Update History-1_12.txt and RELEASE.txt after release of HDF5 1.12.1.

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+++ b/release_docs/HISTORY-1_12.txt
@@ -3,10 +3,1311 @@ HDF5 History
 
 This file contains development history of the HDF5 1.12 branch
 
+02.      Release Information for hdf5-1.12.1
 01.      Release Information for hdf5-1.12.0
 
 [Search on the string '%%%%' for section breaks of each release.]
 
+%%%%1.12.1%%%%
+
+HDF5 version 1.12.1 released on 2021-07-01
+================================================================================
+
+
+INTRODUCTION
+============
+
+This document describes the new features introduced in the HDF5 1.12.1 release.
+It contains information on the platforms tested and known problems in this
+release. For more details check the HISTORY*.txt files in the HDF5 source.
+
+Note that documentation in the links below will be updated at the time of the
+release.
+
+Links to HDF5 documentation can be found on The HDF5 web page:
+
+     https://portal.hdfgroup.org/display/HDF5/HDF5
+
+The official HDF5 releases can be obtained from:
+
+     https://www.hdfgroup.org/downloads/hdf5/
+
+More information about the new features can be found at:
+
+     https://portal.hdfgroup.org/display/HDF5/New+Features+in+HDF5+Release+1.12
+
+If you have any questions or comments, please send them to the HDF Help Desk:
+
+     help@hdfgroup.org
+
+
+CONTENTS
+========
+
+- New Features
+- Support for new platforms and languages
+- Bug Fixes since HDF5-1.12.0
+- Supported Platforms
+- Tested Configuration Features Summary
+- More Tested Platforms
+- Known Problems
+- CMake vs. Autotools installations
+
+
+New Features
+============
+
+    Configuration:
+    -------------
+   - Adds C++ Autotools configuration file for Intel
+
+      * Checks for icpc as the compiler
+      * Copies most non-warning flags from intel-flags
+
+      (DER - 2021/06/02)
+
+    - Adds C++ Autotools configuration file for PGI
+
+      * Checks for pgc++ as the compiler name (was: pgCC)
+      * Other options basically match new C options (below)
+
+      (DER - 2021/06/02)
+
+    - Updates PGI C options
+
+      * -Minform set to warn (was: inform) to suppress spurious messages
+      * Sets -gopt -O2 as debug options
+      * Sets -O4 as 'high optimization' option
+      * Sets -O0 as 'no optimization' option
+      * Removes specific settings for PGI 9 and 10
+
+      (DER - 2021/06/02)
+
+    - Added an option to make the global thread-safe lock a recursive R/W lock
+
+      Prior to this release, the HDF5 library supported multi-threaded
+      applications by placing a recursive global lock on the entire library,
+      thus allowing only one thread into the library at a time.
+
+      While this is still the default, the library can now be built with the
+      recursive global lock replaced with a recursive read / write (R/W) lock
+      that allows recursive writer locks.
+
+      Currently, this change results in no functional change in the HDF5
+      library, as all threads will have to acquire a write lock on entry, and
+      thus obtain exclusive access to the HDF5 library as before. However, the
+      addition of the recursive R/W lock is a prerequisite for further work
+      directed at allowing some subset of the HDF5 API calls to enter the
+      library with read locks.
+
+      CMake:      HDF5_USE_RECURSIVE_RW_LOCKS (default: OFF, advanced)
+
+      Autotools:  --enable-recursive-rw-locks [default=no]
+
+      This feature only works with Pthreads. Win32 threads are not supported.
+
+      (DER - 2021/05/10)
+
+    - CMake no longer builds the C++ library by default
+
+      HDF5_BUILD_CPP_LIB now defaults to OFF, which is in line with the
+      Autotools build defaults.
+
+      (DER - 2021/04/20)
+
+    - Removal of pre-VS2015 work-arounds
+
+      HDF5 now requires Visual Studio 2015 or greater, so old work-around
+      code and definitions have been removed, including:
+
+      * <inttypes.h>
+      * snprintf and vsnprintf
+      * llround, llroundf, lround, lroundf, round, roundf
+      * strtoll and strtoull
+      * va_copy
+      * struct timespec
+
+      (DER - 2021/03/22)
+
+    - Added CMake variable HDF5_LIB_INFIX
+
+      This infix is added to all library names after 'hdf5'.
+      e.g. the infix '_openmpi' results in the library name 'libhdf5_openmpi.so'
+      This name is used in packages on debian based systems.
+      (see https://packages.debian.org/jessie/amd64/libhdf5-openmpi-8/filelist)
+
+      (RG - 2021/03/22)
+
+    - On macOS, Universal Binaries can now be built, allowing native execution on
+      both Intel and Apple Silicon (ARM) based Macs.
+
+      To do so, set CMAKE_OSX_ARCHITECTURES="x86_64;arm64"
+
+      (SAM - 2021/02/07, github-311)
+
+    - Added a configure-time option to control certain compiler warnings
+      diagnostics
+
+      A new configure-time option was added that allows some compiler warnings
+      diagnostics to have the default operation. This is mainly intended for
+      library developers and currently only works for gcc 10 and above. The
+      diagnostics flags apply to C, C++ and Fortran compilers and will appear
+      in "H5 C Flags", H5 C++ Flags" and H5 Fortran Flags, respectively. They
+      will NOT be exported to h5cc, etc.
+
+      The default is OFF, which will disable the warnings URL and color attributes
+      for the warnings output. ON will not add the flags and allow default behavior.
+
+      Autotools:    --enable-diags
+
+      CMake:        HDF5_ENABLE_BUILD_DIAGS
+
+      (ADB - 2021/02/05, HDFFV-11213)
+
+    - CMake option to build the HDF filter plugins project as an external project
+
+      The HDF filter plugins project is a collection of registered compression
+      filters that can be dynamically loaded when needed to access data stored
+      in a hdf5 file. This CMake-only option allows the plugins to be built and
+      distributed with the hdf5 library and tools. Like the options for szip and
+      zlib, either a tgz file or a git repository can be specified for the source.
+
+      The option was refactored to use the CMake FetchContent process. This allows
+      more control over the filter targets, but required external project command
+      options to be moved to a CMake include file, HDF5PluginCache.cmake. Also
+      enabled the filter examples to be used as tests for operation of the
+      filter plugins.
+
+      (ADB - 2020/12/10, OESS-98)
+
+    - FreeBSD Autotools configuration now defaults to 'cc' and 'c++' compilers
+
+      On FreeBSD, the autotools defaulted to 'gcc' as the C compiler and did
+      not process C++ options. Since FreeBSD 10, the default compiler has
+      been clang (via 'cc').
