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bug#37564: [PATCH] don't export LINES and COLUMNS env vars in term to fi
From: |
Eli Zaretskii |
Subject: |
bug#37564: [PATCH] don't export LINES and COLUMNS env vars in term to fix ncurses applications |
Date: |
Tue, 21 Jan 2020 19:11:26 +0200 |
> From: Glenn Morris <rgm@gnu.org>
> Cc: Stefan Kangas <stefan@marxist.se>, matthew@mattleach.net,
> 37564@debbugs.gnu.org
> Date: Mon, 20 Jan 2020 19:58:53 -0500
>
>
> No other terminal emulator exports LINES and COLUMNS as environment variables.
Maybe so, but that in itself doesn't yet mean Emacs cannot do that, if
we decide it's useful.
> Applications use ioctl to get the size.
> -> Therefore setting LINES and COLUMNS is pointless.
> If LINES/COLUMNS are set, they override ioctl.
Is the last bit a generally accepted paradigm? I could easily justify
the contrary preference.
And then there might be applications that don't use ioctl.
> You can't update the environment of an already running process.
> Therefore the presence of LINES/COLUMNS in the initial environment
> of a process spawned from Emacs means it will fail to react to resizing.
> Therefore exporting LINES and COLUMNS is harmful.
Only if the application uses the variables in preference to ioctl.
> So don't export LINES and COLUMNS.
I agreed at the very beginning of the discussion to make the export
optional. I don't think we can safely remove that unconditionally,
not yet.