Merge branch 'develop' of https://bitbucket.hdfgroup.org/scm/hdffv/hdf5 into develop

13 files changed, 2068 insertions, 130 deletions

diff --git a/MANIFEST b/MANIFEST
index 6c2018a..7cb2cfd 100644
--- a/MANIFEST
+++ b/MANIFEST
@@ -461,8 +461,9 @@
 ./release_docs/INSTALL_parallel
 ./release_docs/INSTALL_Warnings.txt
 ./release_docs/INSTALL_Windows.txt
-./release_docs/RELEASE.txt
+./release_docs/README_HDF5_CMake
 ./release_docs/README_HPC
+./release_docs/RELEASE.txt
 ./release_docs/USING_HDF5_CMake.txt
 ./release_docs/USING_HDF5_VS.txt
 
diff --git a/release_docs/HISTORY-1_10.txt b/release_docs/HISTORY-1_10.txt
index 9887a54..ad8beb2 100644
--- a/release_docs/HISTORY-1_10.txt
+++ b/release_docs/HISTORY-1_10.txt
@@ -3,6 +3,8 @@ HDF5 History
 
 This file contains development history of the HDF5 1.10 branch
 
+06.      Release Information for hdf5-1.10.4
+05.      Release Information for hdf5-1.10.3
 04.      Release Information for hdf5-1.10.2
 03.      Release Information for hdf5-1.10.1
 02.      Release Information for hdf5-1.10.0-patch1 
@@ -10,6 +12,1039 @@ This file contains development history of the HDF5 1.10 branch
 
 [Search on the string '%%%%' for section breaks of each release.]
 
