Hi Bin,
On 3/1/2013 5:17 PM, goon83 wrote:
Hi, Mohamad,
Thanks for your information. I am starting writing my own
plugin right now. I am confused by two functions in the example code
you shared with me.
The first one is in :
--------------------
under_fapl = H5Pcreate (H5P_FILE_ACCESS);
H5Pset_fapl_native(under_fapl);
--------------------
what does the actually means of H5Pset_fapl_native? Why we
need these two statements for the log vol plugin.
Well that log plugin here does a printf() to "log" the operation, then
calls the native HDF5 plugin to execute the VOL operation. So we are
stacking 2 plugins in this case. First the call goes through the log
plugin and the log plugin then uses the under_fapl to send it to the
native plugin.
The second one is in:
---------
acc_tpl = H5Pcreate (H5P_FILE_ACCESS);
H5Pset_vol(acc_tpl, vol_id, &under_fapl);
file_id = H5Fcreate(file_name, H5F_ACC_TRUNC, H5P_DEFAULT,
acc_tpl);
---------
Does H5Pset_vol build the relationship between the acc_tpl
and vol_id ? If it is YES, does the next function H5Fcreate means that
if we create a file with acc_tpl property, the request on this file
will handled by the vol with vol_id ?
yes, yes.
BTW, why we need under_fapl in H5Pset_vol, would you mind explain to me?
as explained above, the under_fapl here is information for the log
plugin to know where to send the other call. If you don't want to send
the call to the native plugin in this case, you could pass NULL. Please
note that the example I sent you shows how to stack two plugin. If you
are just writing your own plugin, you shouldn't worry about using the
native plugin here, and pass the info you need (NULL if you don't need
any) in the set_vol call.
Thanks,
Mohamad
Thanks.
Bin
--
365???? <http://gongyi.163.com/love365>
At 2013-01-08 23:24:14,"Mohamad Chaarawi" <[email protected]> wrote:
Hi Bin,
The VOL work is not part of any release yet and still sitting in a
separate branch. We are aiming to release with 1.10.
You can access the branch from:
http://svn.hdfgroup.uiuc.edu/hdf5/features/vol
I have to warn you that this is not a release branch, but a
development branch, so things will change in the future. The VOL
interface has been stable for a while now, however with some
changes/additions expected to the HDF5 library interface, the VOL
interface callbacks will change.
I also attached a sample C file that serves as a guide for adding
an external plugin. The H5VLnative.c under src/ would serve as a
guide for implementing an internal library specific plugin (which
I don't think would be your case).
Thanks,
Mohamad
On 1/7/2013 10:43 PM, goon83 wrote:
Hi all,
I am planing to conduct some research on I/O optimization
like "A Plugin for HDF5 using PLFS for Improved I/O Performance
and Semantic Analysis", and I need to write a plugin for
"Virtual Object Layer". I have already downloaded and installed
the hdf5-1.8.10 source code. However, I have not found
anyplace/guide to start a new plugin. Would you all please
give me some guide or help ? Thanks in advance !
Bin Dong
--
365???? <http://gongyi.163.com/love365>
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_______________________________________________
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
