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Date:	Sun, 16 Dec 2018 17:31:32 +0100
From:	Houder <houder AT xs4all DOT nl>
To:	cygwin AT cygwin DOT com
Subject:	/dev/fd/N not synonymous with file descriptor N; it is on Linux
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L.S.,

/dev/fd/N not synonymous with file descriptor N; it is on Linux

64-@@ cat /dev/fd/0 <<\EOF
> Hi
> EOF
cat: /dev/fd/0: No such file or directory

fails on Cygwin; not on Linux.

Also see:

     https://cygwin.com/ml/cygwin/2018-12/msg00028.html
     ( Bash heredoc on FD 3 )

Based on the output of strace on Linux, I composed an STC, that 
duplicates
the steps taken by bash (and cat).

This STC succeeds on Linux, but fails on Cygwin.

What does the STC do:

  - it creates a (temporary) file in the same way that bash does
  - the file is written to, the file descriptor is closed and the file 
unlinked
  - however, before the file is unlinked, it is opened a second time, 
like bash
    would do

Next
  - the file /dev/fd/N is opened, where N is the file descriptor that has 
been
    left open; this is what the "cat command" would do.

The "cat command" on Linux succeeds; it fails on Cygwin.

Regards,
Henri

STC attached (hopefully)

=====
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