From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <zsh-users-return-17779-mason-zsh=primenet.com.au@zsh.org>
Received: (qmail 13016 invoked by alias); 25 Apr 2013 18:27:23 -0000
Mailing-List: contact zsh-users-help@zsh.org; run by ezmlm
Precedence: bulk
X-No-Archive: yes
List-Id: Zsh Users List <zsh-users.zsh.org>
List-Post: <mailto:zsh-users@zsh.org>
List-Help: <mailto:zsh-users-help@zsh.org>
X-Seq: 17779
Received: (qmail 15684 invoked from network); 25 Apr 2013 18:27:20 -0000
X-Spam-Checker-Version: SpamAssassin 3.3.2 (2011-06-06) on f.primenet.com.au
X-Spam-Level: 
X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,RCVD_IN_DNSWL_NONE
	autolearn=ham version=3.3.2
Received-SPF: none (ns1.primenet.com.au: domain at closedmail.com does not designate permitted sender hosts)
From: Bart Schaefer <schaefer@brasslantern.com>
Message-id: <130425112711.ZM17317@torch.brasslantern.com>
Date: Thu, 25 Apr 2013 11:27:11 -0700
In-reply-to: <klbq25$osh$1@ger.gmane.org>
Comments: In reply to "Yuri D'Elia" <wavexx@users.sourceforge.net>
 "Re: precmd: write error: interrupted" (Apr 25,  7:44pm)
References: <klbmnc$ieh$1@ger.gmane.org>  <klbq25$osh$1@ger.gmane.org>
X-Mailer: OpenZMail Classic (0.9.2 24April2005)
To: zsh-users@zsh.org
Subject: Re: precmd: write error: interrupted
MIME-version: 1.0
Content-type: text/plain; charset=us-ascii

On Apr 25,  7:44pm, Yuri D'Elia wrote:
}
} On 04/25/2013 06:47 PM, Yuri D'Elia wrote:
} > 2) Why "precmd() { { print "HELLO" } >&- 2>&-; } doesn't suppress the
} > error in this case?
} 
} Closest analogue I could find is:
} 
} % { { print >&2 } 2>&- } 2>/dev/null
} zsh: write error

Of course what's happening here is in outside-in order.  Starting with
the stuff you can mostly see:

1. stderr is redirected to /dev/null (old stderr is saved)
2. stderr is closed (at this point the outer redirection is gone)
3. print generates an error

Now the stuff you can't see happens:

4. zsh gets another error writing to the closed stderr
5. zsh warns about that to the saved stderr from step 1

You avoid the whole mess if you never close stderr, or if you close it
before step 1 (e.g. by "exec 2>&-"), though the latter is impractical
in the case we're discussing.