In order to simplify the HDF5 library code and allow us to implement user-defined vlen conversions, we are considering removing the background buffer from type conversion functions. This would cause the library to issue an error if the need_bkg field in H5T_cdata_t were set to anything other than H5T_BKG_NO, always pass NULL for the bkg argument to type conversion functions, and ignore the bkg parameter for H5Pset_buffer. 1.10 may see these types and functions versioned with the aforementioned arguments removed from the new versions.
Would anyone would be affected by removing the background buffer? If so, are you supplying your own buffer to H5Pset_buffer, using the background buffer as a temporary buffer in a type conversion function (H5T_BKG_TEMP), or do you require the original destination data to be placed in the background buffer (H5T_BKG_YES)? It should be possible to preserve only the temporary buffer facility (H5T_BKG_TEMP) while gaining most of the benefit of removing the background buffer, if people are currently using the background buffer as a temporary buffer.
Hi Neil,
I use H5T_BKG_TEMP as part of several conversion paths in *h5labview;*
specifically
in conversion paths where the object size changes - such as converting
between native (LabVIEW's "handle" based memory) and fixed length strings.
I would be keen to not have to rewrite that functionality as it's fairly
involved and has been running without error for some considerable time.
In order to simplify the HDF5 library code and allow us to implement
user-defined vlen conversions, we are considering removing the background
buffer from type conversion functions. This would cause the library to
issue an error if the need_bkg field in H5T_cdata_t were set to anything
other than H5T_BKG_NO, always pass NULL for the bkg argument to type
conversion functions, and ignore the bkg parameter for H5Pset_buffer. 1.10
may see these types and functions versioned with the aforementioned
arguments removed from the new versions.
Would anyone would be affected by removing the background buffer? If so,
are you supplying your own buffer to H5Pset_buffer, using the background
buffer as a temporary buffer in a type conversion function (H5T_BKG_TEMP),
or do you require the original destination data to be placed in the
background buffer (H5T_BKG_YES)? It should be possible to preserve only the
temporary buffer facility (H5T_BKG_TEMP) while gaining most of the benefit
of removing the background buffer, if people are currently using the
background buffer as a temporary buffer.
Thanks,
Neil Fortner
The HDF Group
_______________________________________________
Hdf-forum is for HDF software users discussion. Hdf-forum@lists.hdfgroup.org
Sorry, I'm late to the party. I use H5T_BKG_YES in Live HDF5 (also an interface to LabVIEW). IIRC, H5T_BKG_YES allows me to use re-use existing LabVIEW memory handles when reading from HDF5 datasets into memory that has already been allocated in LabVIEW. Without it, I would need to reallocate handles and may also leak LabVIEW memory.
Jason
···
On 1/20/2015 6:04 PM, Martijn Jasperse wrote:
Hi Neil,
I use H5T_BKG_TEMP as part of several conversion paths in /h5labview;/ specifically in conversion paths where the object size changes - such as converting between native (LabVIEW's "handle" based memory) and fixed length strings. I would be keen to not have to rewrite that functionality as it's fairly involved and has been running without error for some considerable time.
In order to simplify the HDF5 library code and allow us to
implement user-defined vlen conversions, we are considering
removing the background buffer from type conversion functions.
This would cause the library to issue an error if the need_bkg
field in H5T_cdata_t were set to anything other than H5T_BKG_NO,
always pass NULL for the bkg argument to type conversion
functions, and ignore the bkg parameter for H5Pset_buffer. 1.10
may see these types and functions versioned with the
aforementioned arguments removed from the new versions.
Would anyone would be affected by removing the background buffer?
If so, are you supplying your own buffer to H5Pset_buffer, using
the background buffer as a temporary buffer in a type conversion
function (H5T_BKG_TEMP), or do you require the original
destination data to be placed in the background buffer
(H5T_BKG_YES)? It should be possible to preserve only the
temporary buffer facility (H5T_BKG_TEMP) while gaining most of the
benefit of removing the background buffer, if people are currently
using the background buffer as a temporary buffer.
