@WardF WardF released this Mar 20, 2018 · 747 commits to master since this release

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We are happy to announce the availability of netCDF-C 4.6.1. This is primarily a maintenance release. In addition to numerous internal changes, cleanup, bug fixes and reorganization, some notable changes since netCDF-C 4.6.0 are as follows:

  • [Enhancement] Reverted some new behaviors that, while in line with the netCDF specification, broke existing workflows. See Github #843 for more information.
  • [Bug Fix] Corrected an issue which could result in a dap4 failure. See Github #888 for more information.
  • [Bug Fix][Enhancement] Allow nccopy to control output filter suppresion. See Github #894 for more information.
  • [Bug Fix] Improved support for CRT builds with Visual Studio, improves zlib detection in hdf5 library. See Github #853 for more information.
  • [Enhancement][Internal] Moved HDF4 into a distinct dispatch layer. See Github #849 for more information.

@WardF WardF released this Jan 25, 2018 · 945 commits to master since this release

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We are pleased to announce the netCDF-C 4.6.0 release. Highlighted changes from the 4.5.0 release are as follows:

  • [Enhancement] Full support for using HDF5 dynamic filters, both for reading and writing. See the file docs/filters.md.
  • [Enhancement] Reversed a handful of 4.5.0 changes which enforced documented-yet-previously-unenforced specifications, as these broke long established workflows.
  • [Enhancement] Added an option to enable strict null-byte padding for headers; this padding was specified in the spec but was not enforced. Enabling this option will allow you to check your files, as it will return an E_NULLPAD error. It is possible for these files to have been written by older versions of libnetcdf. There is no effective problem caused by this lack of null padding, so enabling these options is informational only. The options for configure and cmake are --enable-strict-null-byte-header-padding and -DENABLE_STRICT_NULL_BYTE_HEADER_PADDING, respectively. See Github #657 for more information.
  • [Enhancement] Reverted behavior/handling of out-of-range attribute values to pre-4.5.0 default. See Github #512 for more information.
  • [Bug] Fixed error in tst_parallel2.c. See Github #545 for more information.
  • [Bug] Fixed handling of corrupt files + proper offset handling for hdf5 files. See Github #552 for more information.
  • [Bug] Corrected a memory overflow in tst_h_dimscales, see Github #511, Github #505, Github #363 and Github #244 for more information.

@WardF WardF released this Oct 20, 2017 · 1497 commits to master since this release

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We are very happy to announce netCDF 4.5.0. In addition to general bug fixes and improvements, the improvements from the previous release candidate are listed below. For a full list of changes since the 4.4.1.1 release, please see the full Release Notes.


  • Corrected an issue which could potential result in a hang while using parallel file I/O. See Github #449 for more information.
  • Addressed an issue with ncdump not properly handling dates on a 366 day calendar. See GitHub #359 for more information.

@WardF WardF released this Sep 29, 2017 · 1530 commits to master since this release

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We are pleased to announce the third release candidate for netCDF 4.5.0. Assuming no further bug reports (won't that be nice!) we should have the full release out soon. In addition to general bug fixes, the main improvements from rc2 are as follows:


  • [Update] Due to ongoing issues, native CDF5 support has been disabled by default. You can use the options mentioned below (--enable-cdf5 or -DENABLE_CDF5=TRUE for configure or cmake, respectively). Just be aware that for the time being, Reading/Writing CDF5 files on 32-bit platforms may result in unexpected behavior when using extremely large variables. For 32-bit platforms it is best to continue using NC_FORMAT_64BIT_OFFSET.
  • [Bug] Corrected an issue where older versions of curl might fail. See GitHub #487 for more information.
  • [Enhancement] Added options to enable/disable CDF5 support at configure time for autotools and cmake-based builds. The options are --enable/disable-cdf5 and ENABLE_CDF5, respectively. See Github #484 for more information.
  • [Bug Fix] Corrected an issue when subsetting a netcdf3 file via nccopy -v/-V. See Github #425 and Github #463 for more information.
  • [Bug Fix] Corrected --has-dap and --has-dap4 output for cmake-based builds. See GitHub #473 for more information.
  • [Bug Fix] Corrected an issue where NC_64BIT_DATA files were being read incorrectly by ncdump, despite the data having been written correctly. See GitHub #457 for more information.
  • [Bug Fix] Corrected a potential stack buffer overflow. See GitHub #450 for more information.

