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Re: Flush stdin

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Cameron Simpson <cs@zip.com.au>:

> Even if nc itself does no buffering (handing data to the OS as soon as
> received, highly desirable for a tool like nc), the OS keeps a buffer
> for the pipeline between nc and python,

Yes, there is a buffer associated with the pipe, but linux/unix never
withholds any data from the reader. As soon as there is a single byte in
the pipe buffer, the reader process becomes ready to run and read(2) on
the pipe returns immediately.

> and python itself keeps a buffer for sys.stdin.

I found this comment in CPython's source code (pythonrun.c):

    /* stdin is always opened in buffered mode, first because it shouldn't
       make a difference in common use cases, second because TextIOWrapper
       depends on the presence of a read1() method which only exists on
       buffered streams.
    */

The solution is to use os.read().


Marko

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Re: Flush stdin Cameron Simpson <cs@zip.com.au> - 2014-10-20 14:56 +1100
  Re: Flush stdin Marko Rauhamaa <marko@pacujo.net> - 2014-10-20 07:45 +0300
    Re: Flush stdin Dan Stromberg <drsalists@gmail.com> - 2014-10-20 14:59 -0700
      Re: Flush stdin Marko Rauhamaa <marko@pacujo.net> - 2014-10-21 01:54 +0300
    Re: Flush stdin Dan Stromberg <drsalists@gmail.com> - 2014-10-20 15:52 -0700
      Re: Flush stdin Marko Rauhamaa <marko@pacujo.net> - 2014-10-21 02:18 +0300
        Re: Flush stdin Dan Stromberg <drsalists@gmail.com> - 2014-10-20 17:30 -0700
          Re: Flush stdin Marko Rauhamaa <marko@pacujo.net> - 2014-10-21 07:41 +0300
            Re: Flush stdin Dan Stromberg <drsalists@gmail.com> - 2014-10-21 16:16 -0700
              Re: Flush stdin Marko Rauhamaa <marko@pacujo.net> - 2014-10-22 08:38 +0300
                Re: Flush stdin Chris Angelico <rosuav@gmail.com> - 2014-10-22 17:23 +1100
              Re: Flush stdin Marko Rauhamaa <marko@pacujo.net> - 2014-10-22 13:57 +0300
            Re: Flush stdin random832@fastmail.us - 2014-10-22 11:01 -0400
              Re: Flush stdin Marko Rauhamaa <marko@pacujo.net> - 2014-10-22 18:28 +0300

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