[racket] custom port question

From: Robby Findler (robby at eecs.northwestern.edu)
Date: Fri Sep 7 01:33:49 EDT 2012

Depending on what kind of guarantees you want, there is a simpler way
than using make-output-port. You can create a pipe and then use
copy-port to duplicate the data in a separate thread. Be sure to close
the intermediate ports, tho, or else you may wait forever for the


On Fri, Sep 7, 2012 at 1:43 AM, Kartik Agaram <ak at akkartik.com> wrote:
> I'm trying to build an output port that acts like 'tee', wrapping two
> (or more) output ports and duplicating writes to them. This requires
> make-output-port
> (http://docs.racket-lang.org/reference/customport.html#%28def._%28%28quote._~23~25kernel%29._make-output-port%29%29),
> right? I'm trying to think about what the evt arg to make-output-port
> should be. It needs to be the AND of the sync-readiness of all the
> constituent ports, right? Is there a way to specify that? choice-evt
> (http://docs.racket-lang.org/reference/sync.html#%28def._%28%28quote._~23~25kernel%29._choice-evt%29%29)
> is an OR, if I'm reading the docs right..
> Thanks,
> Kartik
> http://akkartik.name
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