+
+      The default compilers have been set to 'cc' for C and 'c++' for C++,
+      which will pick up clang and clang++ respectively on FreeBSD 10+.
+      Additionally, clang options are now set correctly for both C and C++
+      and g++ options will now be set if that compiler is being used (an
+      omission from the former functionality).
+
+      (DER - 2020/11/28, HDFFV-11193)
+
+    - Fixed POSIX problems when building w/ gcc on Solaris
+
+      When building on Solaris using gcc, the POSIX symbols were not
+      being set correctly, which could lead to issues like clock_gettime()
+      not being found.
+
+      The standard is now set to gnu99 when building with gcc on Solaris,
+      which allows POSIX things to be #defined and linked correctly. This
+      differs slightly from the gcc norm, where we set the standard to c99
+      and manually set POSIX #define symbols.
+
+      (DER - 2020/11/25, HDFFV-11191)
+
+    - Added a configure-time option to consider certain compiler warnings
+      as errors
+
+      A new configure-time option was added that converts some compiler warnings
+      to errors. This is mainly intended for library developers and currently
+      only works for gcc and clang. The warnings that are considered errors
+      will appear in the generated libhdf5.settings file. These warnings apply
+      to C and C++ code and will appear in "H5 C Flags" and H5 C++ Flags",
+      respectively. They will NOT be exported to h5cc, etc.
+
+      The default is OFF. Building with this option may fail when compiling
+      on operating systems and with compiler versions not commonly used by
+      the library developers. Compilation may also fail when headers not
+      under the control of the library developers (e.g., mpi.h, hdfs.h) raise
+      warnings.
+
+      Autotools:    --enable-warnings-as-errors
+
+      CMake:        HDF5_ENABLE_WARNINGS_AS_ERRORS
+
+      (DER - 2020/11/23, HDFFV-11189)
+
+    - Autotools and CMake target added to produce doxygen generated documentation
+
+      The default is OFF or disabled.
+      Autoconf option is '--enable-doxygen'
+          autotools make target is 'doxygen' and will build all doxygen targets
+          CMake configure option is 'HDF5_BUILD_DOC'.
+          CMake target is 'doxygen' for all available doxygen targets
+          CMake target is 'hdf5lib_doc' for the src subdirectory
+
+        (ADB - 2020/11/13, HDFFV-11243)
+
+    - CMake option to use MSVC naming conventions with MinGW
+
+      HDF5_MSVC_NAMING_CONVENTION option enables the use of MSVC naming
+      conventions when using a MinGW toolchain
+
+      (xan - 2020/10/30)
+
+    - CMake option to statically link gcc libs with MinGW
+
+      HDF5_MINGW_STATIC_GCC_LIBS allows to statically link libg/libstdc++
+      with the MinGW toolchain
+
+      (xan - 2020/10/30)
+
+    - CMake option to build the HDF filter plugins project as an external project
+
+      The HDF filter plugins project is a collection of registered compression
+      filters that can be dynamically loaded when needed to access data stored
+      in a hdf5 file. This CMake-only option allows the plugins to be built and
+      distributed with the hdf5 library and tools. Like the options for szip and
+      zlib, either a tgz file or a git repository can be specified for the source.
+
+      The necessary options are (see the INSTALL_CMake.txt file):
+          HDF5_ENABLE_PLUGIN_SUPPORT
+          PLUGIN_TGZ_NAME or PLUGIN_GIT_URL
+      There are more options necessary for various filters and the plugin project
+      documents should be referenced.
+
+      (ADB - 2020/10/16, OESS-98)
+    - Added CMake option to format source files
+
+      HDF5_ENABLE_FORMATTERS option will enable creation of targets using the
+      pattern - HDF5_*_SRC_FORMAT - where * corresponds to the source folder
+      or tool folder. All sources can be formatted by executing the format target;
+      make format
+
+      (ADB - 2020/09/24)
+
+    - Disable memory sanity checks in the Autotools in release branches
+
+      The library can be configured to use internal memory sanity checking,
+      which replaces C API calls like malloc(3) and free(3) with our own calls
+      which add things like heap canaries. These canaries can cause problems
+      when external filter plugins reallocate canary-marked buffers.
+
+      For this reason, the default will be to not use the memory allocation
+      sanity check feature in release branches (e.g., hdf5_1_10_7).
+      Debug builds in development branches (e.g., develop, hdf5_1_10) will
+      still use them by default.
+
+      This change only affects Autotools debug builds. Non-debug autotools
+      builds and all CMake builds do not enable this feature by default.
+
+      (DER - 2020/08/19)
+
+    - Add file locking configure and CMake options
+
+      HDF5 1.10.0 introduced a file locking scheme, primarily to help
+      enforce SWMR setup. Formerly, the only user-level control of the scheme
+      was via the HDF5_USE_FILE_LOCKING environment variable.
+
+      This change introduces configure-time options that control whether
+      or not file locking will be used and whether or not the library
+      ignores errors when locking has been disabled on the file system
+      (useful on some HPC Lustre installations).
+
+      In both the Autotools and CMake, the settings have the effect of changing
+      the default property list settings (see the H5Pset/get_file_locking()
+      entry, below).
+
+      The yes/no/best-effort file locking configure setting has also been
+      added to the libhdf5.settings file.
+
+      Autotools:
+
+        An --enable-file-locking=(yes|no|best-effort) option has been added.
+
+        yes:          Use file locking.
+        no:           Do not use file locking.
+        best-effort:  Use file locking and ignore "disabled" errors.
+
+      CMake:
+
+        Two self-explanatory options have been added:
+
+        HDF5_USE_FILE_LOCKING
+        HDF5_IGNORE_DISABLED_FILE_LOCKS
+
+        Setting both of these to ON is the equivalent to the Autotools'
+        best-effort setting.
+
+      NOTE:
+      The precedence order of the various file locking control mechanisms is:
+
+        1) HDF5_USE_FILE_LOCKING environment variable (highest)
+
+        2) H5Pset_file_locking()
+
+        3) configure/CMake options (which set the property list defaults)
+
+        4) library defaults (currently best-effort)
+
+      (DER - 2020/07/30, HDFFV-11092)
+
+    - CMake option to link the generated Fortran MOD files into the include
+      directory.
