From: Corinna Vinschen <corinna-cygwin@cygwin.com>
To: Takashi Yano <takashi.yano@nifty.ne.jp>
Cc: cygwin-developers@cygwin.com
Subject: Re: [PATCH v5 1/1] Cygwin: pty: add pseudo console support.
Date: Thu, 08 Aug 2019 19:24:00 -0000 [thread overview]
Message-ID: <20190808192429.GS11632@calimero.vinschen.de> (raw)
In-Reply-To: <20190725143149.GD11632@calimero.vinschen.de>
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Hi Takashi,
desperately trying again, this time directly to you. I hope you're
doing well.
Corinna
On Jul 25 16:31, Corinna Vinschen wrote:
> I hope you're still with us?
>
>
> Corinna
>
> On Jun 24 12:53, Corinna Vinschen wrote:
> > On Apr 16 11:16, Corinna Vinschen wrote:
> > > On Apr 16 09:41, Takashi Yano wrote:
> > > > On Mon, 15 Apr 2019 10:38:32 +0200 Corinna Vinschen wrote:
> > > > > This is supposed to be combined with the preceeding code to a single
> > > > > expression in the end, right?
> > > >
> > > > Do you mean this code and the preceding code should be executed
> > > > exclusively? If so, the answer is no. If the stderr is pty slave,
> > > > the message should be written to both output_handle and
> > > > output_handle_cyg. The reason will be described later.
> > > >
> > > > > I don't quite understand why writing
> > > > > to STD_ERROR_HANDLE doesn't work. Is STD_ERROR_HANDLE not connected
> > > > > to the ConPty?
> > > >
> > > > You are right. STD_ERROR_HANDLE (output_handle) is connected to
> > > > the ConPTY. The data written to output_handle is fowarded to
> > > > to_master_cyg in the master, then displayed. to_master_cyg is
> > > > duplicated to output_handle_cyg in the slave. Therefore, both
> > > > writing to output_handle and writing to output_handle_cyg seem
> > > > to work, at first glance.
> > > >
> > > > However, in the fact, the code below stops forwarding if the
> > > > process is a cygwin process.
> > > > + /* Avoid duplicating slave output which is already sent to
> > > > + to_master_cyg */
> > > > + if (!get_ttyp ()->switch_to_pcon)
> > > > + continue;
> > > >
> > > > The role of the code above is as follows. ConPTY sometimes redraws
> > > > screen based on its own screen buffer. The screen buffer has only
> > > > the data written to output_handle. Basically, cygwin apps use
> > > > output_handle_cyg and native apps use output_handle. Terefore,
> > > > outputs from cygwin apps are disappeared at that time. To avoid
> > > > this, the data write to output_handle_cyg is pushed into the ConPTY
> > > > screen buffer by WriteFile() to output_handle. To prevent the data
> > > > from being displayed twice, forwarding is stopped by the code above
> > > > if the process is a cygwin app.
> > > >
> > > > In strace.cc, writing to output_handle is necessary for pushing
> > > > the data into ConPTY screen buffer, and writing to output_handle_cyg
> > > > is necessary for displaying it.
> > >
> > > Huh, crazy. Thanks for explaining the context.
> > >
> > > >
> > > > > > + fhandler_base *fh = ::cygheap->fdtab[2];
> > > > > > + if (fh && fh->get_major () == DEV_PTYS_MAJOR)
> > > > >
> > > > > For a quick test if the process is connected to a pty, you can
> > > > > use `if (istty_slave_dev (myself->ctty))'
> > > >
> > > > Thanks for advice. My code is checking if the stderr is pty or
> > > > not, and write the message to output_handle_cyg if the stderr
> > > > is pty. If the stderr is redirected to another device, writing
> > > > is not done. Does istty_slave_dev() checking work same for
> > > > stderr if it is redirected? How can I get output_handle_cyg
> > > > after checking using istty_slave_dev()?
> > >
> > > Well... I didn't really think about it. YOu would have to
> > > fetch ::cygheap->fdtab[2] anyway so checking myself->ctty
> > > doesn't really help.
> >
> > Any news on this? Do you consider the latest state from April
> > stable enough for master?
