The advantage of allowing C++ allocation methods via callbacks would be
that you can have one piece of code which retrieves data from an HDF5
file and then forget about the HDF5 file (and library) while still
operating on the data, without need to copy C-allocated memory into
C++-allocated memory. In general, anything that allows to avoid copying
data would be good, though for these kind of data here it's probably not
going to be a performance bottleneck. It could rather be some advanced
functionality for the rare situations where it would be of relevance,
maybe something that can be embedded into some property lists.
Werner
On 25.03.2014 15:09, Dana Robinson wrote:
This is a C library issue, not C++, so we don't have new operators or
std::vectors.
While that's an interesting idea, I'd argue that providing a simple
free function to users is a much easier and more direct solution.
Dana
*From:*Hdf-forum [mailto:[email protected]] *On
Behalf Of *Werner Benger
*Sent:* Monday, March 24, 2014 5:02 PM
*To:* HDF Users Discussion List
*Subject:* Re: [Hdf-forum] RFC: Freeing Memory Allocated by the HDF
Library
Looks all good to me.
As a possible alternative to the two-function call version to allocate
memory, options might also be to define something like a "memory
manager" which contains a structure of function calls that do
allocation/freeing, or just passing such a memory allocation function
to those HDF5 functions that need to allocate memory. That way you
could have a single HDF5 function call using a user-defined function
to allocate memory, for instance a function allocating via the C++ new
operator or putting data into a C++ std::vector<> object. This however
comes with some danger of C++ exceptions being thrown in such an
allocation function, so it at least needs to be documented how to deal
with such situations.
Werner
On 24.03.2014 19:34, Dana Robinson wrote:
Hi all,
This is a brief RFC that outlines a new HDF5 API function,
H5free_memory(), which can be used to free memory returned from
the HDF5 library (e.g., via functions like H5Tget_member_name()).
This will be of particular interest to Windows users, since this
will help mitigate the problems of linking to multiple versions of
the C runtime.
The new function will appear in HDF5 1.8.13, which will be
released in May.
If anyone has any comments or concerns, please let us know.
Cheers,
Dana
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Hdf-forum is for HDF software users discussion.
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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.
[email protected]
http://mail.lists.hdfgroup.org/mailman/listinfo/hdf-forum_lists.hdfgroup.org
--
___________________________________________________________________________
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.
[email protected]
http://mail.lists.hdfgroup.org/mailman/listinfo/hdf-forum_lists.hdfgroup.org