+%%%%1.10.4%%%%
+
+HDF5 version 1.10.4 released on 2018-10-05
+================================================================================
+
+
+INTRODUCTION
+
+This document describes the differences between this release and the previous
+HDF5 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 each
+final 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/
+
+Changes from Release to Release and New Features in the HDF5-1.10.x release series
+can be found at:
+
+     https://portal.hdfgroup.org/display/HDF5/HDF5+Application+Developer%27s+Guide
+
+If you have any questions or comments, please send them to the HDF Help Desk:
+
+     help@hdfgroup.org
+
+
+CONTENTS
+
+- Bug Fixes since HDF5-1.10.3
+- Supported Platforms
+- Tested Configuration Features Summary
+- More Tested Platforms
+- Known Problems
+- CMake vs. Autotools installations
+
+
+New Features
+============
+
+    Configuration:
+    -------------
+    - Add toolchain and cross-compile support
+
+      Added info on using a toolchain file to INSTALL_CMAKE.txt. A
+      toolchain file is also used in cross-compiling, which requires
+      CMAKE_CROSSCOMPILING_EMULATOR to be set. To help with cross-compiling
+      the fortran configure process, the HDF5UseFortran.cmake file macros
+      were improved. Fixed a Fortran configure file issue that incorrectly
+      used #cmakedefine instead of #define.
+
+      (ADB - 2018/10/04, HDFFV-10594)
+
+    - Add warning flags for Intel compilers
+
+      Identified Intel compiler specific warnings flags that should be used
+      instead of GNU flags.
+
+      (ADB - 2018/10/04, TRILABS-21)
+
+    - Add default rpath to targets
+
+      Default rpaths should be set in shared executables and
+      libraries to allow the use of loading dependent libraries
+      without requiring LD_LIBRARY_PATH to be set. The default
+      path should be relative using @rpath on osx and $ORIGIN
+      on linux. Windows is not affected.
+
+      (ADB - 2018/09/26, HDFFV-10594)
+
+    Library:
+    --------
+    - Allow pre-generated H5Tinit.c and H5make_libsettings.c to be used.
+
+      Rather than always running H5detect and generating H5Tinit.c and
+      H5make_libsettings.c, supply a location for those files.
+
+      (ADB - 2018/09/18, HDFFV-10332)
+
+
+Bug Fixes since HDF5-1.10.3 release
+==================================
+
+    Library
+    -------
+    - Allow H5detect and H5make_libsettings to take a file as an argument.
+
+      Rather than only writing to stdout, add a command argument to name
+      the file that H5detect and H5make_libsettings will use for output.
+      Without an argument, stdout is still used, so backwards compatibility
+      is maintained.
+
+      (ADB - 2018/09/05, HDFFV-9059)
+
+    - A bug was discovered in the parallel library where an application
+      would hang if a collective read/write of a chunked dataset occurred
+      when collective metadata reads were enabled and some of the ranks
+      had no selection in the dataset's dataspace. The ranks which had no
+      selection in the dataset's dataspace called H5D__chunk_addrmap() to
+      retrieve the lowest chunk address in the dataset. This is because we
+      require reads/writes to be performed in strictly non-decreasing order
+      of chunk address in the file.
+
+      When the chunk index used was a version 1 or 2 B-tree, these
+      non-participating ranks would issue a collective MPI_Bcast() call
+      that the participating ranks would not issue, causing the hang. Since
+      the non-participating ranks are not actually reading/writing anything,
+      the H5D__chunk_addrmap() call can be safely removed and the address used
+      for the read/write can be set to an arbitrary number (0 was chosen).
+
+      (JTH - 2018/08/25, HDFFV-10501)
+
+    Java Library:
+    ----------------
+    - JNI native library dependencies
+    
+      The build for the hdf5_java native library used the wrong
+      hdf5 target library for CMake builds. Correcting the hdf5_java
+      library to build with the shared hdf5 library required testing
+      paths to change also.
+
+      (ADB - 2018/08/31, HDFFV-10568)
+
+    - Java iterator callbacks
+
+      Change global callback object to a small stack structure in order
+      to fix a runtime crash. This crash was discovered when iterating
+      through a file with nested group members. The global variable
+      visit_callback is overwritten when recursion starts. When recursion
+      completes, visit_callback will be pointing to the wrong callback method.
+
+      (ADB - 2018/08/15, HDFFV-10536)
+
+    - Java HDFLibraryException class
+
+      Change parent class from Exception to RuntimeException.
+
+      (ADB - 2018/07/30, HDFFV-10534)
+
+    - JNI Read and Write
+
+      Refactored variable-length functions, H5DreadVL and H5AreadVL,
+      to correct dataset and attribute reads. New write functions,
+      H5DwriteVL and H5AwriteVL, are under construction.
+
+      (ADB - 2018/06/02, HDFFV-10519)
+
+
+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, Version 5.2.0
+                                  Intel(R) C (icc), C++ (icpc), Fortran (icc)
+                                  compilers:
+                                     Version 17.0.0.098 Build 20160721
+                                  MPICH 3.1.4 compiled with GCC 4.9.3
+
+    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 7                     Visual Studio 2015 w/ Intel Fortran 16 (cmake)
+
+    Windows 7 x64                 Visual Studio 2012 w/ Intel Fortran 15 (cmake)
+                                  Visual Studio 2013 w/ Intel Fortran 15 (cmake)
+                                  Visual Studio 2015 w/ Intel Fortran 16 (cmake)
+                                  Visual Studio 2015 w/ Intel C, Fortran 2017 (cmake)
+                                  Visual Studio 2015 w/ MSMPI 8 (cmake)
+
+    Windows 10                    Visual Studio 2015 w/ Intel Fortran 18 (cmake)
+
+    Windows 10 x64                Visual Studio 2015 w/ Intel Fortran 18 (cmake)
+                                  Visual Studio 2017 w/ Intel Fortran 18 (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 Sierra 10.12.6         Apple LLVM version 8.1.0 (clang/clang++-802.0.42)
+    64-bit                        gfortran GNU Fortran (GCC) 7.1.0
+    (kite)                        Intel icc/icpc/ifort version 17.0.2
+
+
+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
+Solaris2.11 32-bit                      n        y/y    n        y    y     y
+Solaris2.11 64-bit                      n        y/n    n        y    y     y
+Windows 7                               y        y/y    n        y    y     y
+Windows 7 x64                           y        y/y    y        y    y     y
+Windows 7 Cygwin                        n        y/n    n        y    y     y
+Windows 7 x64 Cygwin                    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 Mavericks 10.9.5 64-bit        n        y/y    n        y    y     y
+Mac OS X Yosemite 10.10.5 64-bit        n        y/y    n        y    y     y
+Mac OS X El Capitan 10.11.6 64-bit      n        y/y    n        y    y     y
+Mac OS Sierra 10.12.6 64-bit            n        y/y    n        y    y     y
+CentOS 7.2 Linux 3.10.0 x86_64 PGI      n        y/y    n        y    y     y
+CentOS 7.2 Linux 3.10.0 x86_64 GNU      y        y/y    y        y    y     y
+CentOS 7.2 Linux 3.10.0 x86_64 Intel    n        y/y    n        y    y     y
+Linux 2.6.32-573.18.1.el6.ppc64         n        y/y    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 7                                  y       y         y         y
+Windows 7 x64                              y       y         y         y
+Windows 7 Cygwin                           n       n         n         y
+Windows 7 x64 Cygwin                       n       n         n         y
+Windows 10                                 y       y         y         y
+Windows 10 x64                             y       y         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
+Mac OS Sierra 10.12.6 64-bit               y       n         y         y
+CentOS 7.2 Linux 3.10.0 x86_64 PGI         y       y         y         n
+CentOS 7.2 Linux 3.10.0 x86_64 GNU         y       y         y         y
+CentOS 7.2 Linux 3.10.0 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, 
+                                     3.1.0-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)
+
+    Linux 3.10.0-327.10.1.el7     MPICH 3.2 compiled with GCC 5.3.0
+    #1 SMP x86_64 GNU/Linux
+    (moohan)
+
+    Linux 2.6.32-573.18.1.el6.ppc64  MPICH mpich 3.1.4 compiled with
+    #1 SMP ppc64 GNU/Linux           IBM XL C/C++ for Linux, V13.1
+    (ostrich)                        and IBM XL Fortran for Linux, V15.1
+
+    Debian 8.4 3.16.0-4-amd64 #1 SMP Debian 3.16.36-1 x86_64 GNU/Linux
+                                  gcc, g++ (Debian 4.9.2-10) 4.9.2
+                                  GNU Fortran (Debian 4.9.2-10) 4.9.2
+                                  (cmake and autotools)
+
+    Fedora 24  4.7.2-201.fc24.x86_64 #1 SMP x86_64 x86_64 x86_64 GNU/Linux
+                                  gcc, g++ (GCC) 6.1.1 20160621
+                                      (Red Hat 6.1.1-3)
+                                  GNU Fortran (GCC) 6.1.1 20160621
+                                      (Red Hat 6.1.1-3)
+                                  (cmake and autotools)
+
+    Ubuntu 16.04.1 4.4.0-38-generic #57-Ubuntu SMP x86_64 GNU/Linux
+                                  gcc, g++ (Ubuntu 5.4.0-6ubuntu1~16.04.2)
+                                      5.4.0 20160609
+                                  GNU Fortran (Ubuntu 5.4.0-6ubuntu1~16.04.2)
+                                      5.4.0 20160609
+                                  (cmake and autotools)
+
+
+Known Problems
+==============
+
+    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.
+
+    Three tests fail with OpenMPI 3.0.0/GCC-7.2.0-2.29:
+        testphdf5 (ecdsetw, selnone, cchunk1, cchunk3, cchunk4, and actualio)
+        t_shapesame (sscontig2)
+        t_pflush1/fails on exit
+    The first two tests fail attempting collective writes.
+
+    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.
+
+%%%%1.10.3%%%%
+
+HDF5 version 1.10.3 released on 2018-08-21
+================================================================================
+
+
+INTRODUCTION
+
+This document describes the differences between this release and the previous
+HDF5 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 each
+final 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/
+
+Changes from Release to Release and New Features in the HDF5-1.10.x release series
+can be found at:
+
+     https://portal.hdfgroup.org/display/HDF5/HDF5+Application+Developer%27s+Guide
+
+If you have any questions or comments, please send them to the HDF Help Desk:
+
+     help@hdfgroup.org
+
+
+CONTENTS
+
+- New Features
+- Bug Fixes since HDF5-1.10.2
+- Supported Platforms
+- Tested Configuration Features Summary
+- More Tested Platforms
+- Known Problems
+- CMake vs. Autotools installations
+
+
+New Features
+============
+
+    Library
+    -------
+    - Moved the H5DOread/write_chunk() API calls to H5Dread/write_chunk()
+
+      The functionality of the direct chunk I/O calls in the high-level
+      library has been moved to the H5D package in the main library. This
+      will allow using those functions without building the high-level
+      library. The parameters and functionality of the H5D calls are
+      identical to the H5DO calls.
+
+      The original H5DO high-level API calls have been retained, though
+      they are now just wrappers for the H5D calls. They are marked as
+      deprecated and are only available when the library is built with
+      deprecated functions. New code should use the H5D calls for this
+      reason.
+
+      As a part of this work, the following symbols from H5Dpublic.h are no
+      longer used:
+
+        H5D_XFER_DIRECT_CHUNK_WRITE_FLAG_NAME
+        H5D_XFER_DIRECT_CHUNK_WRITE_FILTERS_NAME
+        H5D_XFER_DIRECT_CHUNK_WRITE_OFFSET_NAME
+        H5D_XFER_DIRECT_CHUNK_WRITE_DATASIZE_NAME
+        H5D_XFER_DIRECT_CHUNK_READ_FLAG_NAME
+        H5D_XFER_DIRECT_CHUNK_READ_OFFSET_NAME
+        H5D_XFER_DIRECT_CHUNK_READ_FILTERS_NAME
+
+      And properties with these names are no longer stored in the dataset
+      transfer property lists. The symbols are still defined in H5Dpublic.h,
+      but only when the library is built with deprecated symbols.
+
+      (DER - 2018/05/04)
+
+    Configuration:
+    -------------
+    - Add missing USE_110_API_DEFAULT option.
+
+      Option USE_110_API_DEFAULT sets the default version of
+      versioned APIs. The bin/makevers perl script did not set
+      the maxidx variable correctly when the 1.10 branch was
+      created. This caused the versioning process to always use
+      the latest version of any API.
+
+      (ADB - 2018/08/17, HDFFV-10552)
+
+    - Added configuration checks for the following MPI functions:
+
+      MPI_Mprobe - Used for the Parallel Compression feature
+      MPI_Imrecv - Used for the Parallel Compression feature
+
+      MPI_Get_elements_x - Used for the "big Parallel I/O" feature
+      MPI_Type_size_x - Used for the "big Parallel I/O" feature
+
+      (JTH - 2018/08/02, HDFFV-10512)
+
+    - Added section to the libhdf5.settings file to indicate
+      the status of the Parallel Compression and "big Parallel I/O"
+      features.
+
+      (JTH - 2018/08/02, HDFFV-10512)
+
+    - Add option to execute swmr shell scripts from CMake.
+
+      Option TEST_SHELL_SCRIPTS redirects processing into a
+      separate ShellTests.cmake file for UNIX types. The tests
+      execute the shell scripts if a SH program is found.
+
+      (ADB - 2018/07/16)
+
+
+    C++ Library:
+    ------------
+    - New wrappers
+
+      Added the following items:
+
+      + Class DSetAccPropList for the dataset access property list.
+
+      + Wrapper for H5Dget_access_plist to class DataSet
+        // Gets the access property list of this dataset.
+        DSetAccPropList getAccessPlist() const;
+
+      + Wrappers for H5Pset_chunk_cache and H5Pget_chunk_cache to class DSetAccPropList
+        // Sets the raw data chunk cache parameters.
+        void setChunkCache(size_t rdcc_nslots, size_t rdcc_nbytes, double rdcc_w0)
+
+        // Retrieves the raw data chunk cache parameters.
+        void getChunkCache(size_t &rdcc_nslots, size_t &rdcc_nbytes, double &rdcc_w0)
+
+      + New operator!= to class DataType (HDFFV-10472)
+        // Determines whether two datatypes are not the same.
+        bool operator!=(const DataType& compared_type)
+
+      + Wrappers for H5Oget_info2, H5Oget_info_by_name2, and H5Oget_info_by_idx2
+        (HDFFV-10458)
+
+        // Retrieves information about an HDF5 object.
+        void getObjinfo(H5O_info_t& objinfo, unsigned fields = H5O_INFO_BASIC) const;
+
+        // Retrieves information about an HDF5 object, given its name.
+        void getObjinfo(const char* name, H5O_info_t& objinfo,
+                unsigned fields = H5O_INFO_BASIC,
+                const LinkAccPropList& lapl = LinkAccPropList::DEFAULT) const;
+        void getObjinfo(const H5std_string& name, H5O_info_t& objinfo,
+                unsigned fields = H5O_INFO_BASIC,
+                const LinkAccPropList& lapl = LinkAccPropList::DEFAULT) const;
+
+        // Retrieves information about an HDF5 object, given its index.
+        void getObjinfo(const char* grp_name, H5_index_t idx_type,
+                H5_iter_order_t order, hsize_t idx, H5O_info_t& objinfo,
+                unsigned fields = H5O_INFO_BASIC,
+                const LinkAccPropList& lapl = LinkAccPropList::DEFAULT) const;
+        void getObjinfo(const H5std_string& grp_name, H5_index_t idx_type,
+                H5_iter_order_t order, hsize_t idx, H5O_info_t& objinfo,
+                unsigned fields = H5O_INFO_BASIC,
+                const LinkAccPropList& lapl = LinkAccPropList::DEFAULT) const;
+
+      (BMR - 2018/07/22, HDFFV-10150, HDFFV-10458, HDFFV-1047)
+
+
+    Java Library:
+    ----------------
+    - Java HDFLibraryException class
+
+      Change parent class from Exception to RuntimeException.
+
+      (ADB - 2018/07/30, HDFFV-10534)
+
+    - JNI Read and Write
+
+      Refactored variable-length functions, H5DreadVL and H5AreadVL,
