OK, so the situation is that you're writing to a Tcl_Channel
that a Tcl interpreter is also writing to. That should work. The simplest way to put paging on top of that is to make that channel be one of the standard channels (I'd pick stdout
) and feed the whole lot through a pager program like more
or less
. That'll only take you a few seconds to get working.
Otherwise, it's possible to write a channel in Tcl 8.5 using just Tcl code; that's what a reflected channel is (that's the Tcl 8.6 documentation, but it works the same way in 8.5). However, using that to do a pager is going to be quite a lot of work; channels work with bytes not characters. It's probably also possible to do it using a stacked channel transformation (8.6 only).
However, if sending the output to a Tk text widget is acceptable (I know it isn't precisely what you asked for…) there's already a package in Tcllib for it.
package require Tk
package require tcl::chan::textwindow
pack [text .t]
set channel [tcl::chan::textwindow .t]
puts $channel "This is a simple test."
That (write-only) channel will work fine if you pass it to your C++ code to use. (You can inspect the source to see how it is done if you wish; the code is pretty short.)