Example 8. Operations on Field and Vdata Attributes

This example illustrates the use of VSsetattr/vsfscat/vsfsnat to attach
an attribute to a vdata and to a field in a vdata, the use of VSattrinfo/vsfainf
to get information about a field attribute and a vdata attribute, and the
use of VSgetattr/vsfgcat/vsfgnat to get the values of an attribute of a vdata
and the values of an attribute of a field in a vdata.  The example also shows
the use of VSfnattrs/vsffnas to obtain the number of attributes attached to a
field of a vdata and the use of VSnattrs/vsfnats to obtain the total number of
attributes attached to both a vdata and its fields.

In this example, the program finds the vdata, named "Solid Particle",
in the HDF file "General_Vdatas.hdf" produced by Example 3.  It then
obtains the index of the field, named "Mass", in the vdata.  An
attribute named "Site Ident" is attached to the vdata to contain the
identification of the experiment sites.  Another attribute named
"Scales" is attached to the field for its scale values.  The vdata
attribute has 3 character values and the field attribute has 4 integer
values.  