+      to correct dataset and attribute reads. New write functions,
+      H5DwriteVL and H5AwriteVL, are under construction.
+
+      (ADB - 2018/06/02, HDFFV-10519)
+
+
+Bug Fixes since HDF5-1.10.2 release
+==================================
+
+    Library
+    -------
+    - Performance issue with H5Oget_info
+
+      H5Oget_info family of routines retrieves information for an object such
+      as object type, access time, number of attributes, and storage space etc.
+      Retrieving all such information regardless is an overkill and causes
+      performance issue when doing so for many objects.
+
+      Add an additional parameter "fields" to the the H5Oget_info family of routines
+      indicating the type of information to be retrieved.  The same is done to
+      the H5Ovisit family of routines which recursively visits an object
+      returning object information in a callback function.  Both sets of routines
+      are versioned and the corresponding compatibility macros are added.
+
+      The version 2 names of the two sets of routines are:
+        (1) H5Oget_info2, H5Oget_info_by_idx2, H5Oget_info_by_name2
+        (2) H5Ovisit2, H5Ovisit_by_name2
+
+      (VC - 2018/08/15, HDFFV-10180)
+
+    - Test failure due to metadata size in test/vds.c
+
+      The size of metadata from test_api_get_ex_dcpl() in test/vds.c is not as expected
+      because the latest format should be used when encoding the layout for VDS.
+
+      Set the latest format in a temporary fapl and pass the setting to the routines that
+      encode the dataset selection for VDS.
+
+      (VC - 2018/08/14 HDFFV-10469)
+
+    - Java HDF5LibraryException class
+
+      The error minor and major values would be lost after the
+      constructor executed.
+
+      Created two local class variables to hold the values obtained during
+      execution of the constructor. Refactored the class functions to retrieve
+      the class values rather then calling the native functions.
+      The native functions were renamed and called only during execution
+      of the constructor.
+      Added error checking to calling class constructors in JNI classes.
+
+      (ADB - 2018/08/06, HDFFV-10544)
+
+    - Added checks of the defined MPI_VERSION to guard against usage of
+      MPI-3 functions in the Parallel Compression and "big Parallel I/O"
+      features when HDF5 is built with MPI-2. Previously, the configure
+      step would pass but the build itself would fail when it could not
+      locate the MPI-3 functions used.
+
+      As a result of these new checks, HDF5 can again be built with MPI-2,
+      but the Parallel Compression feature will be disabled as it relies
+      on the MPI-3 functions used.
+
+      (JTH - 2018/08/02, HDFFV-10512)
+
+    - User's patches: CVEs
+
+      The following patches have been applied:
+
+      CVE-2018-11202 - NULL pointer dereference was discovered in
+                       H5S_hyper_make_spans in H5Shyper.c (HDFFV-10476)
+        https://security-tracker.debian.org/tracker/CVE-2018-11202
+        https://cve.mitre.org/cgi-bin/cvename.cgi?name=3DCVE-2018-11202
+
+      CVE-2018-11203 - A division by zero was discovered in
+                       H5D__btree_decode_key in H5Dbtree.c (HDFFV-10477)
+        https://security-tracker.debian.org/tracker/CVE-2018-11203
+        https://cve.mitre.org/cgi-bin/cvename.cgi?name=3DCVE-2018-11203
+
+      CVE-2018-11204 - A NULL pointer dereference was discovered in
+                       H5O__chunk_deserialize in H5Ocache.c (HDFFV-10478)
+        https://security-tracker.debian.org/tracker/CVE-2018-11204
+        https://cve.mitre.org/cgi-bin/cvename.cgi?name=3DCVE-2018-11204
+
+      CVE-2018-11206 - An out of bound read was discovered in
+                       H5O_fill_new_decode and H5O_fill_old_decode in H5Ofill.c
+                       (HDFFV-10480)
+        https://security-tracker.debian.org/tracker/CVE-2018-11206
+        https://cve.mitre.org/cgi-bin/cvename.cgi?name=3DCVE-2018-11206
+
+      CVE-2018-11207 - A division by zero was discovered in
+                       H5D__chunk_init in H5Dchunk.c  (HDFFV-10481)
+        https://security-tracker.debian.org/tracker/CVE-2018-11207
+        https://cve.mitre.org/cgi-bin/cvename.cgi?name=3DCVE-2018-11207
+
+      (BMR - 2018/7/22, PR#s: 1134 and 1139,
+       HDFFV-10476, HDFFV-10477, HDFFV-10478, HDFFV-10480, HDFFV-10481)
+
+    - H5Adelete
+
+      H5Adelete failed when deleting the last "large" attribute that
+      is stored densely via fractal heap/v2 b-tree.
+
+      After removing the attribute, update the ainfo message.  If the
+      number of attributes goes to zero, remove the message.
+
+      (VC - 2018/07/20, HDFFV-9277)
+
+    - A bug was discovered in the parallel library which caused partial
+      parallel reads of filtered datasets to return incorrect data. The
+      library used the incorrect dataspace for each chunk read, causing
+      the selection used in each chunk to be wrong.
+
+      The bug was not caught during testing because all of the current
+      tests which do parallel reads of filtered data read all of the data
+      using an H5S_ALL selection. Several tests were added which exercise
+      partial parallel reads.
+
+      (JTH - 2018/07/16, HDFFV-10467)
+
+    - A bug was discovered in the parallel library which caused parallel
+      writes of filtered datasets to trigger an assertion failure in the
+      file free space manager.
+
+      This occurred when the filter used caused chunks to repeatedly shrink
+      and grow over the course of several dataset writes. The previous chunk
+      information, such as the size of the chunk and the offset in the file,
+      was being cached and not updated after each write, causing the next write
+      to the chunk to retrieve the incorrect cached information and run into
+      issues when reallocating space in the file for the chunk.
+
+      (JTH - 2018/07/16, HDFFV-10509)
+
+    - A bug was discovered in the parallel library which caused the
+      H5D__mpio_array_gatherv() function to allocate too much memory.
+
+      When the function is called with the 'allgather' parameter set
+      to a non-true value, the function will receive data from all MPI
+      ranks and gather it to the single rank specied by the 'root'
+      parameter. However, the bug in the function caused memory for
+      the received data to be allocated on all MPI ranks, not just the
+      singular rank specified as the receiver. In some circumstances,
+      this would cause an application to fail due to the large amounts
+      of memory being allocated.
+
+      (JTH - 2018/07/16, HDFFV-10467)
+
+    - Error checks in h5stat and when decoding messages
+
+      h5stat exited with seg fault/core dumped when
+      errors are encountered in the internal library.
+
+      Add error checks and --enable-error-stack option to h5stat.
+      Add range checks when decoding messages: old fill value, old
+      layout and refcount.
+
+      (VC - 2018/07/11, HDFFV-10333)
+
+    - If an HDF5 file contains a malformed compound datatype with a
+      suitably large offset, the type conversion code can run off
+      the end of the type conversion buffer, causing a segmentation
+      fault.
+
+      This issue was reported to The HDF Group as issue #CVE-2017-17507.
+
+      NOTE: The HDF5 C library cannot produce such a file. This condition
+            should only occur in a corrupt (or deliberately altered) file
+            or a file created by third-party software.
+
+      THE HDF GROUP WILL NOT FIX THIS BUG AT THIS TIME
+
+      Fixing this problem would involve updating the publicly visible
+      H5T_conv_t function pointer typedef and versioning the API calls
+      which use it. We normally only modify the public API during
+      major releases, so this bug will not be fixed at this time.
+
+      (DER - 2018/02/26, HDFFV-10356)
+
+
+    Configuration
+    -------------
+    - Applied patches to address Cywin build issues
+
+      There were three issues for Cygwin builds:
+      - Shared libs were not built.
+      - The -std=c99 flag caused a SIG_SETMASK undeclared error.
+      - Undefined errors when buildbing test shared libraries.
+
+      Patches to address these issues were received and incorporated in this version.
+
+      (LRK - 2018/07/18, HDFFV-10475)
+
+    - The --enable-debug/production configure flags are listed as 'deprecated'
+      when they should really be listed as 'removed'.
+
+      In the autotools overhaul several years ago, we removed these flags and
+      implemented a new --enable-build-mode= flag. This was done because we
+      changed the semantics of the modes and didn't want users to silently
+      be exposed to them. The newer system is also more flexible and us to
+      add other modes (like 'clean').
+
+      The --enable-debug/production flags are now listed as removed.
+
+      (DER - 2018/05/31, HDFFV-10505)
+
+    - Moved the location of gcc attribute.
+
+      The gcc attribute(no_sanitize), named as the macro HDF_NO_UBSAN,
+      was located after the function name. Builds with GCC 7 did not
+      indicate any problem, but GCC 8 issued errors. Moved the
+      attribute before the function name, as required.
+
+      (ADB - 2018/05/22, HDFFV-10473)
+
+    - Reworked java test suite into individual JUnit tests.
+
+      Testing the whole suite of java unit tests in a single JUnit run
+      made it difficult to determine actual failures when tests would fail.
+      Running each file set of tests individually, allows individual failures
+      to be diagnosed easier. A side benefit is that tests for optional components
+      of the library can be disabled if not configured.
+
+      (ADB - 2018/05/16, HDFFV-9739)
+
+    - Converted CMake global commands ADD_DEFINITIONS and INCLUDE_DIRECTORIES
+      to use target_* type commands. This change modernizes the CMake usage
+      in the HDF5 library.
+
+      In addition, there is the intention to convert to generator expressions,
+      where possible. The exception is Fortran FLAGS on Windows Visual Studio.
+      The HDF macros TARGET_C_PROPERTIES and TARGET_FORTRAN_PROPERTIES have
+      been removed with this change in usage.
+
+      The additional language (C++ and Fortran) checks have also been localized
+      to only be checked when that language is enabled.
+
+      (ADB - 2018/05/08)
+
+
+    Performance
+    -------------
+    - Revamped internal use of DXPLs, improving performance
+
+      (QAK - 2018/05/20)
+
+
+    Fortran
+    --------
+    - Fixed issue with h5fget_obj_count_f and using a file id of H5F_OBJ_ALL_F not
+      returning the correct count.
+
+      (MSB - 2018/5/15, HDFFV-10405)
+
+
+    C++ APIs
+    --------
+    - Adding default arguments to existing functions
+
+      Added the following items:
+      + Two more property list arguments are added to H5Location::createDataSet:
+        const DSetAccPropList& dapl = DSetAccPropList::DEFAULT
+        const LinkCreatPropList& lcpl = LinkCreatPropList::DEFAULT
+
+      + One more property list argument is added to H5Location::openDataSet:
+        const DSetAccPropList& dapl = DSetAccPropList::DEFAULT
+
+      (BMR - 2018/07/21, PR# 1146)
+
+    - Improvement C++ documentation
+
+      Replaced the table in main page of the C++ documentation from mht to htm format
+      for portability.
+
+      (BMR - 2018/07/17, PR# 1141)
+
+
+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, Version 5.2.0
+                                  Intel(R) C (icc), C++ (icpc), Fortran (icc)
+                                  compilers:
+                                     Version 17.0.0.098 Build 20160721
+                                  MPICH 3.1.4 compiled with GCC 4.9.3
+
+    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 7                     Visual Studio 2015 w/ Intel Fortran 16 (cmake)
+
+    Windows 7 x64                 Visual Studio 2012 w/ Intel Fortran 15 (cmake)
+                                  Visual Studio 2013 w/ Intel Fortran 15 (cmake)
+                                  Visual Studio 2015 w/ Intel Fortran 16 (cmake)
+                                  Visual Studio 2015 w/ Intel C, Fortran 2017 (cmake)
+                                  Visual Studio 2015 w/ MSMPI 8 (cmake)
+
+    Windows 10                    Visual Studio 2015 w/ Intel Fortran 18 (cmake)
+
+    Windows 10 x64                Visual Studio 2015 w/ Intel Fortran 18 (cmake)
+                                  Visual Studio 2017 w/ Intel Fortran 18 (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 Sierra 10.12.6         Apple LLVM version 8.1.0 (clang/clang++-802.0.42)
+    64-bit                        gfortran GNU Fortran (GCC) 7.1.0
+    (swallow/kite)                Intel icc/icpc/ifort version 17.0.2
+
+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
+Solaris2.11 32-bit                      n        y/y    n        y    y     y
+Solaris2.11 64-bit                      n        y/n    n        y    y     y
+Windows 7                               y        y/y    n        y    y     y
+Windows 7 x64                           y        y/y    y        y    y     y
+Windows 7 Cygwin                        n        y/n    n        y    y     y
+Windows 7 x64 Cygwin                    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 Mavericks 10.9.5 64-bit        n        y/y    n        y    y     y
+Mac OS X Yosemite 10.10.5 64-bit        n        y/y    n        y    y     y
+Mac OS X El Capitan 10.11.6 64-bit      n        y/y    n        y    y     y
+Mac OS Sierra 10.12.6 64-bit            n        y/y    n        y    y     y
+CentOS 7.2 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/y    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 7                                  y       y         y         y
+Windows 7 x64                              y       y         y         y
+Windows 7 Cygwin                           n       n         n         y
+Windows 7 x64 Cygwin                       n       n         n         y
+Windows 10                                 y       y         y         y
+Windows 10 x64                             y       y         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
+Mac OS Sierra 10.12.6 64-bit               y       n         y         y
+CentOS 7.2 Linux 2.6.32 x86_64 PGI         y       y         y         n
+CentOS 7.2 Linux 2.6.32 x86_64 GNU         y       y         y         y
+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,
+                                     3.1.0-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)
+
+    Linux 3.10.0-327.10.1.el7     MPICH 3.2 compiled with GCC 5.3.0
+    #1 SMP x86_64 GNU/Linux
+    (moohan)
+
+    Linux 2.6.32-573.18.1.el6.ppc64  MPICH mpich 3.1.4 compiled with
+    #1 SMP ppc64 GNU/Linux           IBM XL C/C++ for Linux, V13.1
+    (ostrich)                        and IBM XL Fortran for Linux, V15.1
+
+    Debian 8.4 3.16.0-4-amd64 #1 SMP Debian 3.16.36-1 x86_64 GNU/Linux
+                                  gcc, g++ (Debian 4.9.2-10) 4.9.2
+                                  GNU Fortran (Debian 4.9.2-10) 4.9.2
+                                  (cmake and autotools)
+
+    Fedora 24  4.7.2-201.fc24.x86_64 #1 SMP x86_64 x86_64 x86_64 GNU/Linux
+                                  gcc, g++ (GCC) 6.1.1 20160621
+                                      (Red Hat 6.1.1-3)
+                                  GNU Fortran (GCC) 6.1.1 20160621
+                                      (Red Hat 6.1.1-3)
+                                  (cmake and autotools)
+
+    Ubuntu 16.04.1 4.4.0-38-generic #57-Ubuntu SMP x86_64 GNU/Linux
+                                  gcc, g++ (Ubuntu 5.4.0-6ubuntu1~16.04.2)
+                                      5.4.0 20160609
+                                  GNU Fortran (Ubuntu 5.4.0-6ubuntu1~16.04.2)
+                                      5.4.0 20160609
+                                  (cmake and autotools)
+
+
+Known Problems
+==============
+
+    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.
+
+    Three tests fail with OpenMPI 3.0.0/GCC-7.2.0-2.29:
+        testphdf5 (ecdsetw, selnone, cchunk1, cchunk3, cchunk4, and actualio)
+        t_shapesame (sscontig2)
+        t_pflush1/fails on exit
+    The first two tests fail attempting collective writes.
+
+    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.
+
+
 %%%%1.10.2%%%%
 