+
+      The Fortran generation of MOD files by a Fortran compile can produce
+      different binary files between SHARED and STATIC compiles with different
+      compilers and/or different platforms. Note that it has been found that
+      different versions of Fortran compilers will produce incompatible MOD
+      files. Currently, CMake will locate these MOD files in subfolders of
+      the include directory and add that path to the Fortran library target
+      in the CMake config file, which can be used by the CMake find library
+      process. For other build systems using the binary from a CMake install,
+      a new CMake configuration can be used to copy the pre-chosen version
+      of the Fortran MOD files into the install include directory.
+
+      The default will depend on the configuration of
+      BUILD_STATIC_LIBS and BUILD_SHARED_LIBS:
+            YES                   YES         Default to SHARED
+            YES                   NO          Default to STATIC
+            NO                    YES         Default to SHARED
+            NO                    NO          Default to SHARED
+      The defaults can be overridden by setting the config option
+            HDF5_INSTALL_MOD_FORTRAN to one of NO, SHARED, or STATIC
+
+      (ADB - 2020/07/09, HDFFV-11116)
+
+    - CMake option to use AEC (open source SZip) library instead of SZip
+
+      The open source AEC library is a replacement library for SZip. In
+      order to use it for hdf5 the libaec CMake source was changed to add
+      "-fPIC" and exclude test files. Autotools does not build the
+      compression libraries within hdf5 builds. New option USE_LIBAEC is
+      required to compensate for the different files produced by AEC build.
+
+      (ADB - 2020/04/22, OESS-65)
+
+    - CMake ConfigureChecks.cmake file now uses CHECK_STRUCT_HAS_MEMBER
+
+      Some handcrafted tests in HDFTests.c has been removed and the CMake
+      CHECK_STRUCT_HAS_MEMBER module has been used.
+
+      (ADB - 2020/03/24, TRILAB-24)
+
+    - Both build systems use same set of warnings flags
+
+      GNU C, C++ and gfortran warnings flags were moved to files in a config
+      sub-folder named gnu-warnings. Flags that only are available for a specific
+      version of the compiler are in files named with that version.
+      Clang C warnings flags were moved to files in a config sub-folder
+      named clang-warnings.
+      Intel C, Fortran warnings flags were moved to files in a config sub-folder
+      named intel-warnings.
+
+      There are flags in named "error-xxx" files with warnings that may
+      be promoted to errors. Some source files may still need fixes.
+
+      There are also pairs of files named "developer-xxx" and "no-developer-xxx"
+      that are chosen by the CMake option:HDF5_ENABLE_DEV_WARNINGS or the
+      configure option:--enable-developer-warnings.
+
+      In addition, CMake no longer applies these warnings for examples.
+
+      (2020/03/24, TRILAB-192)
+
+
+    Library:
+    --------
+    - H5Gcreate1() now rejects size_hint parameters larger than UINT32_MAX
+
+      The size_hint value is ultimately stored in a uint32_t struct field,
+      so specifying a value larger than this on a 64-bit machine can cause
+      undefined behavior including crashing the system.
+
+      The documentation for this API call was also incorrect, stating that
+      passing a negative value would cause the library to use a default
+      value. Instead, passing a "negative" value actually passes a very large
+      value, which is probably not what the user intends and can cause
+      crashes on 64-bit systems.
+
+      The Doxygen documentation has been updated and passing values larger
+      than UINT32_MAX for size_hint will now produce a normal HDF5 error.
+
+      (DER - 2021/04/29, HDFFV-11241)
+
+
+
+    - H5Pset_fapl_log() no longer crashes when passed an invalid fapl ID
+
+      When passed an invalid fapl ID, H5Pset_fapl_log() would usually
+      segfault when attempting to free an uninitialized pointer in the error
+      handling code. This behavior is more common in release builds or
+      when the memory sanitization checks were not selected as a build
+      option.
+
+      The pointer is now correctly initialized and the API call now
+      produces a normal HDF5 error when fed an invalid fapl ID.
+
+      (DER - 2021/04/28, HDFFV-11240)
+
+    - Fixes a segfault when H5Pset_mdc_log_options() is called multiple times
+
+      The call incorrectly attempts to free an internal copy of the previous
+      log location string, which causes a segfault. This only happens
+      when the call is invoked multiple times on the same property list.
+      On the first call to a given fapl, the log location is set to NULL so
+      the segfault does not occur.
+
+      The string is now handled properly and the segfault no longer occurs.
+
+      (DER - 2021/04/27, HDFFV-11239)
+
+    - HSYS_GOTO_ERROR now emits the results of GetLastError() on Windows
+
+      HSYS_GOTO_ERROR is an internal macro that is used to produce error
+      messages when system calls fail. These strings include errno and the
+      the associated strerror() value, which are not particularly useful
+      when a Win32 API call fails.
+
+      On Windows, this macro has been updated to include the result of
+      GetLastError(). When a system call fails on Windows, usually only
+      one of errno and GetLastError() will be useful, however we emit both
+      for the user to parse. The Windows error message is not emitted as
+      it would be awkward to free the FormatMessage() buffer given the
+      existing HDF5 error framework. Users will have to look up the error
+      codes in MSDN.
+
+      The format string on Windows has been changed from:
+
+          "%s, errno = %d, error message = '%s'"
+
+      to:
+
+          "%s, errno = %d, error message = '%s', Win32 GetLastError() = %"PRIu32""
+
+      for those inclined to parse it for error values.
+
+      (DER - 2021/03/21)
+
+    - File locking now works on Windows
+
+      Since version 1.10.0, the HDF5 library has used a file locking scheme
+      to help enforce one reader at a time accessing an HDF5 file, which can
+      be helpful when setting up readers and writers to use the single-
+      writer/multiple-readers (SWMR) access pattern.
+
+      In the past, this was only functional on POSIX systems where flock() or
+      fcntl() were present. Windows used a no-op stub that always succeeded.
+
+      HDF5 now uses LockFileEx() and UnlockFileEx() to lock the file using the
+      same scheme as POSIX systems. We lock the entire file when we set up the
+      locks (by passing DWORDMAX as both size parameters to LockFileEx()).
+
+      (DER - 2021/03/19, HDFFV-10191)
+
+    - H5Epush_ret() now requires a trailing semicolon
+
+      H5Epush_ret() is a function-like macro that has been changed to
+      contain a `do {} while(0)` loop. Consequently, a trailing semicolon
+      is now required to end the `while` statement. Previously, a trailing
+      semi would work, but was not mandatory. This change was made to allow
+      clang-format to correctly format the source code.
