'''`[http://www.tcl.tk/man/tcl/TclCmd/chan.htm%|%chan] configure`''', a
[Tcl Commands%|%built-in] [Tcl] command, sets and retrieves options for
[channel]s.  It replaces the older `[fconfigure]`.


** Synopsis **

    :   '''chan configure''' ''channelId''
    :   '''chan configure''' ''channelId name''
    :   '''chan configure''' ''channelId name value'' ?''name value ...''?


** Documentation **

   [http://www.tcl.tk/man/tcl/TclCmd/chan.htm%|%official reference]:   



** See Also **

   [channel]:   
   
   [open]:   
   
   [socket]:   


** Examples **

Instruct Tcl to always send output to stdout immediately, whether or not it is to a terminal:

======
chan configure stdout -buffering none
======

Instruct Tcl to read pure bytes from a channel and write bytes to it, rather
than characters:

======
chan configure $binaryDataFile -translation binary
======



** Encoding **

The real name of the `binary` encoding is `iso8859-1`.  `-encoding binary` was
introduced as a migration aid to help with either the 7.6 -> 8.0 or the 8.0 to
8.1 transitions.

`iso8859-1` has the privileged relationship with [Unicode] that its code-points are
in a one-to-one relationship with `\u0000`-`\u007f`

Caveat:  `-encoding binary` turns off `-translation`, but `-encoding iso8859-1`
does not.

    :   ref [dgp] and [kbk] in [Tcl Chatroom] ,2013-12-02

** stdout encoding bug **

[RS] 2015-04-13 - On Windows 7, stdout (if not redirected) breaks in a funny way when the encoding is changed - notice the "%" prompt:

 D:\>Tcl85\bin\tclsh
 % fconfigure stdout -encoding utf-8
 ‥
 ‥^C
 D:\>Tcl86\bin\tclsh
 % fconfigure stdout -encoding utf-8
 ‥exit

With longer output, the whole console (Cygwin bash in cmd.exe) freezes and can only be closed, but no longer be used. In cmd.exe without Cygwin, Ctrl-C makes the console responsive again.

A workaround in both cases is to pipe stdout through [cat]. When stdout is redirected to a file, the problem is likewise not seen.

This behavior was not the case in Tcl 8.4:

 D:\>Tcl84\bin\tclsh
 % fconfigure stdout -encoding utf-8
 %

** Misc **

[LV] 2008 Feb 28:

Some of the wiki pages talk about the construct,

===
chan configure $serial_port -mode "$baudRate,$plex,$bits,$polarity"
===

or some such thing. The -mode flag, used for specifying baud rate, etc,  has
moved to [open] now. I don't know how one would change those values on an open
descriptor...

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