Support for chunked+gzip modes.
	- tcltest 2.3.3
	- tdbc 1.0b17
	- msgcat 1.4.4
	- platform 1.0.10
	- TclOO 0.6.3
	- tile 0.8.6

   * Improved ckalloc(), ckfree() macros require less casting by callers.

   * tclsh/wish support for Unicode command line arguments on Windows.

   * When a channel gets std channel status on creation, it now gets a
     the appropriate name matching std*, and no other.
	*** POTENTIAL INCOMPATIBILITY for reliance on channel names ***

   * Tcl_ObjType "option" no longer registered.
	*** POTENTIAL INCOMPATIBILITY for Tcl_GetObjType("option") ***

   * Greatly expanded use of -errorcode by builtin commands.

--
Tcl Core Team and Maintainers
Don Porter, Tcl Core Release Manager