NAPI Example

[Chris Moreton-Smith]

Over the last two or three days I've had a fairly interesting time explaining 
what is going on to someone who is trying to construct their first NeXus file. 
 I think there are a few points which should be made here.

The example rather focuses on the NXdata vgroup at the expense of the others, 
unfortunately this seems to have had a rather misleading effect on the 
interpretation of how the standard works.  Here are a few of the confusions 
that have come up.

1) As the NXdata vgroup is almost unique in its use of attributes.  The first 
conclusion drawn is that all the dictionary entries are added as attributes to 
the respective groups - oops.

2) NXEntry gets missed out almost altogether (not helped by the fact that 
Nxclose is only called once in the example and not twice to return to the top 
level before closing the file!). The absence of other Vgroups and single valued 
entries in Nxentry rather helps with this.

3) MakeDATA gets associated with NXDATA  and not with any other item (quite 
naturally !).

Has anyone else found these interpretation problems?  If so could we improve or 
extend the examples to make the usage a bit clearer.  Any volunteers?

	Chris

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