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tcl::chan::fifo2 - Reflected/virtual channel support
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tcl::chan::fifo2(n) 1 tcllib "Reflected/virtual channel support"


tcl::chan::fifo2 - In-memory interconnected fifo channels


  • package require Tcl 8.5
  • package require TclOO
  • package require tcl::chan::events ?1?
  • package require tcl::chan::halfpipe ?1?
  • package require tcl::chan::fifo2 ?1?


The tcl::chan::fifo2 package provides a command creating pairs of channels which live purely in memory and are connected to each other in a fifo manner. What is written to one half of the pair can be read from the other half, in the same order. One particular application for this is communication between threads, with one half of the pair moved to the thread to talk to. This is equivalent to the fifo2 channels provided by the package Memchan, except that this is written in pure Tcl, not C. On the other hand, Memchan is usable with Tcl 8.4 and before, whereas this package requires Tcl 8.5 or higher, and TclOO.

The internal TclOO class implementing the channel handler is a sub-class of the tcl::chan::events framework.



This command creates a new connected pair of fifo channels and returns their handles, as a list containing two elements.

Bugs, Ideas, Feedback

This document, and the package it describes, will undoubtedly contain bugs and other problems. Please report such in the category virtchannel of the Tcllib Trackers. Please also report any ideas for enhancements you may have for either package and/or documentation.

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