 HDF5 version 1.10.2 released on 2018-03-29
diff --git a/release_docs/README_HDF5_CMake b/release_docs/README_HDF5_CMake
new file mode 100644
index 0000000..a2e7dce
--- /dev/null
+++ b/release_docs/README_HDF5_CMake
@@ -0,0 +1,23 @@
+This tar file contains 
+
+    build-unix.sh       script to build HDF5 with CMake on unix machines
+    build-unix-hpc.sh   script to build HDF5 with CMake on unix machines and run
+                        tests with batch scripts (sbatch).
+    CTestScript.cmake   
+    HDF5config.cmake    CMake scripts for building HDF5
+    HDF5options.cmake
+    hdf5-1.11.4         HDF5 1.11.4 source
+    SZip.tar.gz         source for building SZIP
+    ZLib.tar.gz         source for building ZLIB
+
+For more information about building HDF5 with CMake, see USING_HDF5_CMake.txt in
+hdf5-1.11.4/release_docs, or 
+https://portal.hdfgroup.org/display/support/Building+HDF5+with+CMake.
+
+For more information about building HDF5 with CMake on HPC machines, including 
+cross compiling on Cray XC40, see README_HPC in hdf5-1.11.4/release_docs.
+
+
+
+
+
diff --git a/release_docs/README_HPC b/release_docs/README_HPC
index bdeab67..67a5d6c 100644
--- a/release_docs/README_HPC
+++ b/release_docs/README_HPC
@@ -1,79 +1,206 @@
-HDF5 version 1.11.4 currently under development
-
-HDF5 source tar files with the HPC prefix are intended for use on clusters where 
-configuration and build steps will be done on a login node and executable and
-lib files that are built will be run on compute nodes.  
-
-Note these differences from the regular CMake tar and zip files:
-  - Test programs produced by this tar file will be run using batch scripts. 
-  - Serial and parallel HDF5options.cmake files, using parallel options by default.
-
-Note also that options are now available in HDF5 source to facilitate use of 
-toolchain files for using cross compilers available on login nodes to compile
-HDF5 for compute nodes.
-
-Instructions to configure build and test HDF5 using CMake:
-
-1. The cmake version must be 3.10 or later (cmake --version).
-2. Load or switch modules and set CC, FC, CXX for compilers desired.
-3. run build-unix.sh to configure, build, test and package HDF5 with CMake.
-
-Contents:
-
-build-unix.sh           Simple script for running CMake to configure, build, 
-                        test, and package HDF5.
-CTestScript.cmake       CMake script to configure, build, test and package 
-                        HDF5.
-hdf5-<version>          HDF5 source for <version>.
-HDF5config.cmake        CMake script to configure, build, test and package
-                        HDF5. 
-HDF5Examples            Source for HDF5 Examples.
-HDF5options.cmake       symlink to parallel or serial HDF5options.cmake files.
-                        Default is parallel file, which builds and tests both
-                        serial and parallel C and Fortran wrappers.
-                        To build serial only, C Fortran and C++ wrappers, delete
-                        The HDF5options.cmake link and run 
-                        'ln -s ser-HDF5options.cmake HDF5options.cmake' to switch.  
-par-HDF5options.cmake   Options file for HDF5 serial and parallel build and test.
-ser-HDF5options.cmake   Options file for HDF5 serial only build and test.
-SZip.tar.gz             Source for building SZip.
-ZLib.tar.gz             Source for buildng Zlib.
-
-
-To cross compile with this HPC-CMake tar.gz HDF5 source file:
-On Cray XC40  haswell login node for knl compute nodes using CMake and Cray modules:
-        1.  Uncomment line in HDF5options.txt to use a toolchain file - line 106 for
-            config/toolchain/crayle.cmake.
-        2.  Uncomment lines 110, 111, and 115 - 122 of HDF5options.cmake.
-            Line 110 allows configuring to complete on the haswell node.
-            Line 111 switches the compiler to build files for knl nodes.
-            Lines 115 - 122 set up test files to use sbatch to run build tests
-            in batch jobs on a knl compute node with 6 processes.
-        3.  Compiler module may be the default PrgEnv-intel/6.0.4 to use 
-            intel/18.0.2 or other intel, PrgEnv-cray/6.0.4 to use cce/8.7.4,
-            or PrgEnv-gnu/6.0.4 for GCC compilers.  PrgEnv-pgi/6.0.4 is also 
-            available but has not been tested with this tar file.
-        4.  These CMake options are set in config/toolchain/crayle.cmake:
-                set(CMAKE_SYSTEM_NAME Linux)
-                set(CMAKE_COMPILER_VENDOR "CrayLinuxEnvironment")
-                set(CMAKE_C_COMPILER cc)
-                set(CMAKE_CXX_COMPILER c++)
-                set(CMAKE_Fortran_COMPILER ftn)
-                set(CMAKE_CROSSCOMPILING_EMULATOR "")
-
-        5.  Settings for two other cross-compiling options are also in the 
-            config/toolchain files which do not seem to be necessary with the 
-            Cray PrgEnv-* modules
-            a.  HDF5_USE_PREGEN.  This option, along with the HDF5_USE_PREGEN_DIR
-                CMake variable would allow the use of an appropriate H5Tinit.c 
-                file with type information generated on a compute node to be used
-                when cross compiling for those compute nodes.  The use of the 
-                variables in lines 110 and 111 of HDF5options.cmake file seem to
-                preclude needing this option with the available Cray modules and
-                CMake options.
-            b.  HDF5_BATCH_H5DETECT and associated CMake variables.  This option
-                when properly configured will run H5detect in a batch job on a
-                compute node at the beginning of the CMake build process.  It 
-                was also found to be unnecessary with the available Cray modules
-                and CMake options.
--
+************************************************************************
+*    Using CMake to build and test HDF5 source on HPC machines         *
+************************************************************************ 
+
+                    Contents
+
+Section I:     Prerequisites
+Section II:    Obtain HDF5 source
+Section III:   Using ctest command to build and test
+Section IV:    Cross compiling
+Section V:     Manual alternatives
+Section VI:    Other cross compiling options
+
+************************************************************************
+
+========================================================================
+I. Prerequisites
+========================================================================
+    1. Create a working directory that is accessible from the compute nodes for 
+       running tests; the working directory should be in a scratch space or a
+       parallel file system space since testing will use this space.  Building
+       from HDF5 source in a 'home' directory typically results in test 
+       failures and should be avoided.
+	  
+    2. Load modules for desired compilers, module for cmake version 3.10 or greater, 
+       and set any needed environment variables for compilers (i.e., CC, FC, CXX).
+       Unload any problematic modules (i.e., craype-hugepages2M).
+
+========================================================================
+II. Obtain HDF5 source
+========================================================================
+Obtain HDF5 source code from the HDF5 repository using a git command or 
+from a release tar file in a working directory:
+
+    git clone https://git@bitbucket.hdfgroup.org/scm/hdffv/hdf5.git 
+        [-b branch] [source directory]
+
+If no branch is specified, then the 'develop' version will be checked out.
+If no source directory is specified, then the source will be located in the 
+'hdf5' directory. The Cmake scripts expect the source to be in a directory 
+named hdf5-<version string>, where 'version string' uses the format '1.xx.xx'.
+For example, for the current 'develop' version, the "hdf5" directory should 
+be renamed "hdf5-1.11.4", or for the first hdf5_1_10_5 pre-release version, 
+it should be renamed "hdf5-1.10.5-pre1".
+
+If the version number is not known a priori, the version string 
+can be obtained by running bin/h5vers in the top level directory of the source clone, and
+the source directory renamed 'hdf5-<version string>'.
+
+Release or snapshot tar files may also be extracted and used.
+
+========================================================================
+III. Using ctest command to build and test
+========================================================================
+
+The ctest command [1]:
+
+  ctest -S HDF5config.cmake,BUILD_GENERATOR=Unix -C Release -V -O hdf5.log
+
+will configure, build, test and package HDF5 from the downloaded source 
+after the setup steps outlined below are followed.
+
+CMake option variables are available to allow running test programs in batch 
+scripts on compute nodes and to cross-compile for compute node hardware using 
+a cross-compiling emulator.  The setup steps will make default settings for
+parallel or serial only builds available to the CMake command.  
+
+    1. For the current 'develop' version the "hdf5" directory should be renamed 
+       "hdf5-1.11.4".
+
+    2. Three cmake script files need to be copied to the working directory, or
+       have symbolic links to them, created in the working directory:
+   
+       hdf5-1.11.4/config/cmake/scripts/HDF5config.cmake
+       hdf5-1.11.4/config/cmake/scripts/CTestScript.cmake
+       hdf5-1.11.4/config/cmake/scripts/HDF5options.cmake 
+
+       should be copied to the working directory.
+
+    3. The resulting contents of the working directory are then:
+
+       CTestScript.cmake
+       HDF5config.cmake
+       HDF5options.cmake
+       hdf5-1.11.4
+
+       Additionally, when the ctest command runs [1], it will add a build directory 
+       in the working directory.
+
+    4. The following options (among others) can be added to the ctest
+       command [1], following '-S HDF5config.cmake,' and separated by ',':
+
+       HPC=sbatch   (or 'bsub' or 'raybsub') indicates which type of batch
+                     files to use for running tests.  If omitted, test 
+                     will run on the local machine or login node.
+
+       KNL=true      to cross-compile for KNL compute nodes on CrayXC40
+                     (see section IV)
+
+       MPI=true      enables parallel, disables c++, java, and threadsafe
+
+       LOCAL_BATCH_SCRIPT_ARGS="--account=<account#>"  to supply user account
+                                                       information for batch jobs
+
+       The HPC options will add BUILD_GENERATOR=Unix for the three HPC options.
+       An example ctest command for a parallel build on a system using sbatch is
+   
+         ctest -S HDF5config.cmake,HPC=sbatch,MPI=true -C Release -V -O hdf5.log
+
+       Adding the option 'KNL=true' to the above list will compile for KNL nodes, 
+       for example, on 'mutrino' and other CrayXC40 machines.
+
+       Changing -V to -VV will produce more logging information in HDF5.log. 
+
+    More detailed CMake information can be found in the HDF5 source in 
+    release_docs/INSTALL_CMake.txt.
+
+========================================================================
+IV. Cross-compiling
+========================================================================
+For cross-compiling on Cray, set environment variables CC=cc, FC=ftn 
+and CXX=CC (for c++) after all compiler modules are loaded since switching
+compiler modules may unset or reset these variables.
+
+CMake provides options for cross-compiling.  To cross-compile for KNL hardware 
+on mutrino and other CrayXC40 machines, add HPC=sbatch,KNL=true to the 
+ctest command line.  This will set the following options from the 
+config/cmake/scripts/HPC/sbatch-HDF5options.cmake file:
+
+    set (COMPILENODE_HWCOMPILE_MODULE "craype-haswell")
+    set (COMPUTENODE_HWCOMPILE_MODULE "craype-mic-knl")
+    set (LOCAL_BATCH_SCRIPT_NAME "knl_ctestS.sl")
+    set (LOCAL_BATCH_SCRIPT_PARALLEL_NAME "knl_ctestP.sl")
+    set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DCMAKE_TOOLCHAIN_FILE:STRING=config/toolchain/crayle.cmake")
+
+On the Cray XC40 the craype-haswell module is needed for configuring, and the 
+craype-mic-knl module is needed for building to run on the KNL nodes. CMake
+with the above options will swap modules after configuring is complete, 
+but before compiling programs for KNL.
+
+The sbatch script arguments for running jobs on KNL nodes may differ on CrayXC40
+machines other than mutrino.  The batch scripts knl_ctestS.sl and knl_ctestP.sl 
+have the correct arguments for mutrino:  "#SBATCH -p knl -C quad,cache".  For 
+cori, another CrayXC40, that line is replaced by "#SBATCH -C knl,quad,cache".  
+For cori (and other machines), the values in LOCAL_BATCH_SCRIPT_NAME and 
+LOCAL_BATCH_SCRIPT_PARALLEL_NAME in the config/cmake/scripts/HPC/sbatch-HDF5options.cmake 
+file can be replaced by cori_knl_ctestS.sl and cori_knl_ctestS.sl, or the lines 
+can be edited in the batch files in hdf5-1.11.4/bin/batch.
+
+========================================================================
+V. Manual alternatives
+========================================================================
+If using ctest is undesirable, one can create a build directory and run the cmake 
+configure command, for example
+
+"/projects/Mutrino/hpcsoft/cle6.0/common/cmake/3.10.2/bin/cmake" 
+-C "<working directory>/hdf5-1.11.4/config/cmake/cacheinit.cmake" 
+-DCMAKE_BUILD_TYPE:STRING=Release -DHDF5_BUILD_FORTRAN:BOOL=ON 
+-DHDF5_BUILD_JAVA:BOOL=OFF 
+-DCMAKE_INSTALL_PREFIX:PATH=<working directory>/HDF_Group/HDF5/1.11.4 
+-DHDF5_ENABLE_Z_LIB_SUPPORT:BOOL=OFF -DHDF5_ENABLE_SZIP_SUPPORT:BOOL=OFF 
+-DHDF5_ENABLE_PARALLEL:BOOL=ON -DHDF5_BUILD_CPP_LIB:BOOL=OFF 
+-DHDF5_BUILD_JAVA:BOOL=OFF -DHDF5_ENABLE_THREADSAFE:BOOL=OFF 
+-DHDF5_PACKAGE_EXTLIBS:BOOL=ON -DLOCAL_BATCH_TEST:BOOL=ON 
+-DMPIEXEC_EXECUTABLE:STRING=srun -DMPIEXEC_NUMPROC_FLAG:STRING=-n 
+-DMPIEXEC_MAX_NUMPROCS:STRING=6 
+-DCMAKE_TOOLCHAIN_FILE:STRING=config/toolchain/crayle.cmake 
+-DLOCAL_BATCH_SCRIPT_NAME:STRING=knl_ctestS.sl 
+-DLOCAL_BATCH_SCRIPT_PARALLEL_NAME:STRING=knl_ctestP.sl -DSITE:STRING=mutrino 
+-DBUILDNAME:STRING=par-knl_GCC493-SHARED-Linux-4.4.156-94.61.1.16335.0.PTF.1107299-default-x86_64 
+"-GUnix Makefiles" "" "<working directory>/hdf5-1.11.4"
+
+followed by make and batch jobs to run tests.
+
+To cross-compile on CrayXC40, run the configure command with the craype-haswell 
+module loaded, then switch to the craype-mic-knl module for the build process.
+
+Tests on machines using slurm can be run with 
+
+"sbatch -p knl -C quad,cache ctestS.sl" 
+
+or 
+
+"sbatch -p knl -C quad,cache ctestP.sl" 
+
+for parallel builds.
+ 
+Tests on machines using LSF will typically use "bsub ctestS.lsf", etc.
+
+========================================================================
+VI.    Other cross compiling options
+========================================================================
+Settings for two other cross-compiling options are also in the config/toolchain 
+files which do not seem to be necessary with the Cray PrgEnv-* modules
+
+1.  HDF5_USE_PREGEN.  This option, along with the HDF5_USE_PREGEN_DIR CMake 
+    variable would allow the use of an appropriate H5Tinit.c file with type 
+	information generated on a compute node to be used when cross compiling 
+	for those compute nodes.  The use of the variables in lines 110 and 111 
+	of HDF5options.cmake file seem to preclude needing this option with the 
+	available Cray modules and CMake option.
+
+2.  HDF5_BATCH_H5DETECT and associated CMake variables.  This option when 
+    properly configured will run H5detect in a batch job on a compute node 
+	at the beginning of the CMake build process.  It was also found to be 
+	unnecessary with the available Cray modules and CMake options.
diff --git a/release_docs/RELEASE.txt b/release_docs/RELEASE.txt
index 3ba00f0..876fb63 100644
--- a/release_docs/RELEASE.txt
+++ b/release_docs/RELEASE.txt
@@ -236,6 +236,16 @@ Bug Fixes since HDF5-1.10.3 release
 