Release Tarball - https://github.com/Unidata/netcdf-c/releases
Windows Installer Downloads - http://www.unidata.ucar.edu/software/netcdf/docs_rc/winbin.html
Documentation - http://www.unidata.ucar.edu/software/netcdf/docs_rc

@WardF WardF released this Aug 7, 2017 · 1648 commits to master since this release

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We are pleased to announce the second release candidate for netCDF 4.5.0. Assuming no further bug reports (won't that be nice!) we should have the full release out soon. In addition to general bug fixes, the main improvements from rc1 are as follows:

  • [Bug Fix] Addressed an issue with how cmake was implementing large file support on 32-bit systems. See GitHub #385 for more information.
  • [Bug Fix] Addressed an issue where ncgen would not respect keyword case. See GitHub #310 for more information.

The documentation and release code may be downloaded via the following links. We look forward to any feedback and suggestions. Once the official 4.5.0 release is out, we will move forward with the next versions of the Fortran and C++ interfaces.

@WardF WardF released this Jun 5, 2017 · 1726 commits to master since this release

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The following list captures the main changes/improvements/bug fixes since version 4.4.1.1:

4.5.0-rc1 - June 5, 2017

  • [Enhancement] DAP4 is now included. Since dap2 is the default for urls, dap4 must be specified by
    (1) using "dap4:" as the url protocol, or
    (2) appending "#protocol=dap4" to the end of the url, or
    (3) appending "#dap4" to the end of the url
    Note that dap4 is enabled by default but remote-testing is
    disbled until the testserver situation is resolved.
  • [Enhancement] The remote testing server can now be specified with the --with-testserver option to ./configure.
  • [Enhancement] Modified netCDF4 to use ASCII for NC_CHAR. See Github Pull request #316 for more information.
  • [Bug Fix] Corrected an error with how dimsizes might be read. See Github #410 for more information.
  • [Bug Fix] Corrected an issue where 'make check' would fail if 'make' or 'make all' had not run first. See Github #339 for more information.
  • [Bug Fix] Corrected an issue on Windows with Large file tests. See Github #385 for more information.
  • [Bug Fix] Corrected an issue with diskless file access, see Pull Request #400 and Pull Request #403 for more information.
  • [Upgrade] The bash based test scripts have been upgraded to use a common test_common.sh include file that isolates build specific information.
  • [Upgrade] The bash based test scripts have been upgraded to use a common test_common.sh include file that isolates build specific information.
  • [Refactor] the oc2 library is no longer independent of the main netcdf-c library. For example, it now uses ncuri, nclist, and ncbytes instead of its homegrown equivalents.
  • [Bug Fix] NC_EGLOBAL is now properly returned when attempting to set a global _FillValue attribute. See GitHub #388 and GitHub #389 for more information.
  • [Bug Fix] Corrected an issue where data loss would occur when _FillValue was mistakenly allowed to be redefined. See Github #390, GitHub #387 for more information.
  • [Upgrade][Bug] Corrected an issue regarding how "orphaned" DAS attributes were handled. See GitHub #376 for more information.
  • [Upgrade] Update utf8proc.[ch] to use the version now maintained by the Julia Language project (https://github.com/JuliaLang/utf8proc/blob/master/LICENSE.md).
  • [Bug] Addressed conversion problem with Windows sscanf. This primarily affected some OPeNDAP URLs on Windows. See GitHub #365 and GitHub #366 for more information.
  • [Enhancement] Added support for HDF5 collective metadata operations when available. Patch submitted by Greg Sjaardema, see Pull request #335 for more information.
  • [Bug] Addressed a potential type punning issue. See GitHub #351 for more information.
  • [Bug] Addressed an issue where netCDF wouldn't build on Windows systems using MSVC 2012. See GitHub #304 for more information.
  • [Bug] Fixed an issue related to potential type punning, see GitHub #344 for more information.
  • [Enhancement] Incorporated an enhancement provided by Greg Sjaardema, which may improve read/write times for some complex files. Basically, linked lists were replaced in some locations where it was safe to use an array/table. See Pull request #328 for more information.
Dec 25, 2016
ckp for writedata tag

