disengagement of enable-netcdf4 from enable-hdf5.
That is, with the advent of nczarr, it is possible
to turn off hdf5 but still need netcdf-4 enabled
because nczarr uses libsrc4, but not libhdf5.
This change involves a bunch of things:
1. Modify configure.ac and CMakelist to make enable_hdf5
control if hdf5 support is provided. For back compatibility,
disable-netcdf4 is treated as disable-hdf5. But internally,
netcdf4 support is controlled only by the enabling of formats
that require it.
2. In support of #1, modify .travis.yml to use enable/disable-hdf5
instead of enable/disable-netcdf4.
3. test_common.in is modified to track selected features,
including enable-hdf5 and enable-s3-tests. This is used in
selected tests that mix netcdf-3 and netcdf4 tests.
4. The conflation of USE_HDF5 and USE_NETCDF4 is common in
code, tests, and build files, so all of those had to be weeded out.
5. It turns out that some of the NC4_dim functions really are HDF5 specific,
but are not treated as such. So they are moved from nc4dim.c to
hdf5dim.c or hdf5dispatch.c
6. Some generic functions in libhdf5 can be (and were) moved to libsrc4.
Primary fixes to get -ansi to work.
1. Convert all '//' C++ style comments to /*...*/ or to use #if 0...#endif
2. It turns out that when -ansi is specified, then a number of
functions no longer are defined in the header -- but they are still
in the .so file.<br>
The big example is strdup(). So, added code to include/ncconfig.h to define
externs for those missing functions that occur in more than one place.
These are enabled if !_WIN32 && __STDC__ == 1 (__STDC__ is supposed to
be the equivalent compile time flag to -ansi). Note that this requires
config.h (which references ncconfig.h) to be included in files where it is
currently not included. Single uses will be only in the file that uses them.
3. Added mmap test for the MAP_ANONYMOUS flag to configure.ac. Apparently
this is not always defined with -ansi.
4. fix some large integer constants in nc_test4/tst_atts3.c and nc_test4/tst_filterparser.c
to avoid compiler complaints.
5. fix a double constant in nc_test4/tst_filterparser.c to avoid compiler complaints.
[Note I suspect #4 and #5 will be a problem on big-endian machines, but we have no way to test]
Misc. Changes:
1. convert more instances of _MSC_VER to _WIN32.
2. added some debugging code to include/nctestserver.h
3. added comment about libdispatch/drc.c always being compiled.
4. modify parser generation in ncgen to remove unneeded files.
and https://github.com/Unidata/netcdf-c/issues/708
Expand the NC_INMEMORY capabilities to support writing and accessing
the final modified memory.
Three new functions have been added:
nc_open_memio, nc_create_mem, and nc_close_memio.
The following new capabilities were added.
1. nc_open_memio() allows the NC_WRITE mode flag
so a chunk of memory can be passed in and be modified
2. nc_create_mem() allows the NC_INMEMORY flag to be set
to cause the created file to be kept in memory.
3. nc_close_mem() allows the final in-memory contents to be
retrieved at the time the file is closed.
4. A special flag, NC_MEMIO_LOCK, is provided to ensure that
the provided memory will not be freed or reallocated.
Note the following.
1. If nc_open_memio() is called with NC_WRITE, and NC_MEMIO_LOCK is not set,
then the netcdf-c library will take control of the incoming memory.
This means that the original memory block should not be freed
but the block returned by nc_close_mem() must be freed.
2. If nc_open_memio() is called with NC_WRITE, and NC_MEMIO_LOCK is set,
then modifications to the original memory may fail if the space available
is insufficient.
Documentation is provided in the file docs/inmemory.md.
A test case is provided: nc_test/tst_inmemory.c driven by
nc_test/run_inmemory.sh
WARNING: changes were made to the dispatch table for
the close entry. From int (*close)(int) to int (*close)(int,void*).