       (NAF - 2019/03/06, HDFFV-10716)
 
+    - Fixed memory leak in scale offset filter
+
+      In a special case where the MinBits is the same as the number of bits in
+      the datatype's precision, the filter's data buffer was not freed, causing 
+      the memory usage to grow. In general the buffer was freed correctly.  The
+      Minbits are the minimal number of bits to store the data values.  Please 
+      see the reference manual for H5Pset_scaleoffset for the detail.
+
+      (RL - 2019/3/4, HDFFV-10705) 
+
     - Fix hangs with collective metadata reads during chunked dataset I/O
 
       In the parallel library, it was discovered that when a particular
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 83240bd..5f7bd48 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -1120,7 +1120,7 @@ target_link_libraries (${HDF5_LIB_TARGET}
 )
 if (NOT WIN32)
   target_link_libraries (${HDF5_LIB_TARGET}
-    PUBLIC $<$<BOOL:${HDF5_ENABLE_THREADSAFE}>:Threads::Threads>
+    PRIVATE $<$<BOOL:${HDF5_ENABLE_THREADSAFE}>:Threads::Threads>
   )
 endif ()
 set_global_variable (HDF5_LIBRARIES_TO_EXPORT ${HDF5_LIB_TARGET})
@@ -1152,8 +1152,8 @@ if (BUILD_SHARED_LIBS)
   )
   TARGET_C_PROPERTIES (${HDF5_LIBSH_TARGET} SHARED)
   target_link_libraries (${HDF5_LIBSH_TARGET}
-      PRIVATE ${LINK_LIBS} ${LINK_COMP_LIBS} "$<$<BOOL:${HDF5_ENABLE_PARALLEL}>:${MPI_C_LIBRARIES}>"
-      PUBLIC $<$<NOT:$<PLATFORM_ID:Windows>>:${CMAKE_DL_LIBS}> $<$<BOOL:${HDF5_ENABLE_THREADSAFE}>:Threads::Threads>
+      PRIVATE ${LINK_LIBS} ${LINK_COMP_LIBS} "$<$<BOOL:${HDF5_ENABLE_PARALLEL}>:${MPI_C_LIBRARIES}>" $<$<BOOL:${HDF5_ENABLE_THREADSAFE}>:Threads::Threads>
+      PUBLIC $<$<NOT:$<PLATFORM_ID:Windows>>:${CMAKE_DL_LIBS}>
   )
   set_global_variable (HDF5_LIBRARIES_TO_EXPORT "${HDF5_LIBRARIES_TO_EXPORT};${HDF5_LIBSH_TARGET}")
   H5_SET_LIB_OPTIONS (${HDF5_LIBSH_TARGET} ${HDF5_LIB_NAME} SHARED "LIB")
diff --git a/src/H5CX.c b/src/H5CX.c
index c97bdcd..b56d66d 100644
--- a/src/H5CX.c
+++ b/src/H5CX.c
@@ -64,17 +64,22 @@
 #define H5CX_get_my_context() (&H5CX_head_g)
 #endif /* H5_HAVE_THREADSAFE */
 
+/* Common macro for the retrieving the pointer to a property list */
+#define H5CX_RETRIEVE_PLIST(PL, FAILVAL)                                      \
+    /* Check if the property list is already available */                     \
+    if(NULL == (*head)->ctx.PL)                                               \
+        /* Get the property list pointer */                                   \
+        if(NULL == ((*head)->ctx.PL = (H5P_genplist_t *)H5I_object((*head)->ctx.H5_GLUE(PL,_id)))) \
+            HGOTO_ERROR(H5E_CONTEXT, H5E_BADTYPE, (FAILVAL), "can't get property list")
+
 /* Common macro for the duplicated code to retrieve properties from a property list */
 #define H5CX_RETRIEVE_PROP_COMMON(PL, DEF_PL, PROP_NAME, PROP_FIELD)          \
     /* Check for default property list */                                     \
     if((*head)->ctx.H5_GLUE(PL,_id) == (DEF_PL))                              \
         HDmemcpy(&(*head)->ctx.PROP_FIELD, &H5_GLUE3(H5CX_def_,PL,_cache).PROP_FIELD, sizeof(H5_GLUE3(H5CX_def_,PL,_cache).PROP_FIELD)); \
     else {                                                                    \
-        /* Check if the property list is already available */                 \
-        if(NULL == (*head)->ctx.PL)                                           \
-            /* Get the dataset transfer property list pointer */              \
-            if(NULL == ((*head)->ctx.PL = (H5P_genplist_t *)H5I_object((*head)->ctx.H5_GLUE(PL,_id)))) \
-                HGOTO_ERROR(H5E_CONTEXT, H5E_BADTYPE, FAIL, "can't get default dataset transfer property list") \
+        /* Retrieve the property list */                                      \
+        H5CX_RETRIEVE_PLIST(PL, FAIL)                                         \
                                                                               \
         /* Get the property */                                                \
         if(H5P_get((*head)->ctx.PL, (PROP_NAME), &(*head)->ctx.PROP_FIELD) < 0) \
@@ -108,11 +113,8 @@
                                                                               \
     /* Check if property exists in DXPL */                                    \
     if(!(*head)->ctx.H5_GLUE(PROP_FIELD,_set)) {                              \
-        /* Check if the property list is already available */                 \
-        if(NULL == (*head)->ctx.dxpl)                                         \
-            /* Get the dataset transfer property list pointer */              \
-            if(NULL == ((*head)->ctx.dxpl = (H5P_genplist_t *)H5I_object((*head)->ctx.dxpl_id))) \
-                HGOTO_ERROR(H5E_CONTEXT, H5E_BADTYPE, FAIL, "can't get default dataset transfer property list") \
+        /* Retrieve the dataset transfer property list */                     \
+        H5CX_RETRIEVE_PLIST(dxpl, FAIL)                                       \
                                                                               \
         if((check_prop = H5P_exist_plist((*head)->ctx.dxpl, PROP_NAME)) < 0)  \
             HGOTO_ERROR(H5E_CONTEXT, H5E_CANTGET, FAIL, "error checking for property") \
@@ -129,15 +131,12 @@
 /* Macro for the duplicated code to test and set properties for a property list */
 #define H5CX_SET_PROP(PROP_NAME, PROP_FIELD)                                  \
     if((*head)->ctx.H5_GLUE(PROP_FIELD,_set)) {                               \
-        /* Check if the property list is already available */                 \
-        if(NULL == (*head)->ctx.dxpl)                                         \
-            /* Get the dataset transfer property list pointer */              \
-            if(NULL == ((*head)->ctx.dxpl = (H5P_genplist_t *)H5I_object((*head)->ctx.dxpl_id))) \
-                HGOTO_ERROR(H5E_CONTEXT, H5E_BADTYPE, NULL, "can't get default dataset transfer property list") \
+        /* Retrieve the dataset transfer property list */                     \
+        H5CX_RETRIEVE_PLIST(dxpl, NULL)                                       \
                                                                               \
-        /* Set the chunk filter mask property */                              \
+        /* Set the property */                              		      \
         if(H5P_set((*head)->ctx.dxpl, PROP_NAME, &(*head)->ctx.PROP_FIELD) < 0) \
-            HGOTO_ERROR(H5E_CONTEXT, H5E_CANTSET, NULL, "error setting filter mask xfer property") \
+            HGOTO_ERROR(H5E_CONTEXT, H5E_CANTSET, NULL, "error setting data xfer property") \
     } /* end if */
 #endif /* H5_HAVE_PARALLEL */
 
@@ -175,7 +174,7 @@
  *      corresponding property in the property list to be set when the API
  *      context is popped, when returning from the API routine.  Note that the
  *      naming of these fields, <foo> and <foo>_set, is important for the
-*       H5CX_TEST_SET_PROP and H5CX_SET_PROP macros to work properly.
+ *      H5CX_TEST_SET_PROP and H5CX_SET_PROP macros to work properly.
  */
 typedef struct H5CX_t {
     /* DXPL */
@@ -378,6 +377,9 @@ static H5CX_dcpl_cache_t H5CX_def_dcpl_cache;
 /* Declare a static free list to manage H5CX_node_t structs */
 H5FL_DEFINE_STATIC(H5CX_node_t);
 
+/* Declare a static free list to manage H5CX_state_t structs */
+H5FL_DEFINE_STATIC(H5CX_state_t);
+
 
 
 /*--------------------------------------------------------------------------
@@ -709,6 +711,226 @@ H5CX_push_special(void)
 
