Unidata

NetCDF 4.1.2 Release Notes

The Unidata NetCDF group is pleased to announce the new 4.1.2 release of the netCDF C/Fortran libraries. This release contains bug fixes and internal refactoring.

Users of parallel I/O with netCDF-4 please note: starting with the 4.1.2 release the parallel I/O functions are prototyped in netcdf_par.h, not netcdf.h. You must include netcdf_par.h BEFORE netcdf.h to use parallel I/O with netCDF-4.

• Rewrite netCDF-4 attribute put code for a large speedup when writing lots of attributes.
• Fix nc-config --libs when static dependent libraries are not installed in the same directory as netCDF libraries (thanks to Jeff Whitaker).
• Build shared libraries by default, requiring separate Fortran library. Static libraries now built only with --disable-shared.
• Refactor of HDF5 file metadata scan for large speedup in opening files, especially large files.
• Complete rewrite of the handling of character datalist constants. The heuristics are documented in ncgen.1.
• Eliminate use of NC_MAX_DIMS and NC_MAX_VARS in ncdump and nccopy, allocating memory as needed and reducing their memory footprint.
• Add documentation for new nc_inq_path() function.
• Use hashing to speedup lookups by name for files with lots of dimensions and variables (thanks to Greg Sjaardema).
• Add options to nccopy to support uniform compression of variables in output, shuffling, and fixing unlimited dimensions. Add option to support specifying chunking in output in terms of dimension names.
• Modified opendap constraint parser to be more compatible with a java version of the parser.
• Modified ncgen to utilize iterators internally; should be no user visible effect.
• An internal refactoring of the C library allows for easier maintainance and extension of the netCDF library. This restructuring of the library code is invisible to the end-user. Two new directories have been added to the netCDF build: libdispatch, which decides whether to call a netcdf classic, netcdf-4, or opendap version of each function in the API, and liblib, where, depending on the configure choices, the final netCDF library is assembled from convenience libraries created in other directories.
• Fix for make bug which caused documentation to be unnecessarily rebuilt after make clean.
• Fix for bug in accessing a multidimensional variable with more than 4 billion values on a 32-bit platform.
• Fix for memory performance problems in parallel I/O. The automatic use of HDF5 buffers in parallel programs with netCDF-4 resulted in large memory use.
• Fix netCDF-4 bug caused when doing enddef/redef and then defining coordinate variable out of order.
• Refactoring of netCDF-4 internals to reduce memory use and end dependence on size of NC_MAX_DIMS and NC_MAX_NAME.
• Fix "ncdump -c" bug identifying coordinate variables in groups.
• Fix bug in libsrc/posixio.c when providing sizehint larger than default, which then doesn't get used (thanks to Harald Anlauf).
• The netCDF C/Fortran/C++ source code has been moved to Unidata's subversion server. Interested users can now examine the netCDF code in its full glory and gory internals at http://svn.unidata.ucar.edu/netcdf.
• Documentation improvements, especially relating to creating netCDF-4 compatible files with HDF5 only.

The 4.1.2 release source code is available from the following URL. ftp://ftp.unidata.ucar.edu/pub/netcdf/netcdf-4.1.2.tar.gz or ftp://ftp.unidata.ucar.edu/pub/netcdf/netcdf-4.1.2.tar.Z

Build it according to these instructions: http://www.unidata.ucar.edu/software/netcdf/docs/netcdf-install.html#Quick-Instructions

Report problems to the support email address:

support-netcdf@unidata.ucar.edu