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From: Yuri D'Elia <wavexx@users.sourceforge.net>
Subject: Re: precmd: write error: interrupted
Date: Thu, 25 Apr 2013 22:05:41 +0200
Message-ID: <klc2ah$jiv$1@ger.gmane.org>
References: <klbmnc$ieh$1@ger.gmane.org> <130425111646.ZM17258@torch.brasslantern.com>
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In-Reply-To: <130425111646.ZM17258@torch.brasslantern.com>

On 04/25/2013 08:16 PM, Bart Schaefer wrote:
> } 1) SIGWINCH should either be masked or allow write to restart.
>
> This requires some thought about the appropriate layer to handle this.
> bin_print does already do some signal queuing when writing to internal
> data structures (print -z, print -s), but that's deliberately isolated
> to bin_print, whereas all sorts of other things might write to the
> terminal -- including other error messages! -- so patching bin_print is
> not covering all the bases.

I actually tried to set SA_RESTART only when installing the handler for 
SIGWINCH when debugging [1]. It works in this case, but I'm not entirely 
sure it is side-effect free (is doing an ioctl on the tty safe while 
mid-write?).

What other syscalls would be interrupted by SIGWINCH that shouldn't be 
restarted? Right now I cannot think of anything that SIGWINCH should 
interrupt.

You can actually reproduce the bug easily by doing:

while print 'x'; do; done

and resizing the terminal, or by sending SIGWINCH to zsh directly.

[1] interestingly enough, why "interact" is tested for the Sunos4 case?