 
 /*-------------------------------------------------------------------------
+ * Function:    H5CX_retrieve_state
+ *
+ * Purpose:     Retrieve the state of an API context, for later resumption.
+ *
+ * Note:	This routine _only_ tracks the state of API context information
+ *		set before the VOL callback is invoked, not values that are
+ *		set internal to the library.  It's main purpose is to provide
+ *		API context state to VOL connectors.
+ *
+ * Return:      Non-negative on success / Negative on failure
+ *
+ * Programmer:  Quincey Koziol
+ *              January 8, 2019
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5CX_retrieve_state(H5CX_state_t **api_state)
+{
+    H5CX_node_t **head = H5CX_get_my_context();  /* Get the pointer to the head of the API context, for this thread */
+    herr_t ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_NOAPI(FAIL)
+
+    /* Sanity check */
+    HDassert(head && *head);
+    HDassert(api_state);
+
+    /* Allocate & clear API context state */
+    if(NULL == (*api_state = H5FL_CALLOC(H5CX_state_t)))
+        HGOTO_ERROR(H5E_CONTEXT, H5E_CANTALLOC, FAIL, "unable to allocate new API context state")
+
+    /* Check for non-default DXPL */
+    if(H5P_DATASET_XFER_DEFAULT != (*head)->ctx.dxpl_id) {
+        /* Retrieve the DXPL property list */
+        H5CX_RETRIEVE_PLIST(dxpl, FAIL)
+
+        /* Copy the DXPL ID */
+        if(((*api_state)->dxpl_id = H5P_copy_plist((H5P_genplist_t *)(*head)->ctx.dxpl, FALSE)) < 0)
+            HGOTO_ERROR(H5E_CONTEXT, H5E_CANTCOPY, FAIL, "can't copy property list")
+    } /* end if */
+    else
+        (*api_state)->dxpl_id = H5P_DATASET_XFER_DEFAULT;
+
+    /* Check for non-default LAPL */
+    if(H5P_LINK_ACCESS_DEFAULT != (*head)->ctx.lapl_id) {
+        /* Retrieve the LAPL property list */
+        H5CX_RETRIEVE_PLIST(lapl, FAIL)
+
+        /* Copy the LAPL ID */
+        if(((*api_state)->lapl_id = H5P_copy_plist((H5P_genplist_t *)(*head)->ctx.lapl, FALSE)) < 0)
+            HGOTO_ERROR(H5E_CONTEXT, H5E_CANTCOPY, FAIL, "can't copy property list")
+    } /* end if */
+    else
+        (*api_state)->lapl_id = H5P_LINK_ACCESS_DEFAULT;
+
+    /* Keep a reference to the current VOL wrapping context */
+    (*api_state)->vol_wrap_ctx = (*head)->ctx.vol_wrap_ctx;
+    if(NULL != (*api_state)->vol_wrap_ctx)
+        if(H5VL_inc_vol_wrapper((*api_state)->vol_wrap_ctx) < 0)
+            HGOTO_ERROR(H5E_CONTEXT, H5E_CANTINC, FAIL, "can't increment refcount on VOL wrapping context")
+
+    /* Keep a copy of the VOL connector property, if there is one */
+    if((*head)->ctx.vol_connector_prop_valid && (*head)->ctx.vol_connector_prop.connector_id > 0) {
+        /* Get the connector property */
+        HDmemcpy(&(*api_state)->vol_connector_prop, &(*head)->ctx.vol_connector_prop, sizeof(H5VL_connector_prop_t));
+
+        /* Check for actual VOL connector property */
+        if((*api_state)->vol_connector_prop.connector_id) {
+            /* Copy connector info, if it exists */
+            if((*api_state)->vol_connector_prop.connector_info) {
+                H5VL_class_t *connector;           /* Pointer to connector */
+                void *new_connector_info = NULL;    /* Copy of connector info */
+
+                /* Retrieve the connector for the ID */
+                if(NULL == (connector = (H5VL_class_t *)H5I_object((*api_state)->vol_connector_prop.connector_id)))
+                    HGOTO_ERROR(H5E_CONTEXT, H5E_BADTYPE, FAIL, "not a VOL connector ID")
+
+                /* Allocate and copy connector info */
+                if(H5VL_copy_connector_info(connector, &new_connector_info, (*api_state)->vol_connector_prop.connector_info) < 0)
+                    HGOTO_ERROR(H5E_CONTEXT, H5E_CANTCOPY, FAIL, "connector info copy failed")
+                (*api_state)->vol_connector_prop.connector_info = new_connector_info;
+            } /* end if */
+
+            /* Increment the refcount on the connector ID */
+            if(H5I_inc_ref((*api_state)->vol_connector_prop.connector_id, FALSE) < 0)
+                HGOTO_ERROR(H5E_CONTEXT, H5E_CANTINC, FAIL, "incrementing VOL connector ID failed")
+        } /* end if */
+    } /* end if */
+
+#ifdef H5_HAVE_PARALLEL
+    /* Save parallel I/O settings */
+    (*api_state)->coll_metadata_read = (*head)->ctx.coll_metadata_read;
+#endif /* H5_HAVE_PARALLEL */
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5CX_retrieve_state() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5CX_restore_state
+ *
+ * Purpose:     Restore an API context, from a previously retrieved state.
+ *
+ * Note:	This routine _only_ resets the state of API context information
+ *		set before the VOL callback is invoked, not values that are
+ *		set internal to the library.  It's main purpose is to restore
+ *		API context state from VOL connectors.
+ *
+ * Return:      Non-negative on success / Negative on failure
+ *
+ * Programmer:  Quincey Koziol
+ *              January 9, 2019
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5CX_restore_state(const H5CX_state_t *api_state)
+{
+    H5CX_node_t **head = H5CX_get_my_context();  /* Get the pointer to the head of the API context, for this thread */
+
+    FUNC_ENTER_NOAPI_NOINIT_NOERR
+
+    /* Sanity check */
+    HDassert(head && *head);
+    HDassert(api_state);
+
+    /* Restore the DXPL info */
+    (*head)->ctx.dxpl_id = api_state->dxpl_id;
+    (*head)->ctx.dxpl = NULL;
+
+    /* Restore the LAPL info */
+    (*head)->ctx.lapl_id = api_state->lapl_id;
+    (*head)->ctx.lapl = NULL;
+
+    /* Restore the VOL wrapper context */
+    (*head)->ctx.vol_wrap_ctx = api_state->vol_wrap_ctx;
+
+    /* Restore the VOL connector info */
+    if(api_state->vol_connector_prop.connector_id) {
+        HDmemcpy(&(*head)->ctx.vol_connector_prop, &api_state->vol_connector_prop, sizeof(H5VL_connector_prop_t));
+        (*head)->ctx.vol_connector_prop_valid = TRUE;
+    } /* end if */
+
+#ifdef H5_HAVE_PARALLEL
+    /* Restore parallel I/O settings */
+    (*head)->ctx.coll_metadata_read = api_state->coll_metadata_read;
+#endif /* H5_HAVE_PARALLEL */
+
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* end H5CX_restore_state() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5CX_free_state
+ *
+ * Purpose:     Free a previously retrievedAPI context state
+ *
+ * Return:      Non-negative on success / Negative on failure
+ *
+ * Programmer:  Quincey Koziol
+ *              January 9, 2019
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5CX_free_state(H5CX_state_t *api_state)
+{
+    herr_t ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_NOAPI(FAIL)
+
+    /* Sanity check */
+    HDassert(api_state);
+
+    /* Release the DXPL */
+    if(api_state->dxpl_id != H5P_DATASET_XFER_DEFAULT)
+        if(H5I_dec_ref(api_state->dxpl_id) < 0)
+            HGOTO_ERROR(H5E_CONTEXT, H5E_CANTDEC, FAIL, "can't decrement refcount on DXPL")
+
+    /* Release the LAPL */
+    if(api_state->lapl_id != H5P_LINK_ACCESS_DEFAULT)
+        if(H5I_dec_ref(api_state->lapl_id) < 0)
+            HGOTO_ERROR(H5E_CONTEXT, H5E_CANTDEC, FAIL, "can't decrement refcount on LAPL")
+
+    /* Release the VOL wrapper context */
+    if(api_state->vol_wrap_ctx)
+        if(H5VL_dec_vol_wrapper(api_state->vol_wrap_ctx) < 0)
+            HGOTO_ERROR(H5E_CONTEXT, H5E_CANTDEC, FAIL, "can't decrement refcount on VOL wrapping context")
+
+    /* Release the VOL connector property, if it was set */
+    if(api_state->vol_connector_prop.connector_id) {
+        /* Clean up any VOL connector info */
+        if(api_state->vol_connector_prop.connector_info) {
+            H5VL_class_t *connector;       /* Pointer to connector */
+
+            /* Retrieve the connector for the ID */
+            if(NULL == (connector = (H5VL_class_t *)H5I_object(api_state->vol_connector_prop.connector_id)))
+                HGOTO_ERROR(H5E_CONTEXT, H5E_BADTYPE, FAIL, "not a VOL connector ID")
+
+            /* Free the connector info */
+            if(H5VL_free_connector_info(connector, api_state->vol_connector_prop.connector_info) < 0)
+                HGOTO_ERROR(H5E_CONTEXT, H5E_CANTRELEASE, FAIL, "unable to release VOL connector info object")
+        } /* end if */
+
+        /* Decrement connector ID */
+        if(H5I_dec_ref(api_state->vol_connector_prop.connector_id) < 0)
+            HDONE_ERROR(H5E_CONTEXT, H5E_CANTDEC, FAIL, "can't close VOL connector ID")
+    } /* end if */
+
+    /* Free the state */
+    api_state = H5FL_FREE(H5CX_state_t, api_state);
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5CX_free_state() */
+
+
+/*-------------------------------------------------------------------------
  * Function:    H5CX_is_def_dxpl
  *
  * Purpose:     Checks if the API context is using the library's default DXPL
@@ -951,6 +1173,7 @@ H5CX_set_loc(hid_t
 #endif /* H5_HAVE_PARALLEL */
    loc_id)
 {
+#ifdef H5_HAVE_PARALLEL
     H5CX_node_t **head = H5CX_get_my_context();  /* Get the pointer to the head of the API context, for this thread */
     herr_t ret_value = SUCCEED;         /* Return value */
 
@@ -959,7 +1182,6 @@ H5CX_set_loc(hid_t
     /* Sanity check */
     HDassert(head && *head);
 
-#ifdef H5_HAVE_PARALLEL
     /* Set collective metadata read flag */
     (*head)->ctx.coll_metadata_read = TRUE;
 
@@ -980,10 +1202,14 @@ H5CX_set_loc(hid_t
         if(mpi_comm != MPI_COMM_NULL)
             MPI_Barrier(mpi_comm);
     } /* end if */
-#endif /* H5_HAVE_PARALLEL */
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
+#else /* H5_HAVE_PARALLEL */
+    FUNC_ENTER_NOAPI_NOINIT_NOERR
+
+    FUNC_LEAVE_NOAPI(SUCCEED)
+#endif /* H5_HAVE_PARALLEL */
 } /* end H5CX_set_loc() */
 
 
diff --git a/src/H5CXprivate.h b/src/H5CXprivate.h
index 51ee96b..80f1ac4 100644
--- a/src/H5CXprivate.h
+++ b/src/H5CXprivate.h
@@ -39,6 +39,19 @@
 /* Library Private Typedefs */
 /****************************/
 
+/* API context state */
+typedef struct H5CX_state_t {
+    hid_t dxpl_id;              /* DXPL for operation */
+    hid_t lapl_id;              /* LAPL for operation */
+    void *vol_wrap_ctx;         /* VOL connector's "wrap context" for creating IDs */
+    H5VL_connector_prop_t vol_connector_prop;   /* VOL connector property */
+
+#ifdef H5_HAVE_PARALLEL
+    /* Internal: Parallel I/O settings */
+    hbool_t coll_metadata_read; /* Whether to use collective I/O for metadata read */
+#endif /* H5_HAVE_PARALLEL */
+} H5CX_state_t;
+
 
 /*****************************/
 /* Library-private Variables */
@@ -57,6 +70,11 @@ H5_DLL herr_t H5CX_pop(void);
 H5_DLL void H5CX_push_special(void);
 H5_DLL hbool_t H5CX_is_def_dxpl(void);
 
+/* API context state routines */
+H5_DLL herr_t H5CX_retrieve_state(H5CX_state_t **api_state);
+H5_DLL herr_t H5CX_restore_state(const H5CX_state_t *api_state);
+H5_DLL herr_t H5CX_free_state(H5CX_state_t *api_state);
+
 /* "Setter" routines for API context info */
 H5_DLL void H5CX_set_dxpl(hid_t dxpl_id);
 H5_DLL void H5CX_set_lapl(hid_t lapl_id);
diff --git a/src/H5VL.c b/src/H5VL.c
index aa276ec..334de88 100644
--- a/src/H5VL.c
+++ b/src/H5VL.c
@@ -488,6 +488,9 @@ done:
  *
  * Purpose:     Compares two connector classes (based on their value field)
  *
+ * Note:	This routine is _only_ for HDF5 VOL connector authors!  It is
+ *		_not_ part of the public API for HDF5 application developers.
+ *
  * Return:      Success:    Non-negative, *cmp set to a value like strcmp
  *
  *              Failure:    Negative, *cmp unset
@@ -587,3 +590,159 @@ done:
     FUNC_LEAVE_API(ret_value)
 } /* H5VLobject() */
 
