[gdal-dev] VSI issue

[Frank Broniewski]

Am 20.11.2011 10:04, schrieb Ari Jolma:
> On 11/19/2011 04:24 PM, Even Rouault wrote:
>>> I found the problem. It is changeset 23022 (by you, Even :), which
>>> removes support for "stdout" and adds "/dev/stdout" as an alias to
>>> "/vsistdout/". Simple, but took me a while to find out especially as the
>>> log message begins "mentions in the doc".
>> Hum, so it means that under your CGI the stdout file is actually closed.
>> Because before r23022 /dev/stdout was considered as a regular file and
>> was
>> opened, but now that /vsistdout/ is used, it directly writes to FILE*
>> stdout.
>>
>> I don't know Apache but perhaps there's an option to leave stdout
>> opened for
>> the forked process ?
>
> I think the correct thing to do is to use "/vsistdout/" in CGI programs,
> since it works both in older (1.8.0) and newer GDAL (next release).
>
> Ari
>
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I can only speak for python, but I agree with Ari here. Mod_wsgi, the 
python - apache module advises also not to use /dev/stdout because it is 
used internally to communicate with the webserver, [1] holds more 
explanation on the issue.
And I don't know, how far you could use /dev/stdout in threaded 
environments like a webserver without having more than one thread 
writing to the same /dev/stdout.

Just my additional 2 cents on the stdout - issue ;-)

Frank


[1] 
http://code.google.com/p/modwsgi/wiki/ApplicationIssues#Writing_To_Standard_Output

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Frank BRONIEWSKI

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