HDF5 version 1.12.1-4 currently under development ================================================================================ INTRODUCTION ============ This document describes the new features introduced in the HDF5 1.12.0 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-alpha1 - Supported Platforms - Tested Configuration Features Summary - More Tested Platforms - Known Problems - CMake vs. Autotools installations New Features ============ Configuration: ------------- - Add 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) (barcode - 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, https://github.com/HDFGroup/hdf5/issues/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) - CMake option to use MSVC naming conventions with MinGW HDF5_MSVC_NAMING_CONVENTION option enable to use 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) - 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. (ADB - 2020/03/24, TRILAB-192) Library: -------- - 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) - Added two new API routines for tracking library memory use: H5get_alloc_stats() and H5get_free_list_sizes(). (QAK - 2020/03/25) 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) 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 ================================================== - Bug Fixes since HDF5-1.12.0 release =================================== Library ------- - 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) - 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) - 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) - 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 ------------- - 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) Tools ----- - 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) 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 ------------- - F90 APIs -------- - C++ APIs -------- - 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 2.6.32-696.16.1.el6.ppc64 gcc (GCC) 4.4.7 20120313 (Red Hat 4.4.7-18) #1 SMP ppc64 GNU/Linux g++ (GCC) 4.4.7 20120313 (Red Hat 4.4.7-18) (ostrich) GNU Fortran (GCC) 4.4.7 20120313 (Red Hat 4.4.7-18) IBM XL C/C++ V13.1 IBM XL Fortran V15.1 Linux 3.10.0-327.10.1.el7 GNU C (gcc), Fortran (gfortran), C++ (g++) #1 SMP x86_64 GNU/Linux compilers: (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 3.1.4 Linux-3.10.0- spectrum-mpi/rolling-release with cmake>3.10 and 862.14.4.1chaos.ch6.ppc64le clang/3.9,8.0 #1 SMP ppc64le GNU/Linux gcc/7.3 (ray) xl/2016,2019 Linux 3.10.0- openmpi/3.1,4.0 with cmake>3.10 and 957.12.2.1chaos.ch6.x86_64 clang 5.0 #1 SMP x86_64 GNU/Linux gcc/7.3,8.2 (serrano) intel/17.0,18.0/19.0 Linux 3.10.0- openmpi/3.1/4.0 with cmake>3.10 and 1062.1.1.1chaos.ch6.x86_64 clang/3.9,5.0,8.0 #1 SMP x86_64 GNU/Linux gcc/7.3,8.1,8.2 (chama,quartz) intel/16.0,18.0,19.0 Linux 4.4.180-94.100-default cray-mpich/7.7.6 with PrgEnv-*/6.0.5, cmake>3.10 and #1 SMP x86_64 GNU/Linux gcc/7.2.0,8.2.0 (mutrino) intel/17.0,18.0 Linux 4.14.0- spectrum-mpi/rolling-release with cmake>3.10 and 49.18.1.bl6.ppc64le clang/6.0,8.0 #1 SMP ppc64le GNU/Linux gcc/7.3 (lassen) xl/2019 SunOS 5.11 32- and 64-bit Sun C 5.12 SunOS_sparc (emu) Sun Fortran 95 8.6 SunOS_sparc Sun C++ 5.12 SunOS_sparc 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) Mac OS X Yosemite 10.10.5 Apple clang/clang++ version 6.1 from Xcode 7.0 64-bit gfortran GNU Fortran (GCC) 4.9.2 (osx1010dev/osx1010test) Intel icc/icpc/ifort version 15.0.3 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 Mac OS High Sierra 10.13.6 Apple LLVM version 10.0.0 (clang/clang++-1000.10.44.4) 64-bit gfortran GNU Fortran (GCC) 6.3.0 (bear) Intel icc/icpc/ifort version 19.0.4 Mac OS Mojave 10.14.6 Apple LLVM version 10.0.1 (clang/clang++-1001.0.46.4) 64-bit gfortran GNU Fortran (GCC) 6.3.0 (bobcat) Intel icc/icpc/ifort version 19.0.4 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 = testing incomplete on this feature or platform Platform C F90/ F90 C++ zlib SZIP parallel F2003 parallel Solaris2.11 32-bit n y/y n y y y Solaris2.11 64-bit n y/n n y y y Windows 10 y y/y n y y y Windows 10 x64 y y/y n y y y Mac OS X Mountain Lion 10.8.5 64-bit n y/y n y y y Mac OS X Mavericks 10.9.5 64-bit n y/y n y y ? Mac OS X Yosemite 10.10.5 64-bit n y/y n y y ? Mac OS X El Capitan 10.11.6 64-bit n y/y n y y ? CentOS 6.7 Linux 2.6.18 x86_64 GNU n y/y n y y y CentOS 6.7 Linux 2.6.18 x86_64 Intel 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 2.6.32-573.18.1.el6.ppc64 n y/n n y y y Platform Shared Shared Shared Thread- C libs F90 libs C++ libs safe Solaris2.11 32-bit y y y y Solaris2.11 64-bit y y y y Windows 10 y y y y Windows 10 x64 y y y y Mac OS X Mountain Lion 10.8.5 64-bit y n y y Mac OS X Mavericks 10.9.5 64-bit y n y y Mac OS X Yosemite 10.10.5 64-bit y n y y Mac OS X El Capitan 10.11.6 64-bit y n y y CentOS 6.7 Linux 2.6.18 x86_64 GNU y y y y CentOS 6.7 Linux 2.6.18 x86_64 Intel y y y n 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 2.6.32-573.18.1.el6.ppc64 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: (mayll/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 17.10-0 Intel(R) C (icc), C++ (icpc), Fortran (icc) compilers: Version 17.0.4.196 Build 20170411 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 Fedora33 5.10.10-200.fc33.x86_64 #1 SMP x86_64 GNU/Linux GNU gcc (GCC) 10.2.1 20201125 (Red Hat 10.2.1-9) GNU Fortran (GCC) 10.2.1 20201125 (Red Hat 10.2.1-9) clang version 11.0.0 (Fedora 11.0.0-2.fc33) (cmake and autotools) Ubuntu20.10 5.8.0-41-generic-x86_64 #46-Ubuntu SMP x86_64 GNU/Linux GNU gcc (GCC) 10.2.0-13ubuntu1 GNU Fortran (GCC) 10.2.0-13ubuntu1 (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) Known Problems ============== 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. 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.