+
+/*---------------------------------------------------------------------------
+ * Function:    H5VLretrieve_lib_state
+ *
+ * Purpose:     Retrieves a copy of the internal state of the HDF5 library,
+ *		so that it can be restored later.
+ *
+ * Note:	This routine is _only_ for HDF5 VOL connector authors!  It is
+ *		_not_ part of the public API for HDF5 application developers.
+ *
+ * Return:      Success:    Non-negative, *state set
+ *              Failure:    Negative, *state unset
+ *
+ * Programmer:	Quincey Koziol
+ *		Thursday, January 10, 2019
+ *
+ *---------------------------------------------------------------------------
+ */
+herr_t
+H5VLretrieve_lib_state(void **state)
+{
+    herr_t ret_value = SUCCEED; /* Return value */
+
+    /* Must use this, to avoid modifying the API context stack in FUNC_ENTER */
+    FUNC_ENTER_API_NOINIT
+    H5TRACE1("e", "**x", state);
+
+    /* Check args */
+    if(NULL == state)
+        HGOTO_ERROR(H5E_VOL, H5E_BADVALUE, FAIL, "invalid state pointer")
+
+    /* Retrieve the library state */
+    if(H5VL_retrieve_lib_state(state) < 0)
+        HGOTO_ERROR(H5E_VOL, H5E_CANTGET, FAIL, "can't retrieve library state")
+
+done:
+    FUNC_LEAVE_API_NOINIT(ret_value)
+} /* H5VLretrieve_lib_state() */
+
+
+/*---------------------------------------------------------------------------
+ * Function:    H5VLrestore_lib_state
+ *
+ * Purpose:     Restores the internal state of the HDF5 library.
+ *
+ * Note:	This routine is _only_ for HDF5 VOL connector authors!  It is
+ *		_not_ part of the public API for HDF5 application developers.
+ *
+ * Return:      Success:    Non-negative
+ *              Failure:    Negative
+ *
+ * Programmer:	Quincey Koziol
+ *		Thursday, January 10, 2019
+ *
+ *---------------------------------------------------------------------------
+ */
+herr_t
+H5VLrestore_lib_state(const void *state)
+{
+    herr_t ret_value = SUCCEED; /* Return value */
+
+    /* Must use this, to avoid modifying the API context stack in FUNC_ENTER */
+    FUNC_ENTER_API_NOINIT
+    H5TRACE1("e", "*x", state);
+
+    /* Check args */
+    if(NULL == state)
+        HGOTO_ERROR(H5E_VOL, H5E_BADVALUE, FAIL, "invalid state pointer")
+
+    /* Restore the library state */
+    if(H5VL_restore_lib_state(state) < 0)
+        HGOTO_ERROR(H5E_VOL, H5E_CANTSET, FAIL, "can't restore library state")
+
+done:
+    FUNC_LEAVE_API_NOINIT(ret_value)
+} /* H5VLrestore_lib_state() */
+
+
+/*---------------------------------------------------------------------------
+ * Function:    H5VLreset_lib_state
+ *
+ * Purpose:     Resets the internal state of the HDF5 library, undoing the
+ *		affects of H5VLrestore_lib_state.
+ *
+ * Note:	This routine is _only_ for HDF5 VOL connector authors!  It is
+ *		_not_ part of the public API for HDF5 application developers.
+ *
+ * Note:	This routine must be called as a "pair" with
+ * 		H5VLrestore_lib_state.  It can be called before / after /
+ * 		independently of H5VLfree_lib_state.
+ *
+ * Return:      Success:    Non-negative
+ *              Failure:    Negative
+ *
+ * Programmer:	Quincey Koziol
+ *		Saturday, February 23, 2019
+ *
+ *---------------------------------------------------------------------------
+ */
+herr_t
+H5VLreset_lib_state(void)
+{
+    herr_t ret_value = SUCCEED; /* Return value */
+
+    /* Must use this, to avoid modifying the API context stack in FUNC_ENTER */
+    FUNC_ENTER_API_NOINIT
+    H5TRACE0("e","");
+
+    /* Reset the library state */
+    if(H5VL_reset_lib_state() < 0)
+        HGOTO_ERROR(H5E_VOL, H5E_CANTRESET, FAIL, "can't reset library state")
+
+done:
+    FUNC_LEAVE_API_NOINIT(ret_value)
+} /* H5VLreset_lib_state() */
+
+
+/*---------------------------------------------------------------------------
+ * Function:    H5VLfree_lib_state
+ *
+ * Purpose:     Free a retrieved library state.
+ *
+ * Note:	This routine is _only_ for HDF5 VOL connector authors!  It is
+ *		_not_ part of the public API for HDF5 application developers.
+ *
+ * Note:	This routine must be called as a "pair" with
+ * 		H5VLretrieve_lib_state.
+ *
+ * Return:      Success:    Non-negative
+ *              Failure:    Negative
+ *
+ * Programmer:	Quincey Koziol
+ *		Thursday, January 10, 2019
+ *
+ *---------------------------------------------------------------------------
+ */
+herr_t
+H5VLfree_lib_state(void *state)
+{
+    herr_t ret_value = SUCCEED; /* Return value */
+
+    FUNC_ENTER_API(FAIL)
+    H5TRACE1("e", "*x", state);
+
+    /* Check args */
+    if(NULL == state)
+        HGOTO_ERROR(H5E_VOL, H5E_BADVALUE, FAIL, "invalid state pointer")
+
+    /* Free the library state */
+    if(H5VL_free_lib_state(state) < 0)
+        HGOTO_ERROR(H5E_VOL, H5E_CANTRELEASE, FAIL, "can't free library state")
+
+done:
+    FUNC_LEAVE_API(ret_value)
+} /* H5VLfree_lib_state() */
+
diff --git a/src/H5VLint.c b/src/H5VLint.c
index 5aa25d2..7aeea02 100644
--- a/src/H5VLint.c
+++ b/src/H5VLint.c
@@ -51,7 +51,7 @@
 /* Object wrapping context info */
 typedef struct H5VL_wrap_ctx_t {
     unsigned rc;                /* Ref. count for the # of times the context was set / reset */
-    const H5VL_t *connector;    /* VOL connector for "outermost" class to start wrap */
+    H5VL_t *connector;          /* VOL connector for "outermost" class to start wrap */
     void *obj_wrap_ctx;         /* "wrap context" for outermost connector */
 } H5VL_wrap_ctx_t;
 
@@ -68,7 +68,10 @@ static herr_t H5VL__free_cls(H5VL_class_t *cls);
 static void *H5VL__wrap_obj(void *obj, H5I_type_t obj_type);
 static H5VL_object_t *H5VL__new_vol_obj(H5I_type_t type, void *object,
     H5VL_t *vol_connector, hbool_t wrap_obj);
+static int64_t H5VL__conn_inc_rc(H5VL_t *connector);
+static int64_t H5VL__conn_dec_rc(H5VL_t *connector);
 static void *H5VL__object(hid_t id, H5I_type_t obj_type);
+static herr_t H5VL__free_vol_wrapper(H5VL_wrap_ctx_t *vol_wrap_ctx);
 
 
 /*********************/
@@ -317,7 +320,7 @@ H5VL__new_vol_obj(H5I_type_t type, void *object, H5VL_t *vol_connector, hbool_t
         new_vol_obj->data = object;
 
     /* Bump the reference count on the VOL connector */
-    vol_connector->nrefs++;
+    H5VL__conn_inc_rc(vol_connector);
 
     /* If this is a datatype, we have to hide the VOL object under the H5T_t pointer */
     if(H5I_DATATYPE == type) {
@@ -550,6 +553,76 @@ done:
 
 
 /*-------------------------------------------------------------------------
+ * Function:    H5VL__conn_inc_rc
+ *
+ * Purpose:     Wrapper to increment the ref. count on a connector.
+ *
+ * Return:      Current ref. count (can't fail)
+ *
+ * Programmer:  Quincey Koziol
+ *              February 23, 2019
+ *
+ *-------------------------------------------------------------------------
+ */
+static int64_t
+H5VL__conn_inc_rc(H5VL_t *connector)
+{
+    FUNC_ENTER_STATIC_NOERR
+
+    /* Check arguments */
+    HDassert(connector);
+
+    /* Increment refcount for connector */
+    connector->nrefs++;
+
+    FUNC_LEAVE_NOAPI(connector->nrefs)
+} /* end H5VL__conn_inc_rc() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5VL__conn_dec_rc
+ *
+ * Purpose:     Wrapper to decrement the ref. count on a connector.
+ *
+ * Return:      Current ref. count (>=0) on success, <0 on failure
+ *
+ * Programmer:  Quincey Koziol
+ *              February 23, 2019
+ *
+ *-------------------------------------------------------------------------
+ */
+static int64_t
+H5VL__conn_dec_rc(H5VL_t *connector)
+{
+    int64_t ret_value = -1;     /* Return value */
+
+    FUNC_ENTER_STATIC
+
+    /* Check arguments */
+    HDassert(connector);
+
+    /* Decrement refcount for connector */
+    connector->nrefs--;
+
+    /* Check for last reference */
+    if(0 == connector->nrefs) {
+        if(H5I_dec_ref(connector->id) < 0)
+            HGOTO_ERROR(H5E_VOL, H5E_CANTDEC, FAIL, "unable to decrement ref count on VOL connector")
+        H5FL_FREE(H5VL_t, connector);
+
+        /* Set return value */
+        ret_value = 0;
+    } /* end if */
+    else
+        /* Set return value */
+        ret_value = connector->nrefs;
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5VL__conn_dec_rc() */
+
+
+/*-------------------------------------------------------------------------
  * Function:    H5VL_free_object
  *
  * Purpose:     Wrapper to unregister an object ID with a VOL aux struct
@@ -562,20 +635,16 @@ done:
 herr_t
 H5VL_free_object(H5VL_object_t *vol_obj)
 {
-    herr_t ret_value = SUCCEED;
+    herr_t ret_value = SUCCEED;         /* Return value */
 
-    FUNC_ENTER_NOAPI(SUCCEED)
+    FUNC_ENTER_NOAPI(FAIL)
 
     /* Check arguments */
     HDassert(vol_obj);
 
-    vol_obj->connector->nrefs --;
-
-    if(0 == vol_obj->connector->nrefs) {
-        if(H5I_dec_ref(vol_obj->connector->id) < 0)
-            HGOTO_ERROR(H5E_VOL, H5E_CANTDEC, FAIL, "unable to decrement ref count on VOL connector")
-        vol_obj->connector = H5FL_FREE(H5VL_t, vol_obj->connector);
-    } /* end if */
+    /* Decrement refcount on connector */
+    if(H5VL__conn_dec_rc(vol_obj->connector) < 0)
+        HGOTO_ERROR(H5E_VOL, H5E_CANTDEC, FAIL, "unable to decrement ref count on VOL connector")
 
     vol_obj = H5FL_FREE(H5VL_object_t, vol_obj);
 
@@ -952,6 +1021,189 @@ done:
 