+
+      (SAM - 2021/03/03)
+
+    - Improved performance of H5Sget_select_elem_pointlist
+
+      Modified library to cache the point after the last block of points
+      retrieved by H5Sget_select_elem_pointlist, so a subsequent call to the
+      same function to retrieve the next block of points from the list can
+      proceed immediately without needing to iterate over the point list.
+
+      (NAF - 2021/01/19)
+
+    - Added H5VL_VERSION macro that indicates the version of the VOL framework
+      implemented by a version of the library.  Currently, compatibility
+      checking enforces that the 'version' field in the H5VL_class_t for
+      a VOL connector must match the version of the VOL framework for the
+      library when it is registered or dynamically loaded.
+
+      (QAK - 2020/12/10)
+
+    - Add BEST_EFFORT value to HDF5_USE_FILE_LOCKING environment variable
+
+      This change adds a BEST_EFFORT to the TRUE/FALSE, 1/0 settings that
+      were previously accepted. This option turns on file locking but
+      ignores locking errors when the library detects that file locking
+      has been disabled on a file system (useful on some HPC Lustre
+      installations).
+
+      The capitalization of BEST_EFFORT is mandatory.
+
+      See the configure option discussion for HDFFV-11092 (above) for more
+      information on the file locking feature and how it's controlled.
+
+      (DER - 2020/07/30, HDFFV-11092)
+
+
+    - Add H5Pset/get_file_locking() API calls
+
+      This change adds new API calls which can be used to set or get the
+      file locking parameters. The single API call sets both the "use file
+      locking" flag and the "ignore disabled file locking" flag.
+
+      When opening a file multiple times without closing, the file MUST be
+      opened with the same file locking settings. Opening a file with different
+      file locking settings will fail (this is similar to the behavior of
+      H5Pset_fclose_degree()).
+
+      See the configure option discussion for HDFFV-11092 (above) for more
+      information on the file locking feature and how it's controlled.
+
+      (DER - 2020/07/30, HDFFV-11092)
+
+    - Added two new API routines for tracking library memory use:
+      H5get_alloc_stats() and H5get_free_list_sizes().
+
+      (QAK - 2020/03/25)
+
+    - Add Mirror VFD
+
+      Use TCP/IP sockets to perform write-only (W/O) file I/O on a remote
+      machine. Must be used in conjunction with the Splitter VFD.
+
+      (JOS - 2020/03/13, TBD)
+
+    - Add Splitter VFD
+
+      Maintain separate R/W and W/O channels for "concurrent" file writes
+      to two files using a single HDF5 file handle.
+
+      (JOS - 2020/03/13, TBD)
+
+
+    C++ Library:
+    ------------
+    - Add wrappers for H5Pset/get_file_locking() API calls
+
+      FileAccPropList::setFileLocking()
+      FileAccPropList::getFileLocking()
+
+      See the configure option discussion for HDFFV-11092 (above) for more
+      information on the file locking feature and how it's controlled.
+
+      (DER - 2020/07/30, HDFFV-11092)
+
+    Java Library:
+    -------------
+    - Added new H5S functions.
+
+      H5Sselect_copy, H5Sselect_shape_same, H5Sselect_adjust,
+      H5Sselect_intersect_block, H5Sselect_project_intersection,
+      H5Scombine_hyperslab, H5Smodify_select, H5Scombine_select
+      wrapper functions added.
+
+      (ADB - 2020/10/27, HDFFV-10868)
+
+    - Add wrappers for H5Pset/get_file_locking() API calls
+
+      H5Pset_file_locking()
+      H5Pget_use_file_locking()
+      H5Pget_ignore_disabled_file_locking()
+
+      Unlike the C++ and Fortran wrappers, there are separate getters for the
+      two file locking settings, each of which returns a boolean value.
+
+      See the configure option discussion for HDFFV-11092 (above) for more
+      information on the file locking feature and how it's controlled.
+
+      (ADB - 2020/07/30, HDFFV-11092)
+
+
+    Tools:
+    ------
+    - h5repack added help text for user-defined filters.
+
+      Added help text line that states the valid values of the filter flag
+      for user-defined filters;
+          filter_flag: 1 is OPTIONAL or 0 is MANDATORY
+
+      (ADB - 2021/01/14, HDFFV-11099)
+
+    - h5repack added options to control how external links are handled.
+
+      Currently h5repack preserves external links and cannot copy and merge
+      data from the external files. Two options, merge and prune, were added to
+      control how to merge data from an external link into the resulting file.
+            --merge             Follow external soft link recursively and merge data.
+            --prune             Do not follow external soft links and remove link.
+            --merge --prune     Follow external link, merge data and remove dangling link.
+
+      (ADB - 2020/08/05, HDFFV-9984)
+
+
+Support for new platforms, languages and compilers
+==================================================
+
+    - Added macOS 11.2 Big Sur
+
+
+Bug Fixes since HDF5-1.12.0 release
+===================================
+
+    Library
+    -------
+    - Fixed CVE-2018-14460
+
+      The tool h5repack produced a segfault when the rank in dataspace
+      message was corrupted, causing invalid read while decoding the
+      dimension sizes.
+
+      The problem was fixed by ensuring that decoding the dimension sizes
+      and max values will not go beyong the end of the buffer.
+
+      (BMR - 2021/05/12, HDFFV-11223)
+
+    - Fixed CVE-2019-9151
+
+      h5repack generated a segfault when an invalid memory read occurred on
+      a corrupted file.
+
+      The issue is now fixed. h5repack produces an error instead of segfault.
+
+      (BMR - 2021/05/04, HDFFV-10718)
+
+    - Fixed CVE-2018-11206
+
+      The tool h5dump produced a segfault when the size of a fill value
+      message was corrupted and caused a buffer overflow.
+
+      The problem was fixed by verifying the fill value's size
+      against the buffer size before attempting to access the buffer.
+
+      (BMR - 2021/03/15, HDFFV-10480)
+
+    - Fixed CVE-2018-14033 (same issue as CVE-2020-10811)
+
+      The tool h5dump produced a segfault when the storage size message
+      was corrupted and caused a buffer overflow.
+
+      The problem was fixed by verifying the storage size against the
+      buffer size before attempting to access the buffer.
+
+      (BMR - 2021/03/15, HDFFV-11159/HDFFV-11049)
+
+    - Remove underscores on header file guards
+
+      Header file guards used a variety of underscores at the beginning of the define.
+
+      Removed all leading (some trailing) underscores from header file guards.
+
+      (ADB - 2021/03/03, #361)
+
+    - Fixed issue with MPI communicator and info object not being
+      copied into new FAPL retrieved from H5F_get_access_plist
+
+      Added logic to copy the MPI communicator and info object into
+      the output FAPL. MPI communicator is retrieved from the VFD, while
+      the MPI info object is retrieved from the file's original FAPL.
