From: Joe Van Dyk <joevandyk@...>
Date: 2005-10-14T06:43:01+09:00
Subject: Re: Buffering problems

On 10/13/05, Joe Van Dyk <joevandyk@gmail.com> wrote:
> I'm trying to redirect stdout and stderr of a program to a log file.
>
> So, I'm doing something like:
>
> $stdout.sync = true
> $stderr.sync = true
> $stdout.reopen File.open(some_log_file, "w")
> $stderr.reopen File.open(some_log_file, "w")
>
> exec 'program'
>
> Standard out and error are being redirected to the log file, but they
> are being buffered.
>
> Any ideas on why that might be?

Just found IO::fsync...
--------------------------------------------------------------- IO#fsync
     ios.fsync   => 0 or nil
------------------------------------------------------------------------
     Immediately writes all buffered data in _ios_ to disk. Returns
     +nil+ if the underlying operating system does not support
     _fsync(2)_. Note that +fsync+ differs from using +IO#sync=+. The
     latter ensures that data is flushed from Ruby's buffers, but
     doesn't not guarantee that the underlying operating system actually
     writes it to disk.



I'm running on Linux.  Is there any way to force the OS to write data
from Ruby's buffers to the disk all that time?