From: Harald van Dijk <harald@gigawatt.nl>
To: Vadim Zeitlin <vz-dash@zeitlins.org>, dash@vger.kernel.org
Subject: Re: Improving xtrace output from subshells
Date: Thu, 28 May 2020 12:57:27 +0100 [thread overview]
Message-ID: <d068031c-7ff4-22bd-4951-eeeaea278386@gigawatt.nl> (raw)
In-Reply-To: <e9cdb884-89d6-9b9d-3cb8-38b9b862aa9d@gigawatt.nl>
On 29/04/2019 23:55, Harald van Dijk wrote:
> On 29/04/2019 15:44, Vadim Zeitlin wrote:
>> On Sat, 27 Apr 2019 22:58:23 +0100 Harald van Dijk
>> <harald@gigawatt.nl> wrote:
>> HvD> It wastes memory: the code should be re-worked so that output and
>> HvD> preverrout share the same buffer, given that there can never be
>> pending
>> HvD> output for one when the other is being written to.
>>
>> I'm a bit worried about this one, it doesn't seem completely obvious
>> to me
>> that the 2 objects can't be used at the same time.
>
> It's indeed not completely obvious, but all bits that print to output
> will flush the buffer when they're done, before a next command starts
> executing, before the next command requires an xtrace string to be
> printed. It's usually the flushall() in evalbltin() that handles this.
I have managed to verify that using a single buffer for all streams
(output, errout and preverrout) works well and simplifies logic so that
the shell with that change is actually smaller than the one without it.
I do not know whether there would be interest in getting that in dash.
Cheers,
Harald van Dijk
parent reply other threads:[~2020-05-28 11:57 UTC|newest]
Thread overview: expand[flat|nested] mbox.gz Atom feed
[parent not found: <e9cdb884-89d6-9b9d-3cb8-38b9b862aa9d@gigawatt.nl>]
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