TCL IPv6 enabled	( nGn systems for Euro6IX -2003 ):
=======================================================

Send comments, questions to : rafael.martinez@novagnet.com



0.- Abstract
1.- ChangeLog
2.- Detected bugs
3.- TODO
4.- Installing
5.- Usefull notes for programmers.




0.- Abstract
-------------
	TCL is  powerfull scripting language, runnable at different
	platforms (Unix, win, macos) allowing some O.S facilites,
	file-access, socket programming. It's widely known by one of
	its graphical libraries, Tk.

	This patch enables the TCL interpreter to connect and bind
	with IPv6 addresses, provided your O.S platform is IPv6
	enabled.

	If the old API socket allowed:

	% socket www.elmundo.es 80
	% socket 157.97.34.524 23
	% socket 157.97.34.524 echo
	% socket -server accept 9999

	now, you can also type:

	% socket linux-g.ngn.euro6ix.org 7
	% socket linux-g.ngn.euro6ix.org echo
	% fconfigure sock3
	% socket 2003:800:40:2a05::10 23
	% socket -server accept 9999 
  

1.- ChangleLog
----------------

+ 2004-05-10: Fixing a misstype error.
		"TCP_IPv6" instead of "TCL_IPv6"
		(socket -myaddr 2001:800::fe12:4023::1 irck.ert.com 7777 ) was failure
		Now it is fixed
+ 2003-10-04: Unix version available. Tested on:
		    i386-unknown-linux
		    i386-freebsd-5.1
		    i386-solaris-sun

2.- Detected bugs
-----------------

3.- TODO
---------

	+ Trying the port to non-Unix systems ( win32 ,macos...)
	+ A more exhaustive test for IPv6 capabilities by rewriting socket.test


4.- Installing 
--------------
	- Download tcl8.4.4-src.tar.gz from 

	http://tcl.sourceforge.net/

	- Download tcl-8.4.4-v6-20031005.diff from

	http://www.ngn.euro6ix.org/IPv6/tcl


	bash-2.04$ tar xzvf /path/to/tcl8.4.4-src.tar.gz	
	bash-2.04$ patch -p0 < /path/to/tcl-8.4.4-v6-20031005.diff
	bash-2.04$ cd tcl8-4.4/unix
	bash-2.04$ autoconf **
	bash-2.04$ ./configure --prefix=$HOME --enable-ipv6
	bash-2.04$ make
	bash-2.04$ make test ***
	bash-2.04$ make install



	** This pass is necessary for building the next configurew
           script.
	   A crash has been detected by using newer versions of
           autoconf (2.57) . This is NOT properly a bug from the IPv6
           patch (it also occurs without applying it) , but a
           backwards syntax-compatibility with the old
           format on m4 files. When trouble , you can
		  - Either Install locally GNU autoconf <=2.52
		  - Or get the "configure" script on a operative boss
           and copy here, without loss of portability. (also present
           at the above URL's )

	*** 'make test' may fail depending if you are running a
            "private" IP and there are problems with DNS
            resolution. This used to happen even at non-patched
            version. Read the "socket.test" info . If you
            run the test with a public IP, you will be
            succesfull. Running IPv6-patched 'make test' under the
            same circunstances should be  right. Even if 'make test'
            fails at socket.test module, you are warrantied to use it
            at your TCL programs.


5.- Usefull notes for programmers.
---------------------------------


	Advanced control on sockets: 
	-----------------------------
	Remember that original tcl-8.4.4 did not deal with UDP
	sockets. Neither this patch 

	DNS resolution:
	------------
	DNS resolution solves firstly IPv6 address, if this exists, IPv4
	otherwise. This may make your programs surprisingly fail if
	the remote server exports the service on IPv4, but not on
	IPv6.