How to tell a file is locked wityout opening (very fast)

[IndikaNiva]

Hi,

I need to find if a file is locked, but I dont want to open the file as I will be checking 1000's of files.

can I do that in C++ or VC++

Thanks


ps... here after a long time.

[2kaud]

If you just want to know which files are open, have a look at
http://technet.microsoft.com/en-us/s...rnals/bb896655

[IndikaNiva]

Thanks for the reply, Not exactly.
I have a list of files, I want to move them to a server, so before the process begins, I want to know if any one of those files are locked by another process. It has to be very fast, that is why dont want to open each file to see if I can obtain an exclusive open.

Thanks

[IndikaNiva]

from my C++ code, I can also use MFC in my code.

[2kaud]

The program 'handle' for which I gave the link will display those files which are 'open' ie cannot be moved. It is very quick. The way I do something similar to what you want to do is to redirect the output of this program into a text file which I then parse to get the file names which I store in a set. For the files I want to process, I first check if the name appears in this set and if it doesn't the file is OK to process. If the name does appear, then it isn't OK to process as the file is open by a process.

[IndikaNiva]

seems like a lot of overhead for what I want to do, this also means I have to ship this program now.
Thanks... I was hoping for some API call to see if the file is locked

[OReubens]

There is no easy/Obvious simple solution for this other than opening the file.

What the "handle" tool does (source is available on sysinternals) is the closest you can get if "file is opened" is all you're interested in.
if you want to know "file is opened and has locked ranges" it becomes considerably more difficult.

[2kaud]

(source is available on sysinternals)

Have you got a link to these sources? The source for some of sysinternals programs used to be available but I thought the sources had been removed a while ago?

[VladimirF]

I have a list of files, I want to move them to a server, so before the process begins, I want to know if any one of those files are locked by another process. It has to be very fast, that is why dont want to open each file to see if I can obtain an exclusive open.

Could you please clarify: if *ANY* of the files are locked you will not move the other ones too?
In that case you would have to lock the files yourself, or else they might get locked after your check but before the move.

[OReubens]

Have you got a link to these sources? The source for some of sysinternals programs used to be available but I thought the sources had been removed a while ago?

Aw, hadn't noticed that they removed it all. It's been a while I last wanted any of the sourcecode (I have gotten newer tools versions).

Google is your friend, plenty mirrors have the old sources.

[2kaud]

OK. Found some source. To determine files that are locked the code uses some deep API functions that are not usually exported and to which the code has to dynamically link (eg NtQuerySystemInformation etc) and whose returned structures can change from one version to the next. I wouldn't like to have to maintain code like this for a production program!