re: https://github.com/Unidata/netcdf-c/issues/972
The current szip plugin code in the HDF5 library has some
unexpected behaviors that require some changes to how
nc_inq_var_szip is implemented and to the corresponding tests:
nc_test4/{test_szip,tst_vars3}.
Specifically, the following can happen:
1. The number of parameters provided by the user will be two,
but the number of parameters returned by nc_inq_var_filter
will be four because the HDF5 code (H5Zszip) will add two
extra parameters for internal use. It turns out that the two
parameters provided when calling nc_def_var_filter correspond
to the first two parameters of the four parameters returned
by nc_inq_var_filter.
2. The nc_inq_var_szip values corresponding to the ones provided
by the caller may be different than those provided by
nc_def_var_filter. The value of the options_mask argument is
known to add additional flag bits, and the pixels_per_block
parameter may be modified.
The in-memory files can be made persistent if nc_create is called with
NC_DISKLESS|NC_WRITE flags set. Initial test case also included.
- Modified ncio mechanism to support
multiple ncio packages; this is so we
can have posixio and memio operating
at the same time.
- cleanup up a bunch of lint issues (unused variables, etc).
