From: Heesob Park <redmine@...>
Date: 2010-01-03T12:31:01+09:00
Subject: [ruby-core:27376] [Bug #2549] Redirected stdout don't work on child process on Windows

Bug #2549: Redirected stdout don't work on child process on Windows
http://redmine.ruby-lang.org/issues/show/2549

Author: Heesob Park
Status: Open, Priority: Normal
ruby -v: ruby 1.9.1p243 (2009-07-16 revision 24175) [i386-mingw32]

A file created in Ruby and redirected to stdout don't work properly on child process in 1.9.x.

c:\work>type test.rb
STDOUT.reopen(File.open('out.txt', 'w+')) 
system('ruby -v')
File.open('out.txt','a+'){|f|f.puts('EOF')}
 
In 1.8.6
c:\work>type out.txt
ruby 1.8.6 (2009-08-04 patchlevel 383) [i386-mingw32]
EOF

In 1.9.1p243 and 1.9.2dev
c:\work>type out.txt
EOF

I noticed the root cause is FILE_FLAG_OVERLAPPED handling of
ruby 1.9.x. I guess it is related with the select and native thread supporting
on Windows. But the child process cannot handle the overlapped
I/O on most cases.

In short, the inheritable file handle must not opened with the
FILE_FLAG_OVERLAPPED flag.

Regards,
Park Heesob


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