Does read-only HDF usage tolerate multi-threading? I was under the
impression that enabling threading simply added a mutex around critical
operations. Is there a difference between platforms, e.g. Linux & Windows?

Cheers,

Sebastian

On Thu, Jul 8, 2010 at 6:00 AM, Quincey Koziol <[email protected]> wrote:

> Hi Richard,
>
> On Jul 7, 2010, at 3:47 AM, Richard Khoury wrote:
>
> > Hello,
> > After writing an application that allows the user to flip between loading
> and saving a H5 file, a few objects within the file weren't closing properly
> which didn't allow the file to close when I called H5Fclose. Going from a
> loading state (H5open) to a saving state (H5create or H5open with RDWR
> access) complained that the file was still open so I implemented a simple
> routine to close all open objects within a file before calling H5Fclose:
> >
> >   void close_all_objects_within_file (hid_t file_id)
> >   {
> >     ssize_t numOpenObjs = H5Fget_obj_count(file_id, H5F_OBJ_ALL);
> >     hid_t *obj_id_list = (hid_t*)(malloc(numOpenObjs * sizeof(hid_t)));
> >     ssize_t numReturnedOpenObjs = H5Fget_obj_ids(file_id, H5F_OBJ_ALL,
> numOpenObjs, obj_id_list);
> >     for (ssize_t i = 0; i < numReturnedOpenObjs; ++i)
> >     {
> >       H5Oclose(obj_id_list[i]);
> >     }
> >     free(obj_id_list);
> >   }
> >
> > This worked fine until the application became multi-threaded, and a call
> to close_all_objects_within_file(file_id) was crashing the program. It seems
> that the object resources are shared between the threads that have opened
> the same file, and the first thread to call this routine kills any chance of
> another thread to use that resource. Is this correct?
>
>         Yes.
>
> > If this is case, is there a way I can check (in the for-loop above) if
> the object is being referenced by another thread before doing an H5Oclose?
> Or perhaps there's a better way to close all the resources of a file? Or
> maybe I'm going about this the wrong way, in which case I'm very much open
> to suggestions.
>
>         You probably want to use the H5Pset_fclose_degree() routine.
>
>                Quincey
>
>
> _______________________________________________
> Hdf-forum is for HDF software users discussion.
> [email protected]
> http://mail.hdfgroup.org/mailman/listinfo/hdf-forum_hdfgroup.org
>
_______________________________________________
Hdf-forum is for HDF software users discussion.
[email protected]
http://mail.hdfgroup.org/mailman/listinfo/hdf-forum_hdfgroup.org

Reply via email to