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NetCDF 3.5.0 Release Notes

Release 3.5.0 is mostly bug fixes and portability enhancements to version 3.4, but also includes Robert Pincus's Fortran90 interface. The netCDF file format is still unchanged, so files written with previous versions can be read or written with version 3.5.0.

There is a change in behavior: In netCDF 3.4, calling nc_close() or nc_endef() would remove any extra space in the header, causing all the data values to be moved up (towards the beginning of the file) if the space needed for the file header had decreased due to deleting an attribute or decreasing the number of attribute values. This was not the intended behavior and could be very costly for large datasets. In this version, extra space in the header persists and the size of the header will never shrink as the result of netCDF function calls. Hence space "reserved" by calling the nc__endef() function (or its equivalent in other language interfaces) will be preserved for later efficient additions of new attributes or non-record variables.

Changes

• Added Fortran 90 interface, which greatly simplifies the Fortran 77 interface, while improving compile-time checking. A User's Guide for the Fortran 90 interface is available in several forms.
• Changed C macro TIMELEN in file cxx/nctst.cpp to TIMESTRINGLEN to avoid clash with macro defined on AIX systems in /usr/include/time.h.
• Fixed miswriting of netCDF header when exiting define mode. Because the header was always written correctly later, this was only a problem if there was another reader of the netCDF file.
• Fixed explicit synchronizing between netCDF writer and readers via the nc_sync(), nf_sync(), and ncsync() functions.
• Fixed a number of bugs related to attempts to support shrinking the header in netCDF files when attributes are rewritten or deleted. Also fixed the problem that nc__endef() did not work as intended in reserving extra space in the file header, since the extra space would be compacted again on calling nc_close().
• Fixed the "redef bug" that occurred when nc_enddef() or nf_enddef() is called after nc_redef() or nf_redef(), the file is growing such that the new beginning of a record variable is in the next "chunk", and the size of at least one record variable exceeds the chunk size (see netcdf.3 man page for a description of this tuning parameter and how to set it). This bug resulted in corruption of some values in other variables than the one being added.
• The "__" tuning functions for the Fortran interface, nf__create, nf__open, and nf__enddef, are now documented in the Fortran interface man pages.
• Add an 'uninstall' target to all the Makefiles, thanks to Dave Glowacki.
• Added support provided by NERSC for multiprocessing on Cray T3E. Also includes changes to ffio option specification. The following functions are added to the public interface:

              nc__create_mp()
              nc__open_mp()
              nc_set_base_pe()
              nc_inq_base_pe()
  

• Fixed makefile URL for Win32 systems in INSTALL file.
• Made test for UNICOS system in the configure script case independent.
• Ported to additional systems and platforms.
• Changed the extension of C++ files from ".cc" to ".cpp". Renamed the C++ interface header file "netcdfcpp.h" instead of "netcdf.hh", changing "netcdf.hh" to include "netcdfcpp.h" for backward compatibility.
• Treat "FreeBSD" systems the same as "BSD/OS" system w.r.t. Fortran and "whatis" database.
• Corrected manual pages: corrected spelling of "enddef" (was "endef") and ensured that the words "index" and "format" will be correctly printed, instead of being expanded by m4.
• Updated support for Fortran-calling-C interface by updating "fortran/cfortran.h" from version 3.9 to version 4.1. This new version supports the Portland Group Fortran compiler (C macro "pgiFortran") and the Absoft Pro Fortran compiler (C macro "AbsoftProFortran").
• Corrected use of non-integral-constant-expression in specifying size of temporary arrays in file "libsrc/ncx_cray.c".
• Added Compaq Alpha Linux workstation example to INSTALL file.
• Ported cfortran.h to Cygnus GNU Win32 C compiler (gcc for Windows).
• Fixed bug in ncdump using same CDL header name when called with multiple files.
• Added new NULL data type NC_NAT (Not A Type) to facilitate checking whether a variable object has had its type defined yet, for example when working with packed values.
• Fixed use of compile-time macro NO_NETCDF_2 so it really doesn't include old netCDF-2 interfaces, as intended.
• Fixed C++ friend declarations to conform to C++ standard.
• Changed INSTALL file to INSTALL.html instead. Simplified and rewrote descriptions of installation.

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