+
+      (JTH - 2021/02/15, HDFFV-11109)
+
+    - Fixed problems with vlens and refs inside compound using
+      H5VLget_file_type()
+
+      Modified library to properly ref count H5VL_object_t structs and only
+      consider file vlen and reference types to be equal if their files are
+      the same.
+
+      (NAF - 2021/01/22)
+
+    - Fix bug and simplify collective metadata write operation when some ranks
+      have no entries to contribute.  This fixes parallel regression test
+      failures with IBM SpectrumScale MPI on the Summit system at ORNL.
+
+      (QAK - 2020/09/02)
+
+    - Avoid setting up complex MPI types with 0-length vectors, which some
+      MPI implementations don't handle well.  (In particular, IBM
+      SpectrumScale MPI on the Summit system at ORNL)
+
+      (QAK - 2020/08/21)
+
+    - Fixed use-of-uninitialized-value error
+
+      Appropriate initialization of local structs was added to remove the
+      use-of-uninitialized-value errors reported by MemorySanitizer.
+
+      (BMR - 2020/8/13, HDFFV-11101)
+
+    - Creation of dataset with optional filter
+
+      When the combination of type, space, etc doesn't work for filter
+      and the filter is optional, it was supposed to be skipped but it was
+      not skipped and the creation failed.
+
+      A fix is applied to allow the creation of a dataset in such
+      situation, as specified in the user documentation.
+
+      (BMR - 2020/8/13, HDFFV-10933)
+
+    - Explicitly declared dlopen to use RTLD_LOCAL
+
+      dlopen documentation states that if neither RTLD_GLOBAL nor
+      RTLD_LOCAL are specified, then the default behavior is unspecified.
+      The default on linux is usually RTLD_LOCAL while macos will default
+      to RTLD_GLOBAL.
+
+      (ADB - 2020/08/12, HDFFV-11127)
+
+    - Fixed issues CVE-2018-13870 and CVE-2018-13869
+
+      When a buffer overflow occurred because a name length was corrupted
+      and became very large, h5dump crashed on memory access violation.
+
+      A check for reading past the end of the buffer was added to multiple
+      locations to prevent the crashes and h5dump now simply fails with an
+      error message when this error condition occurs.
+
+      (BMR - 2020/7/31, HDFFV-11120 and HDFFV-11121)
+
+    - H5Sset_extent_none() sets the dataspace class to H5S_NO_CLASS which
+      causes asserts/errors when passed to other dataspace API calls.
+
+      H5S_NO_CLASS is an internal class value that should not have been
+      exposed via a public API call.
+
+      In debug builds of the library, this can cause assert() function to
+      trip. In non-debug builds, it will produce normal library errors.
+
+      The new library behavior is for H5Sset_extent_none() to convert
+      the dataspace into one of type H5S_NULL, which is better handled
+      by the library and easier for developers to reason about.
+
+      (DER - 2020/07/27, HDFFV-11027)
+
+    - Fixed the segmentation fault when reading attributes with multiple threads
+
+      It was reported that the reading of attributes with variable length string
+      datatype will crash with segmentation fault particularly when the number of
+      threads is high (>16 threads).  The problem was due to the file pointer that
+      was set in the variable length string datatype for the attribute.  That file
+      pointer was already closed when the attribute was accessed.
+
+      The problem was fixed by setting the file pointer to the current opened file pointer
+      when the attribute was accessed.  Similar patch up was done before when reading
+      dataset with variable length string datatype.
+
+      (VC - 2020/07/13, HDFFV-11080)
+
+    - Fixed CVE-2018-17435
+
+      The tool h52gif produced a segfault when the size of an attribute message
+      was corrupted and caused a buffer overflow.
+
+      The problem was fixed by verifying the attribute message's size against the
+      buffer size before accessing the buffer.  h52gif was also fixed to display
+      the failure instead of silently exiting after the segfault was eliminated.
+
+      (BMR - 2020/6/19, HDFFV-10591)
+
+    - Reduce overhead for H5open(), which is involved in public symbols like
+      H5T_NATIVE_INT, etc.
+
+      (QAK - 2020/06/18)
+
+    - Cache last ID looked up for an ID type (dataset, datatype, file, etc),
+      improving performance when accessing the same ID repeatedly.
+
+      (QAK - 2020/06/11)
+
+    - Streamline I/O to a single element, improving performance for record
+      appends to chunked datasets.
+
+      (QAK - 2020/06/11)
+
+    - Remove redundant tagging of metadata cache entries for some chunked
+      dataset operations, slightly improving performance for chunked
+      datasets.
+
+      (QAK - 2020/06/10)
+
+    - Better detect selections with the same shape, improving performance for
+      some uses of H5DOappend (and other situations).
+
+      (QAK - 2020/06/07)
+
+    - Don't allocate an empty (0-dimensioned) chunked dataset's chunk
+      index, until the dataset's dimensions are increased.
+
+      (QAK - 2020/05/07)
+
+
+    Java Library
+    ------------
+    - JNI utility function does not handle new references.
+
+      The JNI utility function for converting reference data to string did
+      not use the new APIs. In addition to fixing that function, added new
+      java tests for using the new APIs.
+
+      (ADB - 2021/02/16, HDFFV-11212)
+
+    - The H5FArray.java class, in which virtually the entire execution time
+      is spent using the HDFNativeData method that converts from an array
+      of bytes to an array of the destination Java type.
+
+        1. Convert the entire byte array into a 1-d array of the desired type,
+           rather than performing 1 conversion per row;
+        2. Use the Java Arrays method copyOfRange to grab the section of the
+           array from (1) that is desired to be inserted into the destination array.
+
+      (PGT,ADB - 2020/12/29, HDFFV-10865)
+
+    Configuration
+    -------------
+    - Refactor CMake configure for Fortran
+
+      The Fortran configure tests for KINDs reused a single output file that was
+      read to form the Integer and Real Kinds defines. However, if config was run
+      more then once, the CMake completed variable prevented the tests from executing
+      again and the last value saved in the file was used to create the define.
+      Creating separate files for each KIND solved the issue.
+
+      In addition the test for H5_PAC_C_MAX_REAL_PRECISION was not pulling in
+      defines for proper operation and did not define H5_PAC_C_MAX_REAL_PRECISION
+      correctly for a zero value. This was fixed by supplying the required defines.
