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>