MAKR, 2007-08-01: rechan is a small Tcl extension written in C. It consists of only one C source file and strives to make reflected channels available to the Tcl 8.4 script level. Some basic information extracted from the source file:

  * Written by [Matt Newman] and [Jean-Claude Wippler], as part of [Tclkit].
  * March 2003 - placed in the public domain by the authors.
  * Reflecting [channel] interface

As for how to use it, have a look at Rchan allows channels to be implemented in Tcl.

LV Where does one find this extension?

Rechan is now part of Critlib and can be downloaded from [L1 ]

DKF: See also chan create, which allows for similar capabilities directly in Tcl itself from 8.5 onwards.