+      In addition it was moved from the Fortran specific HDF5UseFortran.camke file
+      to the C centric ConfigureChecks.cmake file.
+
+      (ADB - 2021/06/03)
+
+    - Move emscripten flag to compile flags
+
+      The emscripten flag, -O0, was removed from target_link_libraries command
+      to the correct target_compile_options command.
+
+      (ADB - 2021/04/26 HDFFV-11083)
+
+    - Remove arbitrary warning flag groups from CMake builds
+
+      The arbitrary groups were created to reduce the quantity of warnings being
+      reported that overwhelmed testing report systems. Considerable work has
+      been accomplished to reduce the warning count and these arbitrary groups
+      are no longer needed.
+      Also the default for all warnings, HDF5_ENABLE_ALL_WARNINGS, is now ON.
+
+      Visual Studio warnings C4100, C4706, and C4127 have been moved to
+      developer warnings, HDF5_ENABLE_DEV_WARNINGS, and are disabled for normal builds.
+
+      (ADB - 2021/03/22, HDFFV-11228)
+
+    - Reclassify CMake messages, to allow new modes and --log-level option
+
+      CMake message commands have a mode argument. By default, STATUS mode
+      was chosen for any non-error message. CMake version 3.15 added additional
+      modes, NOTICE, VERBOSE, DEBUG and TRACE. All message commands with a mode
+      of STATUS were reviewed and most were reclassified as VERBOSE. The new
+      mode was protected by a check for a CMake version of at least 3.15. If CMake
+      version 3.17 or above is used, the user can use the command line option
+      of "--log-level" to further restrict which message commands are displayed.
+
+      (ADB - 2021/01/11, HDFFV-11144)
+
+    - Fixes Autotools determination of the stat struct having an st_blocks field
+
+      A missing parenthesis in an autoconf macro prevented building the test
+      code used to determine if the stat struct contains the st_blocks field.
+      Now that the test functions correctly, the H5_HAVE_STAT_ST_BLOCKS #define
+      found in H5pubconf.h will be defined correctly on both the Autotools and
+      CMake. This #define is only used in the tests and does not affect the
+      HDF5 C library.
+
+      (DER - 2021/01/07, HDFFV-11201)
+
+    - Add missing ENV variable line to hdfoptions.cmake file
+
+      Using the build options to use system SZIP/ZLIB libraries need to also
+      specify the library root directory. Setting the {library}_ROOT ENV
+      variable was added to the hdfoptions.cmake file.
+
+      (ADB - 2020/10/19 HDFFV-11108)
+
+    - Fixed removal of Java lib files by "make uninstall"
+
+      "make uninstall" was not removing 5 Java files from the lib directory.
+
+      (LRK - 2020/08/24, HDFFV-10811)
+
+    - Stopped addition of szip header and include directory path for
+      incompatible libsz
+
+      szlib.h is the same for both 32-bit and 64-bit szip, and the header file
+      and its path were added to the HDF5 binary even though the configure
+      check of a function in libsz later failed and szip compression was not
+      enabled.  The header file and include path are now added only when the
+      libsz function passes the configure check.
+
+      (LRK - 2020/08/17, HDFFV-10830)
+
+
+    Tools
+    -----
+    - Changed how h5dump and h5ls identify long double.
+
+      Long double support is not consistent across platforms. Tools will always
+      identify long double as 128-bit [little/big]-endian float nn-bit precision.
+      New test file created for datasets with attributes for float, double and
+      long double. In addition any unknown integer or float datatype will now
+      also show the number of bits for precision.
+      These files are also used in the java tests.
+
+      (ADB - 2021/03/24, HDFFV-11229,HDFFV-11113)
+
+    - Fixed tools argument parsing.
+
+      Tools parsing used the length of the option from the long array to match
+      the option from the command line. This incorrectly matched a shorter long
+      name option that happened to be a subset of another long option.
+      Changed to match whole names.
+
+      (ADB - 2021/01/19, HDFFV-11106)
+
+    - Fixed a bug with h5repack ignoring the "-q" and "-z" command-line options
+
+        h5repack uses the -q and -z command-line options to specify the indexing
+        options for objects in the file when repacking. Previously, h5repack
+        would simply ignore any setting from these options. This has been fixed
+        so that h5repack will correctly interpret the following settings:
+
+          -q "name"           : Sort objects by name order
+          -q "creation_order" : Sort objects by link creation order
+          -z "ascending"      : Sort objects by ascending name/link creation order
+          -z "descending"     : Sort objects by descending name/link creation order
+
+        (JTH - 2020/04/16, HDFFV-11030)
+
+    - The tools library was updated by standardizing the error stack process.
+
+        General sequence is:
+          h5tools_setprogname(PROGRAMNAME);
+          h5tools_setstatus(EXIT_SUCCESS);
+          h5tools_init();
+          ... process the command-line (check for error-stack enable) ...
+          h5tools_error_report();
+          ... (do work) ...
+          h5diff_exit(ret);
+
+        (ADB - 2020/07/20, HDFFV-11066)
+
+    - h5diff fixed a command line parsing error.
+
+        h5diff would ignore the argument to -d (delta) if it is smaller than DBL_EPSILON.
+        The macro H5_DBL_ABS_EQUAL was removed and a direct value comparision was used.
+
+        (ADB - 2020/07/20, HDFFV-10897)
+
+    - h5diff added a command line option to ignore attributes.
+
+        h5diff would ignore all objects with a supplied path if the exclude-path argument is used.
+        Adding the exclude-attribute argument will only exclude attributes, with the supplied path,
+        from comparison.
+
+        (ADB - 2020/07/20, HDFFV-5935)
+
+    - h5diff added another level to the verbose argument to print filenames.
+
+        Added verbose level 3 that is level 2 plus the filenames. The levels are:
+          0 : Identical to '-v' or '--verbose'
+          1 : All level 0 information plus one-line attribute status summary
+          2 : All level 1 information plus extended attribute status report
+          3 : All level 2 information plus file names
+        (ADB - 2020/07/20, HDFFV-1005)
+
+
+    Fortran API
+    -----------
+    - Fixed configure issue when building HDF5 with NAG Fortran 7.0.
+
+      HDF5 now accounts for the addition of half-precision floating-point
+      in NAG 7.0 with a KIND=16.
+
+      (MSB - 2020/02/28, HDFFV-11033)
+
+
+    High-Level Library
+    ------------------
+    - Eliminated unnecessary code in H5DOappend(), improving its performance.
