Sv: Named pipes and multiple writers
Norton Allen
allen@huarp.harvard.edu
Thu Mar 26 17:00:20 GMT 2020
On 3/26/2020 12:44 PM, Ken Brown via Cygwin wrote:
> On 3/26/2020 12:03 PM, Norton Allen wrote:
>> On 3/26/2020 11:11 AM, Ken Brown via Cygwin wrote:
>>>
>>> BTW, I've been working on adding support for multiple readers. I
>>> expect to have a first cut ready within a week or two. Would you
>>> have any use for that? If so, I could revive the topic/fifo branch
>>> and push my patches there for you to test.
>>>
>>
>> Ken, what are the semantics for multiple readers? Do all readers see
>> the same data, or is it first come first served or something else?
>
> It's first come, first served. If two readers attempt to read
> simultaneously, it's possible that one will get some of the available
> input and the other will get some more.
>
> The only use case for multiple readers that I've come across of is
> Midnight Commander running under tcsh. I didn't dig into the code
> enough to know why they do it, or why only under tcsh. See
>
> https://sourceware.org/pipermail/cygwin/2019-December/243317.html
>
> and
>
> https://cygwin.com/pipermail/cygwin-apps/2019-December/039777.html
>
> That's what got me interested in this. It would be nice to know if
> there are other use cases.
>
I suppose it could be used as a simple approach to deploying jobs to
worker processes, provided a process could guarantee that it received
enough information to define a job and not more than one. I guess if the
job definition were fixed length that could work.
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