Re: opensm/main.c: foce stdout to be line-buffered

[Yevgeny Kliteynik <kliteyn-LDSdmyG8hGV8YrgS2mwiifqBs+8SCbDb@public.gmane.org>]

On 23/Mar/10 18:37, Sasha Khapyorsky wrote:
> On 14:25 Tue 23 Mar     , Yevgeny Kliteynik wrote:
>>
>> I'm running "opensm>  somefile", and I don't see SM's stdout
>> (such as "SUBNET UP" message, or new cached options after SIGHUP),
>> because when stdout is assigned to file and not terminal, it is
>> handled differently. Instead of flushing on printing '\n',
>> it becomes buffered, which means that you don't control when
>> is this buffer flushed.
>> My fix forces stdout to always flush stdout when printing '\n'.
>> It has no effect when stdout is assigned to terminal, and it
>> changes buffering when SM's stdout is redirected.
>>
>> More details about stdout/stderr buffering:
>>
>> http://www.pixelbeat.org/programming/stdio_buffering/
>
> There you can find couple of ways to workaround this issue, for example:
>
>    stdbuf -o L opensm>  somefile

This is not a usual shell command, nor some common
tool that is used in Linux distros. It's just a tool
that is provided in some package called "coreutils 7.5".
  
> I would prefer to not change an external settings so the program would
> work as expected.

IMHO, on the contrary - the expected behavior
would be achieved with the patch.

But in any case, what exactly seems problematic here?

I can't see any impact on any aspect whatsoever.
It is somehow related to performance (more flushes
when the stream is line-buffered instead of just
buffered), but we're talking about stdout here, not
the log file, so the performance is not affected too.

-- Yevgeny
  
> Sasha
>

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