+
+      (QAK - 2020/06/05)
+
+
+    Fortran High-Level APIs
+    -----------------------
+    -
+
+
+    Documentation
+    -------------
+    - Updated doxygen comments with changes for release
+
+      (ADB - 2021/05/03)
+
+    - Fixed the dimension size description in the layout message table of the
+      file format specification section IV.A.2.i.
+
+      The layout message table described the dimension sizes starting from
+      Dimension 0 to Dimension #n.  This was incorrect because it would mean
+      the rank is n+1.
+
+      The dimension size entries were changed to starting from Dimension 1 to
+      Dimension #n.
+
+      (VC – 2020/06/09, HDFFV-11079)
+
+
+    F90 APIs
+    --------
+    - Fixed parallel make build failure due to a missing H5forkit dependency.
+
+      (MSB, 2021/03/31, HDFFV-11232)
+
+
+    C++ APIs
+    --------
+    - Added DataSet::operator=
+
+        Some compilers complain if the copy constructor is given explicitly
+        but the assignment operator is implicitly set to default.
+
+        (LN - 2021/05/19)
+
+
+    Testing
+    -------
+    - Stopped java/test/junit.sh.in installing libs for testing under ${prefix}
+
+      Lib files needed are now copied to a subdirectory in the java/test
+      directory, and on Macs the loader path for libhdf5.xxxs.so is changed
+      in the temporary copy of libhdf5_java.dylib.
+
+      (LRK - 2020/07/02, HDFFV-11063)
+
+
+Supported Platforms
+===================
+
+    Linux 3.10.0-327.10.1.el7   GNU C (gcc), Fortran (gfortran), C++ (g++)
+    #1 SMP x86_64 GNU/Linux       compilers:
+    (jelly/kituo/moohan)            Version 4.8.5 20150623 (Red Hat 4.8.5-4)
+                                    Version 4.9.3, 5.2.0, 7.1.0
+                                  Intel(R) C (icc), C++ (icpc), Fortran (icc)
+                                  compilers:
+                                     Version 17.0.0.098 Build 20160721
+                                  MPICH 3.2, 3.3
+
+    Windows 10 x64                Visual Studio 2015 w/ Intel Fortran 18 (cmake)
+                                  Visual Studio 2017 w/ Intel Fortran 19 (cmake)
+                                  Visual Studio 2019 w/ Intel Fortran 19 (cmake)
+                                  Visual Studio 2019 w/ MSMPI 10.1 (cmake)
+
+    MacOS High Sierra 10.13.6     Apple LLVM version 10.0.0 (clang-1000.10.44.4)
+    64-bit                        gfortran GNU Fortran (GCC) 6.3.0
+    (bear)                        Intel icc/icpc/ifort version 19.0.4
+
+    MacOS Big Sur 11.2            Apple clang version 12.0.5 (clang-1205.0.22.9)
+                                  gfortran GNU Fortran (Homebrew GCC 10.2.0_3) 10.2.0
+                                  Intel icc/icpc (ICC) 2021.1 Beta 20201112
+
+Tested Configuration Features Summary
+=====================================
+
+    In the tables below
+          y   = tested
+          n   = not tested in this release
+          C   = Cluster
+          W   = Workstation
+          x   = not working in this release
+          dna = does not apply
+          ( ) = footnote appears below second table
+          <blank> = testing incomplete on this feature or platform
+
+Platform                              C         F90/   F90      C++  zlib  SZIP
+                                      parallel  F2003  parallel
+Windows 10                              y        y/y    n        y    y     y
+Windows 10 x64                          y        y/y    n        y    y     y
+MacOS High Sierra 10.13.6 64-bit        n        y/y    n        y    y     y
+MacOS Big Sur 11.2 64-bit               n        y/y    n        y    y     y
+CentOS 6.7 Linux 2.6.18 x86_64 GNU      n        y/y    n        y    y     y
+CentOS 6.7 Linux 2.6.32 x86_64 PGI      n        y/y    n        y    y     y
+CentOS 7.2 Linux 2.6.32 x86_64 GNU      y        y/y    y        y    y     y
+CentOS 7.2 Linux 2.6.32 x86_64 Intel    n        y/y    n        y    y     y
+Linux 3.10.0-1127.10.1.1.ch6.ppc64le    n        y/n    n        y    y     y
+
+
+Platform                                 Shared  Shared    Shared    Thread-
+                                         C libs  F90 libs  C++ libs  safe
+Windows 10                                 y       y         y         y
+Windows 10 x64                             y       y         y         y
+MacOS High Sierra 10.13.6 64-bit           y       n         y         y
+MacOS Big Sur 11.2 64-bit                  y       n         y         y
+CentOS 6.7 Linux 2.6.18 x86_64 GNU         y       y         y         y
+CentOS 6.7 Linux 2.6.32 x86_64 PGI         y       y         y         n
+CentOS 7.2 Linux 2.6.32 x86_64 GNU         y       y         y         n
+CentOS 7.2 Linux 2.6.32 x86_64 Intel       y       y         y         n
+Linux 3.10.0-1127.10.1.1.ch6.ppc64le       y       y         y         n
+
+Compiler versions for each platform are listed in the preceding
+"Supported Platforms" table.
+
+
+More Tested Platforms
+=====================
+
+The following platforms are not supported but have been tested for this release.
