NAME

       tcl::chan::halfpipe - In-memory channel, half of a fifo2

SYNOPSIS

       package require Tcl  8.5

       package require TclOO

       package require tcl::chan::events  ?1?

       package require tcl::chan::halfpipe  ?1.0.1?

       ::tcl::chan::halfpipe ?-option value...?

       objectCmd put bytes

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DESCRIPTION

       The  tcl::chan::halfpipe package provides a command creating one half of a tcl::chan::fifo2 pair. Writing
       into such a channel invokes a set of callbacks which then handle the data. This is similar to  a  channel
       handler, except having a much simpler API.

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

API

       ::tcl::chan::halfpipe ?-option value...?
              This command creates a halfpipe channel and configures it with  the  callbacks  to  run  when  the
              channel  is  closed, data was written to it, or ran empty. See the section Options for the list of
              options and associated semantics.  The result of the command is a list  containing  two  elements,
              the  handle of the new channel, and the object command of the channel handler, in this order.  The
              latter is supplied to the caller to provide her with access to the put method for adding  data  to
              the channel.

              Two halfpipes with a bit of glue logic in the callbacks make for one tcl::chan::fifo2.

       objectCmd put bytes
              This  method  of the channel handler object puts the data bytes into the channel so that it can be
              read from it.

OPTIONS

       -close-command cmdprefix
              This callback is invoked when the channel is closed.  A single argument is supplied, the handle of
              the channel being closed.  The result of the callback is ignored.

       -write-command cmdprefix
              This callback is invoked when data is written to the channel.  Two  arguments  are  supplied,  the
              handle of the channel written to, and the data written.  The result of the callback is ignored.

       -empty-command cmdprefix
              This  callback  is  invoked  when  the  channel has run out of data to read.  A single argument is
              supplied, the handle of the channel.

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 [http://core.tcl.tk/tcllib/reportlist].
       Please also report any ideas for enhancements you may have for either package and/or documentation.

       When proposing code changes, please provide unified diffs, i.e the output of diff -u.

       Note further that attachments are strongly preferred over inlined patches. Attachments  can  be  made  by
       going  to the Edit form of the ticket immediately after its creation, and then using the left-most button
       in the secondary navigation bar.

KEYWORDS

       callbacks, fifo, in-memory channel, reflected channel, tip 219, virtual channel

CATEGORY

       Channels

COPYRIGHT

       Copyright (c) 2009, 2019 Andreas Kupries <andreas_kupries@users.sourceforge.net>

tcllib                                                1.0.1                            tcl::chan::halfpipe(3tcl)