> >
> >
> > Thanks,
> > Corinna
> >
> > --
> > Corinna Vinschen
> > Cygwin Maintainer
>
>
>
> --
> Corinna Vinschen
> Cygwin Maintainer
--
Corinna Vinschen
Cygwin Maintainer
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next prev parent reply other threads:[~2019-08-08 19:24 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-30 13:08 Pseudo console support in PTY Takashi Yano
2019-03-30 19:47 ` Corinna Vinschen
2019-03-30 19:59 ` Corinna Vinschen
2019-03-30 23:07 ` Thomas Wolff
2019-03-31 14:38 ` Corinna Vinschen
2019-03-31 15:00 ` Takashi Yano
2019-04-02 11:02 ` Corinna Vinschen
2019-04-02 17:16 ` Thomas Wolff
2019-04-02 17:51 ` Corinna Vinschen
2019-04-03 7:18 ` Thomas Wolff
2019-04-03 7:28 ` Corinna Vinschen
2019-04-03 7:55 ` Thomas Wolff
2019-04-03 8:02 ` Corinna Vinschen
2019-04-03 11:33 ` Thomas Wolff
2019-04-03 12:17 ` Corinna Vinschen
2019-04-04 4:17 ` Takashi Yano
2019-04-04 8:06 ` Corinna Vinschen
2019-04-04 4:15 ` Takashi Yano
2019-04-03 16:36 ` [PATCH v2 0/1] Pseudo console support in PTY (v2) Takashi Yano
2019-04-03 16:37 ` [PATCH v2 1/1] Cygwin: pty: add pseudo console support Takashi Yano
2019-04-03 16:50 ` [PATCH v2 0/1] Pseudo console support in PTY (v2) Corinna Vinschen
2019-04-04 5:27 ` Takashi Yano
2019-04-04 8:17 ` Thomas Wolff
2019-04-04 9:34 ` Takashi Yano
2019-04-03 17:11 ` Corinna Vinschen
2019-04-04 8:59 ` Takashi Yano
2019-04-04 10:46 ` Corinna Vinschen
2019-04-06 11:13 ` [PATCH v3 0/1] Pseudo console support in PTY (v3) Takashi Yano
2019-04-06 11:14 ` [PATCH v3 1/1] Cygwin: pty: add pseudo console support Takashi Yano
2019-04-06 17:43 ` [PATCH v3 0/1] Pseudo console support in PTY (v3) Corinna Vinschen
2019-04-12 10:22 ` [PATCH v4 0/1] Pseudo console support in PTY (v4) Takashi Yano
2019-04-12 10:23 ` [PATCH v4 1/1] Cygwin: pty: add pseudo console support Takashi Yano
2019-04-12 12:29 ` [PATCH v4 0/1] Pseudo console support in PTY (v4) Corinna Vinschen
2019-04-15 8:18 ` Corinna Vinschen
2019-04-15 23:17 ` Takashi Yano
2019-04-14 15:23 ` [PATCH v5 0/1] Pseudo console support in PTY (v5) Takashi Yano
2019-04-14 15:23 ` [PATCH v5 1/1] Cygwin: pty: add pseudo console support Takashi Yano
2019-04-15 8:38 ` Corinna Vinschen
2019-04-16 0:41 ` Takashi Yano
2019-04-16 9:16 ` Corinna Vinschen
2019-06-24 10:53 ` Corinna Vinschen
2019-07-25 14:31 ` Corinna Vinschen
2019-08-08 19:24 ` Corinna Vinschen [this message]
2019-08-12 12:07 ` Takashi Yano
2019-08-12 12:50 ` Corinna Vinschen
2019-08-12 14:36 ` Takashi Yano
2019-04-14 16:06 ` [PATCH v5 0/1] Pseudo console support in PTY (v5) Takashi Yano
2019-04-16 1:49 ` Takashi Yano
2019-04-16 1:51 ` Takashi Yano
2019-04-06 21:33 ` [PATCH v3 0/1] Pseudo console support in PTY (v3) Thomas Wolff
2019-04-07 5:05 ` Takashi Yano
2019-04-07 12:02 ` Takashi Yano
2019-04-07 21:21 ` Thomas Wolff
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