All the best,
Samer
On 19.07.2015 16:37, Werner Benger wrote:
Hi Samer,
if those applications are linking dynamically with HDF5, you could
interface there by providing a "patched" version of HDF5 that is binary
compatible, but still performs some file locking, possibly via a modified
VFD.
Just checking the file sizes won't be a sure check, in particular it would
not work for and application that does not append data but modifies
existing ones. You should be able to check the "last modified" date on the
file as well, and if the HDF5 file cannot be opened by another application,
then it's either corrupted or still open and data written to it.
It should also be possible to find out which process has file handles to a
specific file open, both Linux and Windows seem to allow that, just in an
OS-specific way:
Finding open file descriptors for a process linux ( C code )? - Stack Overflow
Process Explorer - Sysinternals | Microsoft Learn
It may require your program to run under admin rights though.
Cheers,
Werner
On 19.07.2015 12:32, Samer Afach wrote:
Dear Werner:
Unfortunately I don't have the source of the writing program. It could be
anything actually; labview, C, C++, etc... . I'm working on a collaborative
program for collecting data, and my software is supposed to upload the data
to the main storage server for backup and data analysis. Everyone is free
to use any tools they want for data acquisition.
Is there any solution to my problem that doesn't involve me having
authority on the writing program? Currently I'm using a method that I
invented, where I measure the size of the file multiple times, and if the
size doesn't change for some time, then that decide that the file isn't
being written... that's the only way I could come up with, but this has
nothing to do with HDF5.
All the best,
Samer
On 19.07.2015 12:23, Werner Benger wrote:
Hi Samer,
do you have full source code access to both programs, the one writing the
file and the one uploading it?
If so, would adding some file locking mechanism (
<https://en.wikipedia.org/wiki/File_locking>
File locking - Wikipedia ) help your case?
Cheers,
Werner
On 19.07.2015 02:50, Samer Afach wrote:
Dear Werner:
Thank you for your response and your time.
I tried modifying the source code of h5check, but it's very complicated
and returns strings instead of error codes. Besides, I tried to compile it
by including the three files in the main c file and it gave errors that
don't seem to be easily trackable. It'll take me lots of time to prepare
something reliable out of it with full testing. I wonder why the hdf group
didn't implement such a functionality in low language, I thought it exists
and I can't find it. 
About my second question, apparently I wasn't clear on what I really need
and I was misunderstood. What I need is to check whether the file I want to
read is being accessed by some other program. My problem is that the file I
wanna deal with is being written by some other program, and I want to
initiate an upload after it's done writing. So I would like to check
whether the other program is finished writing and closed it before I send
it to my upload queue.
All the best,
Samer
On 18.07.2015 23:11, Werner Benger wrote:
Hi Samer,
On 18.07.2015 16:23, Samer Afach wrote:
Dear pros:
I have two similar issues I would like to ask about, and I'd be grateful
if you could help me:
1- How can I check HDF5 file integrity in C/C++ (I prefer low level C)? I
know there's a software called h5check, but I need a function to do that,
not a software. In my application, it's not an option to execute h5check
from my system.
Is there any objection against you taking the source code of h5check,
rename the main function to h5check_main() and then call it as C function
from your code?
2- How can I do a quick check in C/C++ to see whether the file is being
written/modified/open for write? I looked in this link
<https://www.hdfgroup.org/HDF5/doc/H5.format.html#FileMetaData> which
discusses metadata, but there doesn't seem to be a clear way through the
C/C++ interface for me a to read the first two bits that give me that
information. Could you please help with that with a simple example?
This sounds as if you want to know what the HDF5 library is currently
doing with a file? Well what you could do is to modify the virtual file
driver that you want to use, and let it keep track of that happens with the
file. It's the VFD that does the actual writing of a file content, so you
can trace its write() call to keep track what exactly happens when. It's
some effort of course.
Cheers,
Werner
All the best,
Samer
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___________________________________________________________________________
Dr. Werner Benger Visualization Research
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--
___________________________________________________________________________
Dr. Werner Benger Visualization Research
Center for Computation & Technology at Louisiana State University (CCT/LSU)
2019 Digital Media Center, Baton Rouge, Louisiana 70803
Tel.: +1 225 578 4809 Fax.: +1 225 578-5362
_______________________________________________
Hdf-forum is for HDF software users discussion.Hdf-forum@lists.hdfgroup.orghttp://lists.hdfgroup.org/mailman/listinfo/hdf-forum_lists.hdfgroup.org
Twitter: x.com
_______________________________________________
Hdf-forum is for HDF software users discussion.Hdf-forum@lists.hdfgroup.orghttp://lists.hdfgroup.org/mailman/listinfo/hdf-forum_lists.hdfgroup.org
Twitter: x.com
--
___________________________________________________________________________
Dr. Werner Benger Visualization Research
Center for Computation & Technology at Louisiana State University (CCT/LSU)
2019 Digital Media Center, Baton Rouge, Louisiana 70803
Tel.: +1 225 578 4809 Fax.: +1 225 578-5362
_______________________________________________
Hdf-forum is for HDF software users discussion.Hdf-forum@lists.hdfgroup.orghttp://lists.hdfgroup.org/mailman/listinfo/hdf-forum_lists.hdfgroup.org
Twitter: x.com
_______________________________________________
Hdf-forum is for HDF software users discussion.
Hdf-forum@lists.hdfgroup.org
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