[NeXus-tech] external linking in 4.3 API for python, swig, c++, fortran?

[Tobias.Richter at diamond.ac.uk]

The linking to external resources has improved in 4.3. We have now proper support for linking to groups and datasets. While conceptually there is no difference between the two the API used to allow only groups. To maintain most backward compatibility I've had to create a set of new functions to deal with datasets:

extern  NXstatus  NXisexternaldataset(NXhandle handle, CONSTCHAR *name, char *url, int urlLen);
extern  NXstatus  NXlinkexternaldataset(NXhandle handle, CONSTCHAR *name, CONSTCHAR *url);

They work in C and Java. If you feel NeXus 4.3 needs support for that in python, swig, c++ and/or fortran please let us know or better do the work.

I've changed the API for NXlinkexternal that creates a group link so that it does NOT work if the group already exists. Previously you had to create it beforehand. This has multiple disadvantages (you can overlay an existing group and such make the exiting information invisible for example), is not intuitive (ln -s target link works without preparation) and fails when the backend (hdf5) has the concept of a native link.

Otherwise this is not really related to the native HDF5 linking which is done under the hood by napi5.c with the help of napi.c and should just work (tm) for any binding.

Regards,

Tobias

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