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Re: 12.2: fork() causing getline() to repeat stdin endlessly

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On Tue, Oct 24, 2023 at 11:01:55PM +0700, Max Nikulin wrote:
> On 24/10/2023 12:18, tom kronmiller wrote:
> > so I unbuffered stdin and that seemed to make it happy.
> 
> It might be performance killer. Even fflush(NULL) before fork() may be
> better.
> 
> https://stackoverflow.com/questions/50110992/why-does-forking-my-process-cause-the-file-to-be-read-infinitely
> "Why does forking my process cause the file to be read infinitely"

Ooh, that's got an *excellent* answer.

> glibc bug report was closed as invalid
> https://sourceware.org/bugzilla/show_bug.cgi?id=23151
> 
> I am curious why macOS behaves differently.

It would have been nice if the glibc developer had explained a bit, but
of course we aren't owed any explanations.

At this point, we can conclude that the bug is in fact in the OP's C
program.  The underlying C compiler, C library, and Linux kernel are
all behaving within specs.

At this point I still don't know *why* glibc rewinds stdin intermittently
on exit().  Apparently Mac OS X doesn't, or at least didn't at the time
the answer was written (2018).  I guess there must be some reason for it,
and it's not just randomly pranking people, even if I don't understand
the reason.

This has been a most educational thread.

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Re: 12.2: fork() causing getline() to repeat stdin endlessly "Thomas Schmitt" <scdbackup@gmx.net> - 2023-10-23 10:50 +0200
  Re: 12.2: fork() causing getline() to repeat stdin endlessly "Thomas Schmitt" <scdbackup@gmx.net> - 2023-10-23 11:20 +0200
    Re: 12.2: fork() causing getline() to repeat stdin endlessly Greg Wooledge <greg@wooledge.org> - 2023-10-23 15:40 +0200
      Re: 12.2: fork() causing getline() to repeat stdin endlessly jleonard@slimy.com (Jon Leonard) - 2023-10-23 16:20 +0200
        Re: 12.2: fork() causing getline() to repeat stdin endlessly tom kronmiller <twk.personal@gmail.com> - 2023-10-23 16:40 +0200
          Re: 12.2: fork() causing getline() to repeat stdin endlessly Greg Wooledge <greg@wooledge.org> - 2023-10-23 17:20 +0200
        Re: 12.2: fork() causing getline() to repeat stdin endlessly gene heskett <gheskett@shentel.net> - 2023-10-23 18:40 +0200
          Re: 12.2: fork() causing getline() to repeat stdin endlessly <tomas@tuxteam.de> - 2023-10-23 20:10 +0200
    Re: 12.2: fork() causing getline() to repeat stdin endlessly tom kronmiller <twk.personal@gmail.com> - 2023-10-23 21:50 +0200
      Re: 12.2: fork() causing getline() to repeat stdin endlessly "Thomas Schmitt" <scdbackup@gmx.net> - 2023-10-23 22:20 +0200
        Re: 12.2: fork() causing getline() to repeat stdin endlessly Greg Wooledge <greg@wooledge.org> - 2023-10-23 22:30 +0200
          Re: 12.2: fork() causing getline() to repeat stdin endlessly "Thomas Schmitt" <scdbackup@gmx.net> - 2023-10-23 22:50 +0200
            Re: 12.2: fork() causing getline() to repeat stdin endlessly Greg Wooledge <greg@wooledge.org> - 2023-10-23 23:00 +0200
        Re: 12.2: fork() causing getline() to repeat stdin endlessly tom kronmiller <twk.personal@gmail.com> - 2023-10-24 07:20 +0200
          Re: 12.2: fork() causing getline() to repeat stdin endlessly Max Nikulin <manikulin@gmail.com> - 2023-10-24 18:10 +0200
            Re: 12.2: fork() causing getline() to repeat stdin endlessly Greg Wooledge <greg@wooledge.org> - 2023-10-24 21:30 +0200
              Re: 12.2: fork() causing getline() to repeat stdin endlessly conover@panix.com (John Conover) - 2023-10-25 01:00 +0200
              Re: 12.2: fork() causing getline() to repeat stdin endlessly jleonard@slimy.com (Jon Leonard) - 2023-10-25 04:20 +0200
              Re: 12.2: fork() causing getline() to repeat stdin endlessly Max Nikulin <manikulin@gmail.com> - 2023-10-25 04:40 +0200
              Re: 12.2: fork() causing getline() to repeat stdin endlessly <tomas@tuxteam.de> - 2023-10-25 06:30 +0200
            Re: 12.2: fork() causing getline() to repeat stdin endlessly tom kronmiller <twk.personal@gmail.com> - 2023-10-25 07:40 +0200
              Re: 12.2: fork() causing getline() to repeat stdin endlessly tom kronmiller <twk.personal@gmail.com> - 2023-10-25 08:00 +0200
  Re: 12.2: fork() causing getline() to repeat stdin endlessly Max Nikulin <manikulin@gmail.com> - 2023-10-23 18:30 +0200
    Re: 12.2: fork() causing getline() to repeat stdin endlessly Stefan Monnier <monnier@iro.umontreal.ca> - 2023-10-24 05:00 +0200

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