I think that I have deeper understanding of DLLCC now and published a new patch using double dispatching on the public store. This enables passing a Smallapack.CArrayAccessor as argument to the external function call. What's this thing (the name is not so nice)? It's a proxy to some C data (on heap), somehow like a CPointer (a CType plus a pointer on C data), but with two differences:
- it carries a length, and thus enables safe access of contents from within the Smalltalk world. If you think of it two minutes, every pointer should be bounded, that's clearly the way to go. Alas, in 2018 we still are at assembler level with those C API, so the pointer coming from external world still are unbounded (a pity for safety...).
- it is using 1-based index and enables handling from within Smalltalk world like any other collection without too much mindstorm.
Along with the CArrayAccessor change, I can now explore the contents of a HDF5 file created by Matlab save -v7.3. a Small step in the right direction.