Re: [dev] Culling all the way down

From: Mattias Andrée <>
Date: Mon, 7 Sep 2020 18:52:47 +0200

On Mon, 7 Sep 2020 10:13:26 +0300
Alexander Krotov <> wrote:

> > What you could do is to patch a terminal to allow programs to because
> > paused via SIGSTOP when invisible and continued via SIGCONT when
> > visible. Then your program would only need to write some string to
> > the terminal when it starts and when it terminates. Multiplexers
> > could however become an issue, but you could patch one as well.
> Sending SIGSTOP stops even the programs that simply do something in the
> background, like software update. This will make it impossible to run
> something like "apt-get upgrade" in invisible terminal.

I meant that this would be something the application would explicitly
have to opt in for by writing a special string to the terminal.

> Maybe a better solution is to send XOFF (see
>, but I am also not
> sure how other programs react to it. They will probably block waiting
> for the write(2) syscall to return instead of continuing to do work in
> the background.
> If they use separate threads/coroutines for the work and for progress
> bar update, they will continue to work while progress bar will be
> blocked. Once unlocked, they will send the rest of previous progress bar
> update, skip all the "frames" that were never displayed and display the
> final state.
> Looks like doing an XOFF patch for st and fixing all the programs that
> can't handle it properly is the "right thing", but prepare to discover
> that badly written programs will stop or even timeout with an error.
Received on Mon Sep 07 2020 - 18:52:47 CEST

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