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Re: /dev/stderr problem
- From: Linda Walsh <cygwin at tlinx dot org>
- To: cygwin at cygwin dot com
- Date: Mon, 17 Oct 2016 11:00:36 -0700
- Subject: Re: /dev/stderr problem
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Eric Blake wrote:
On 10/17/2016 01:32 AM, Thorsten Kampe wrote:
* Thorsten Kampe (Mon, 17 Oct 2016 08:25:13 +0200)
the following bash script results in a different output when
redirected to a file.
printf "FIRST LINE\n" > /dev/stderr
shopt -os xtrace
printf "SECOMD LINE\n" > /dev/stderr
Cygwin treats '> /dev/stderr' as a request to truncate /dev/stderr (or,
for that matter, any opening of a file under /proc/self/fd). Other
platforms treat that as a special file that can never be truncated, but
is instead reopened at the same offset.
Maybe cygwin can be taught that opening a file through /proc/self/fd
should preserve rather than reset offsets, but it will be a tricky
patch, and someone has to write it.
Is /dev/stderr a POSIX special name that one should expect that rewinding
is disallowed or ignored?
Good analysis, BTW, that sure would have puzzled me.
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