Question

Say I’ve registered a callback by the following command:

fileevent stdin readable someCallback

Now I want to unregister the someCallback so that it will not be called when for the standard input.

How can I do that?

Answer 1

See the documentation, just call it with an empty string as script.

fileevent stdin readable "" ;# delete readable handler for stdin

If the script argument is specified as an empty string then the event handler is deleted, so that no script will be invoked. A file event handler is also deleted automatically whenever its channel is closed or its interpreter is deleted.

http://www.tcl.tk/man/tcl8.6/TclCmd/fileevent.htm