[Newbies] Re: PipeableOSProcess incremental output

David T. Lewis lewis at mail.msen.com
Sat Nov 26 16:27:01 UTC 2011

On Sat, Nov 26, 2011 at 07:40:42AM -0800, Sean P. DeNigris wrote:
> Sean P. DeNigris wrote
> > 
> > I got a little further. #updateErrorPipelineStream helped to get the error
> > messages as they came.
> > 
> Dave, based on your answers, this seems like it should not be necessary, yet
> without it #errorUpToEnd returned an empty string even though there was
> output available. Is there an internal flush that's not getting done?

PipeableOSProcess is designed to be used in a pipeline of connected
process proxies (or other types of PipeJunction). In that context,
The standard output of each PipeJunction is connected to the standard
input of the next, and the error output (if any) from each PipeJunction
needs to go somewhere. The errorPipelineStream is shared by multiple
process proxies in the pipeline, and provides a place to accumulate
the error output from any of the process proxies. The updates to this
accumulator stream are triggered by change notifications that happen
as data becomes available on the error output streams of each process


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