+
+    Linux 2.6.32-573.22.1.el6    GNU C (gcc), Fortran (gfortran), C++ (g++)
+    #1 SMP x86_64 GNU/Linux       compilers:
+    (platypus)                 Version 4.4.7 20120313
+                                     Version 4.9.3, 5.3.0, 6.2.0
+                                  PGI C, Fortran, C++ for 64-bit target on
+                                  x86-64;
+                                      Version 19.10-0
+                                  MPICH 3.1.4 compiled with GCC 4.9.3
+
+    Linux 3.10.0-327.18.2.el7     GNU C (gcc) and C++ (g++) compilers
+    #1 SMP x86_64 GNU/Linux          Version 4.8.5 20150623 (Red Hat 4.8.5-4)
+    (jelly)                       with NAG Fortran Compiler Release 6.1(Tozai)
+                                  GCC Version 7.1.0
+                                  OpenMPI 3.0.0-GCC-7.2.0-2.29
+                                  Intel(R) C (icc) and C++ (icpc) compilers
+                                     Version 17.0.0.098 Build 20160721
+                                  with NAG Fortran Compiler Release 6.1(Tozai)
+                                  PGI C (pgcc), C++ (pgc++), Fortran (pgf90)
+                                  compilers:
+                                     Version 18.4, 19.4
+                                  MPICH 3.3
+                                  OpenMPI 2.1.5, 3.1.3, 4.0.0
+
+    Linux 3.10.0-327.10.1.el7     MPICH 3.1.4 compiled with GCC 4.9.3
+    #1 SMP x86_64 GNU/Linux
+    (moohan)
+
+    Linux-3.10.0-1127.0.0.1chaos  openmpi/4.0.0
+    #1 SMP x86_64 GNU/Linux           clang/6.0.0, 11.0.1
+    (quartz)                          gcc/7.3.0, 8.3.0
+                                      intel/16.0.4, 18.0.2, 19.0.4
+
+    Linux-4.14.0-115.10.1.1       spectrum-mpi/rolling-release
+    #1 SMP ppc64le GNU/Linux          clang/7.1.0, ibm-11.0.1
+    (lassen)                          gcc/4.9.3, 8.3.1
+                                      xl/2019.02.07, 2021.03.11
+
+    Linux-4.12.14-150.52-default  cray-mpich/7.7.10
+    #1 SMP x86_64 GNU/Linux           gcc/8.3.0
+    (cori)                            intel/19.0.3
+
+    Linux-4.4.180-94.107-default  cray-mpich/7.7.16
+    # 1SMP x86_64 GNU/Linux           gcc/7.3.0, 8.3.0, 10.2.0
+    (mutrino)                         intel/17.0.4, 18.0.5, 19.1.3
+
+    Linux-3.10.0-                 spectrum-mpi/rolling-release
+    1127.10.1.1chaos.ch6.ppc64le       clang/7.1.0, 11.0.1
+    #1 SMP ppc64le GNU/Linux           gcc/4.9.3,8.3.1
+    (ray)                              xl/2019.08.20,2021.03.11
+
+    Fedora33 5.11.18-200.fc33.x86_64
+    #1 SMP x86_64  GNU/Linux         GNU gcc (GCC) 10.3.1 20210422 (Red Hat 10.3.1-1)
+                                     GNU Fortran (GCC) 10.3.1 20210422 (Red Hat 10.3.1-1)
+                                     clang version 11.0.0 (Fedora 11.0.0-2.fc33)
+                                     (cmake and autotools)
+
+    Ubuntu20.04 5.8.0-53-generic-x86_64
+    #60~20.04-Ubuntu SMP x86_64  GNU/Linux GNU gcc (GCC) 9.3.0-17ubuntu1
+                                     GNU Fortran (GCC) 9.3.0-17ubuntu1
+                                     clang version 10.0.0-4ubuntu1
+                                     (cmake and autotools)
+
+    Ubuntu20.10 5.8.0-53-generic-x86_64
+    #60-Ubuntu SMP x86_64  GNU/Linux GNU gcc (GCC) 10.2.0-13ubuntu1
+                                     GNU Fortran (GCC) 10.2.0-13ubuntu1
+                                     Ubuntu clang version 11.0.0-2
+                                     (cmake and autotools)
+
+    SUSE15sp2 5.3.18-22-default
+    #1 SMP x86_64  GNU/Linux         GNU gcc (SUSE Linux) 7.5.0
+                                     GNU Fortran (SUSE Linux) 7.5.0
+                                     clang version 7.0.1 (tags/RELEASE_701/final 349238)
+                                     (cmake and autotools)
+
+    Mac OS X El Capitan 10.11.6   Apple clang/clang++ version 7.3.0 from Xcode 7.3
+    64-bit                        gfortran GNU Fortran (GCC) 5.2.0
+    (osx1011dev/osx1011test)      Intel icc/icpc/ifort version 16.0.2
+
+
+Known Problems
+==============
+
+    testflushrefresh.sh will fail when run with "make check-passthrough-vol"
+    on centos7, with 3 Errors/Segmentation faults.  These will not occur when
+    run with "make check".  See https://github.com/HDFGroup/hdf5/issues/673
+    for details.
+
+    The t_bigio test fails on several HPC platforms, generally by timeout with
+    OpenMPI 4.0.0 or with this error from spectrum-mpi:
+        *** on communicator MPI_COMM_WORLD
+        *** MPI_ERR_COUNT: invalid count argument
+
+    CMake files do not behave correctly with paths containing spaces.
+    Do not use spaces in paths because the required escaping for handling spaces
+    results in very complex and fragile build files.
+    ADB - 2019/05/07
+
+    At present, metadata cache images may not be generated by parallel
+    applications.  Parallel applications can read files with metadata cache
+    images, but since this is a collective operation, a deadlock is possible
+    if one or more processes do not participate.
+
+    CPP ptable test fails on both VS2017 and VS2019 with Intel compiler, JIRA
+    issue: HDFFV-10628.  This test will pass with VS2015 with Intel compiler.
+
+    The subsetting option in ph5diff currently will fail and should be avoided.
+    The subsetting option works correctly in serial h5diff.
+
+    Known problems in previous releases can be found in the HISTORY*.txt files
+    in the HDF5 source. Please report any new problems found to
+    help@hdfgroup.org.
+
+
+CMake vs. Autotools installations
+=================================
+
+While both build systems produce similar results, there are differences.
+Each system produces the same set of folders on linux (only CMake works
+on standard Windows); bin, include, lib and share. Autotools places the
+COPYING and RELEASE.txt file in the root folder, CMake places them in
+the share folder.
+
+The bin folder contains the tools and the build scripts. Additionally, CMake
+creates dynamic versions of the tools with the suffix "-shared". Autotools
+installs one set of tools depending on the "--enable-shared" configuration
+option.
+  build scripts
+  -------------
+  Autotools: h5c++, h5cc, h5fc
+  CMake: h5c++, h5cc, h5hlc++, h5hlcc
+
+The include folder holds the header files and the fortran mod files. CMake
+places the fortran mod files into separate shared and static subfolders,
+while Autotools places one set of mod files into the include folder. Because
+CMake produces a tools library, the header files for tools will appear in
+the include folder.
+
+The lib folder contains the library files, and CMake adds the pkgconfig
+subfolder with the hdf5*.pc files used by the bin/build scripts created by
+the CMake build. CMake separates the C interface code from the fortran code by
+creating C-stub libraries for each Fortran library. In addition, only CMake
+installs the tools library. The names of the szip libraries are different
+between the build systems.
+
+The share folder will have the most differences because CMake builds include
+a number of CMake specific files for support of CMake's find_package and support
+for the HDF5 Examples CMake project.
+
+
+
 %%%%1.12.0%%%%
 
 HDF5 version 1.12.0 released on 2020-02-28