@WardF WardF released this Nov 21, 2016 · 2039 commits to master since this release

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This is the official release of netCDF-C 4.4.1.1. This is a maintenance release which contains several important bug fixes. The Unidata/netCDF team recommend migrating to netCDF 4.4.1.1 as soon as is possible to avoid a potential, albeit rare, data loss issue in ncgen (as described below or detailed at #323).

Changes from version 4.4.1

Below is a list of notable changes from the previous release.

  • [Bug] Fixed an issue where ncgen would potentially crash or write incorrect netCDF4 binary data under very specific circumstances. This bug did not affect data written on 32-bit systems or by using the netCDF library; it was specific to ncgen. This would only happen when writing a compound data type containing an 8-byte data type followed by a 4-byte data type and the 4-byte data type was not properly aligned; this would possibly result in incorrect padding. This did not affect 32-bit systems, or data written directly by the library. See GitHub #323 for more information.
  • [Documentation] Updated documentation related to netCDF variable names and DAP2 access to reflect the undefined behavior potentially observed when DAP2 reserved keywords are used as netCDF variable names. See GitHub #308 for more information.
  • [Bug] Fixed an issue with nc_inq_type() not returning proper value in some circumstances. See GitHub #317 for more information.
  • [Bug] Corrected an issue related to test failures when --disable-utilities or -DENABLE_UTILITIES=OFF are specified when building with autotools or cmake, respectively. See GitHub #313 for more information.
  • [Bug][Enhancement] Corrected a behavioral issue with the _NCProperties attribute taking up too much space. See GitHub #300 and GitHub #301 for more information.
  • [Bug] Corrected behavior for nc-config so that, if nf-config is found in system, the proper fortran-related information will be conveyed. See [GitHub #296](https://github.com/Unidata/netcdf-c/issues/296] for more information.

@WardF WardF released this Jun 28, 2016 · 2192 commits to master since this release

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This is the official release of netCDF-C 4.4.1.

This release provides compatibility with libhdf5 1.10.0+; previous versions of netCDF will generate binary files which cannot be read on systems using older versions of libhdf5. A summary of changes between this official release and the previous release candidate are as follows:

  • [File Change] Starting with release 4.4.1, netCDF-4 files created will have superblock version 0 instead of superblock version 2, as was observed in previous netCDF versions. This is due to a workaround required to avoid backwards binary incompatibility when using libhdf5 1.10.x or greater. Superblock versions 0 and 2 appear to be forward and backward compatible. Other than a different superblock number the data should remain consistent.
  • [Enhancement] Added better error reporting when ncdump/nccopy are given a bad constraint in a DAP url. See GitHub #279 for more information.

Full release notes are available here.

Pre-release

@WardF WardF released this Jun 20, 2016 · 2206 commits to master since this release

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This is the third release candidate for netCDF-C 4.4.1. It contains various improvements and bug fixes over the previous release candidate. The notes for this release may be seen below, and the full list of release notes may be seen here. Notable improvements are as follows:

4.4.1-RC3 - June 17, 2016

  • [Bug Fix] Corrected an issue where adding a _FillValue attribute to a variable would result in other attributes being lost. See GitHub #239 for more details.
  • [Bug Fix][Parallel I/O] Corrected an issue reported by Kent Yang at the HDF group related to Collective Parallel I/O and a potential hang.
  • [Bug Fix] Misc. bug fixes and improvements.