Fwd: is file open in system ? - other than lsof

[bvidinli]

Here is (hope) complete info for my question:
i use linux/unix
i use python 2.3

my subject is a single file at a time. but i have to check thousands
of files in a loop.
so, since there is thousands of files to process, i dont want to use
like os.system('lsof filename')
because lsof is slow regarding, when you called it thousands of times.

is there another way, any python command sequence that i can check if
a file is open at the time of "before i process file"

i am not interested in " the file may be written after i access it.."
the important point is " the time at i first access it."

my routine is something like:
for i in listoffiles:
checkfileopen(i)
processfile()

thats it...

i hope this will clear my question..
thank you a lot.

---------- Forwarded message ----------
From: Chris McAloney <mcaloney at gmail.com>
Date: 16.Nis.2008 17:00
Subject: Re: is file open in system ? - other than lsof
To: python-list at python.org


On 16-Apr-08, at 9:20 AM, A.T.Hofkamp wrote:
 > On 2008-04-16, bvidinli <bvidinli at gmail.com> wrote:
 >> is there a way to find out if file open in system ? -
 >> please write if you know a way  other than lsof. because lsof if
 >> slow for me.
 >> i need a faster way.
 >> i deal with thousands of files... so, i need a faster / python way
 >> for this.
 >> thanks.
 >
 > This is not a Python question but an OS question.
 > (Python is not going to deliver what the OS doesn't provide).
 >
 > Please first find an alternative way at OS level (ie ask this
 > question at an
 > appropiate OS news group). Once you have found that, you can think
 > about Python
 > support for that alternative.

 I agree with Albert that this is very operating-system specific.
 Since you mentioned 'lsof', I'll assume that you are at least using a
 Unix variant, meaning that the fcntl module will be available to you,
 so you can check if the file is already locked.

 Beyond that, I think more information on your application would be
 necessary before we could give you a solid answer.  Do you only need
 to know if the file is open, or do you want only the files that are
 open for writing?  If you only care about the files that are open for
 writing, then checking for a write-lock with fcntl will probably do
 the trick. Are you planning to check all of the "thousands of files"
 individually to determine if they're open?  If so, I think it's
 unlikely that doing this from Python will actually be faster than a
 single 'lsof' call.

 If you're on Linux, you might also want to have a look at the /proc
 directory tree ("man proc"), as this is where lsof gets its
 information from on Linux machines.

 Chris

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İ.Bahattin Vidinli
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