I/O filter callback: "set_local" for read path?

Hi, folks

I’ve been asked by a few people about how to let HDF5-UDF take into account hyperslab selections made by the application. Unfortunately that’s not currently possible because HDF5-UDF is built upon the I/O filter interface, and the read callback does not include a handle for the dataspace – so there’s no way to retrieve that selection from the user-defined function.

I’m working on a fix for that, and I’d like to know which approach looks more appropriate for you:

  1. to add a new flag to set_local so that the function can check for H5Z_FLAG_REVERSE just like the filter callback does
  2. to create a new function prepare_read_data (or similar) that’s called exclusively by the read path
  3. none of the above :slight_smile: