Version 3 of Cygwin

Purpose: discuss this Microsoft Windows development environment's pros and cons

What is Cygwin?
Where can I learn more?
Does it come with Tcl? With Tk?
Why is there such problems using TEA under Cygwin?
What compiler shoul I use with cygwin?
Are there any special add-on packages that would be useful when developing with Cygwin?
What is Cywin?

      Cygwin is a program package that tries to provide a Unix-like 
      environments on a Win32 System (that is Win95,98, NT, Win2000,
      maybe also WinXP?). Thus there are a lot of standard Unx-programs
      ported to Win32 (bash, gcc, ... AND Tcl/TK). And it is FREE.

Where can I learn more?

      http://www.cygwin.com

Does it come with Tcl? With Tk?

      Yes. But note that it comes along with its own version of wish 
      and Tcl/Tk which differs from the official version of
      Win32-version of www.scriptics.com. Probably it is not as much
      up to date as the official version. On the other hand you have the
      opportunety to extend wish or tclsh with your own functionality
      by linking the cygwin-tcl/tk-libraries with your C-funtions (for
      example by using swig [www.swig.org]).

What compiler should I use with cygwin?

      cygwin-gcc (part of the cygwin package)