 
 /*-------------------------------------------------------------------------
+ * Function:    H5VL_retrieve_lib_state
+ *
+ * Purpose:     Retrieve the state of the library.
+ *
+ * Note:        Currently just retrieves the API context state, but could be
+ *		expanded in the future.
+ *
+ * Return:      Success:    Non-negative, *state set
+ *              Failure:    Negative, *state unset
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5VL_retrieve_lib_state(void **state)
+{
+    herr_t ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_NOAPI(FAIL)
+
+    /* Sanity checks */
+    HDassert(state);
+
+    /* Retrieve the API context state */
+    if(H5CX_retrieve_state((H5CX_state_t **)state) < 0)
+        HGOTO_ERROR(H5E_VOL, H5E_CANTGET, FAIL, "can't get API context state")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5VL_retrieve_lib_state() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5VL_restore_lib_state
+ *
+ * Purpose:     Restore the state of the library.
+ *
+ * Note:        Currently just restores the API context state, but could be
+ *		expanded in the future.
+ *
+ * Return:      SUCCEED / FAIL
+ *
+ * Programmer:	Quincey Koziol
+ *		Thursday, January 10, 2019
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5VL_restore_lib_state(const void *state)
+{
+    herr_t ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_NOAPI(FAIL)
+
+    /* Sanity checks */
+    HDassert(state);
+
+    /* Push a new API context on the stack */
+    if(H5CX_push() < 0)
+        HGOTO_ERROR(H5E_VOL, H5E_CANTSET, FAIL, "can't push API context")
+
+    /* Restore the API context state */
+    if(H5CX_restore_state((const H5CX_state_t *)state) < 0)
+        HGOTO_ERROR(H5E_VOL, H5E_CANTSET, FAIL, "can't set API context state")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5VL_restore_lib_state() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5VL_reset_lib_state
+ *
+ * Purpose:     Reset the state of the library, undoing affects of
+ *		H5VL_restore_lib_state.
+ *
+ * Note:        Currently just resets the API context state, but could be
+ *		expanded in the future.
+ *
+ * Note:	This routine must be called as a "pair" with
+ * 		H5VL_restore_lib_state.  It can be called before / after /
+ * 		independently of H5VL_free_lib_state.
+ *
+ * Return:      SUCCEED / FAIL
+ *
+ * Programmer:	Quincey Koziol
+ *		Saturday, February 23, 2019
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5VL_reset_lib_state(void)
+{
+    herr_t ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_NOAPI(FAIL)
+
+    /* Pop the API context off the stack */
+    if(H5CX_pop() < 0)
+        HGOTO_ERROR(H5E_VOL, H5E_CANTRESET, FAIL, "can't pop API context")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5VL_reset_lib_state() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5VL_free_lib_state
+ *
+ * Purpose:     Free a library state.
+ *
+ * Note:	This routine must be called as a "pair" with
+ * 		H5VL_retrieve_lib_state.
+ *
+ * Return:      SUCCEED / FAIL
+ *
+ * Programmer:	Quincey Koziol
+ *		Thursday, January 10, 2019
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5VL_free_lib_state(void *state)
+{
+    herr_t ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_NOAPI(FAIL)
+
+    /* Sanity checks */
+    HDassert(state);
+
+    /* Free the API context state */
+    if(H5CX_free_state((H5CX_state_t *)state) < 0)
+        HGOTO_ERROR(H5E_VOL, H5E_CANTRELEASE, FAIL, "can't free API context state")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5VL_free_lib_state() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5VL__free_vol_wrapper
+ *
+ * Purpose:     Free object wrapping context for VOL connector
+ *
+ * Return:      SUCCEED / FAIL
+ *
+ * Programmer:	Quincey Koziol
+ *		Wednesday, January  9, 2019
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5VL__free_vol_wrapper(H5VL_wrap_ctx_t *vol_wrap_ctx)
+{
+    herr_t ret_value = SUCCEED;                 /* Return value */
+
+    FUNC_ENTER_STATIC
+
+    /* Sanity check */
+    HDassert(vol_wrap_ctx);
+    HDassert(0 == vol_wrap_ctx->rc);
+    HDassert(vol_wrap_ctx->connector);
+    HDassert(vol_wrap_ctx->connector->cls);
+
+    /* If there is a VOL connector object wrapping context, release it */
+    if(vol_wrap_ctx->obj_wrap_ctx)
+        /* Release the VOL connector's object wrapping context */
+        if((*vol_wrap_ctx->connector->cls->wrap_cls.free_wrap_ctx)(vol_wrap_ctx->obj_wrap_ctx) < 0)
+            HGOTO_ERROR(H5E_VOL, H5E_CANTRELEASE, FAIL, "unable to release connector's object wrapping context")
+
+    /* Decrement refcount on connector */
+    if(H5VL__conn_dec_rc(vol_wrap_ctx->connector) < 0)
+        HGOTO_ERROR(H5E_VOL, H5E_CANTDEC, FAIL, "unable to decrement ref count on VOL connector")
+
+    /* Release object wrapping context */
+    H5FL_FREE(H5VL_wrap_ctx_t, vol_wrap_ctx);
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5VL__free_vol_wrapper() */
+
+
+/*-------------------------------------------------------------------------
  * Function:    H5VL_set_vol_wrapper
  *
  * Purpose:     Set up object wrapping context for current VOL connector
@@ -961,7 +1213,7 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5VL_set_vol_wrapper(void *obj, const H5VL_t *connector)
+H5VL_set_vol_wrapper(void *obj, H5VL_t *connector)
 {
     H5VL_wrap_ctx_t *vol_wrap_ctx = NULL;       /* Object wrapping context */
     void *obj_wrap_ctx = NULL;          /* VOL connector's wrapping context */
@@ -993,8 +1245,11 @@ H5VL_set_vol_wrapper(void *obj, const H5VL_t *connector)
         if(NULL == (vol_wrap_ctx = H5FL_MALLOC(H5VL_wrap_ctx_t)))
             HGOTO_ERROR(H5E_VOL, H5E_CANTALLOC, FAIL, "can't allocate VOL wrap context")
 
+        /* Increment the outstanding objects that are using the connector */
+        H5VL__conn_inc_rc(connector);
+
         /* Set up VOL object wrapper context */
-        vol_wrap_ctx->rc = 1;;
+        vol_wrap_ctx->rc = 1;
         vol_wrap_ctx->connector = connector;
         vol_wrap_ctx->obj_wrap_ctx = obj_wrap_ctx;
     } /* end if */
@@ -1016,6 +1271,80 @@ done:
 
 
 /*-------------------------------------------------------------------------
+ * Function:    H5VL_inc_vol_wrapper
+ *
+ * Purpose:     Increment refcount on object wrapping context
+ *
+ * Return:      SUCCEED / FAIL
+ *
+ * Programmer:	Quincey Koziol
+ *		Wednesday, January  9, 2019
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5VL_inc_vol_wrapper(void *_vol_wrap_ctx)
+{
+    H5VL_wrap_ctx_t *vol_wrap_ctx = (H5VL_wrap_ctx_t *)_vol_wrap_ctx; /* VOL object wrapping context */
+    herr_t ret_value = SUCCEED;                 /* Return value */
+
+    FUNC_ENTER_NOAPI(FAIL)
+
+    /* Check for valid, active VOL object wrap context */
+    if(NULL == vol_wrap_ctx)
+        HGOTO_ERROR(H5E_VOL, H5E_BADVALUE, FAIL, "no VOL object wrap context?")
+    if(0 == vol_wrap_ctx->rc)
+        HGOTO_ERROR(H5E_VOL, H5E_BADVALUE, FAIL, "bad VOL object wrap context refcount?")
+
+    /* Increment ref count on wrapping context */
+    vol_wrap_ctx->rc++;
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5VL_inc_vol_wrapper() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5VL_dec_vol_wrapper
+ *
+ * Purpose:     Decrement refcount on object wrapping context, releasing it
+ *		if the refcount drops to zero.
+ *
+ * Return:      SUCCEED / FAIL
+ *
+ * Programmer:	Quincey Koziol
+ *		Wednesday, January  9, 2019
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5VL_dec_vol_wrapper(void *_vol_wrap_ctx)
+{
+    H5VL_wrap_ctx_t *vol_wrap_ctx = (H5VL_wrap_ctx_t *)_vol_wrap_ctx; /* VOL object wrapping context */
+    herr_t ret_value = SUCCEED;                 /* Return value */
+
+    FUNC_ENTER_NOAPI(FAIL)
+
+    /* Check for valid, active VOL object wrap context */
+    if(NULL == vol_wrap_ctx)
+        HGOTO_ERROR(H5E_VOL, H5E_BADVALUE, FAIL, "no VOL object wrap context?")
+    if(0 == vol_wrap_ctx->rc)
+        HGOTO_ERROR(H5E_VOL, H5E_BADVALUE, FAIL, "bad VOL object wrap context refcount?")
+
+    /* Decrement ref count on wrapping context */
+    vol_wrap_ctx->rc--;
+
+    /* Release context if the ref count drops to zero */
+    if(0 == vol_wrap_ctx->rc)
+        if(H5VL__free_vol_wrapper(vol_wrap_ctx) < 0)
+            HGOTO_ERROR(H5E_VOL, H5E_CANTRELEASE, FAIL, "unable to release VOL object wrapping context")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5VL_dec_vol_wrapper() */
+
+
+/*-------------------------------------------------------------------------
  * Function:    H5VL_reset_vol_wrapper
  *
  * Purpose:     Reset object wrapping context for current VOL connector
@@ -1045,25 +1374,18 @@ H5VL_reset_vol_wrapper(void)
 
     /* Release context if the ref count drops to zero */
     if(0 == vol_wrap_ctx->rc) {
-        /* If there is a VOL connector object wrapping context, release it */
-        if(vol_wrap_ctx->obj_wrap_ctx) {
-            /* Release the VOL connector's object wrapping context */
-            if((*vol_wrap_ctx->connector->cls->wrap_cls.free_wrap_ctx)(vol_wrap_ctx->obj_wrap_ctx) < 0)
-                HGOTO_ERROR(H5E_VOL, H5E_CANTRELEASE, FAIL, "unable to release connector's object wrapping context")
-        } /* end if */
-
         /* Release object wrapping context */
-        H5FL_FREE(H5VL_wrap_ctx_t, vol_wrap_ctx);
+        if(H5VL__free_vol_wrapper(vol_wrap_ctx) < 0)
+            HGOTO_ERROR(H5E_VOL, H5E_CANTRELEASE, FAIL, "unable to release VOL object wrapping context")
 
         /* Reset the wrapper context */
         if(H5CX_set_vol_wrap_ctx(NULL) < 0)
             HGOTO_ERROR(H5E_VOL, H5E_CANTSET, FAIL, "can't set VOL object wrap context")
     } /* end if */
-    else {
+    else
         /* Save the updated wrapper context */
         if(H5CX_set_vol_wrap_ctx(vol_wrap_ctx) < 0)
             HGOTO_ERROR(H5E_VOL, H5E_CANTSET, FAIL, "can't set VOL object wrap context")
-    } /* end else */
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
diff --git a/src/H5VLprivate.h b/src/H5VLprivate.h
index 283c77a..ac77ee0 100644
--- a/src/H5VLprivate.h
+++ b/src/H5VLprivate.h
@@ -41,8 +41,8 @@ typedef struct H5VL_object_t {
 
 /* Internal structure to hold the connector ID & info for FAPLs */
 typedef struct H5VL_connector_prop_t {
-    hid_t               connector_id;   /* VOL connector's ID                                   */
-    const void         *connector_info; /* VOL connector info, for open callbacks               */
+    hid_t       connector_id;           /* VOL connector's ID                                   */
+    void        *connector_info;        /* VOL connector info, for open callbacks               */
 } H5VL_connector_prop_t;
 
 /* Which kind of VOL connector field to use for searching */
@@ -92,11 +92,19 @@ H5_DLL herr_t H5VL_free_object(H5VL_object_t *obj);
 H5_DLL herr_t H5VL_get_wrap_ctx(const H5VL_class_t *connector, void *obj,
     void **wrap_ctx);
 H5_DLL herr_t H5VL_free_wrap_ctx(const H5VL_class_t *connector, void *wrap_ctx);
-H5_DLL herr_t H5VL_set_vol_wrapper(void *obj, const H5VL_t *vol_connector);
+H5_DLL herr_t H5VL_set_vol_wrapper(void *obj, H5VL_t *vol_connector);
+H5_DLL herr_t H5VL_inc_vol_wrapper(void *vol_wrap_ctx);
+H5_DLL herr_t H5VL_dec_vol_wrapper(void *vol_wrap_ctx);
 H5_DLL herr_t H5VL_reset_vol_wrapper(void);
 H5_DLL void * H5VL_wrap_object(const H5VL_class_t *connector, void *wrap_ctx,
     void *obj, H5I_type_t obj_type);
 
+/* Library state functions */
+H5_DLL herr_t H5VL_retrieve_lib_state(void **state);
+H5_DLL herr_t H5VL_restore_lib_state(const void *state);
+H5_DLL herr_t H5VL_reset_lib_state(void);
+H5_DLL herr_t H5VL_free_lib_state(void *state);
+
 /* ID registration functions */
 H5_DLL hid_t H5VL_register(H5I_type_t type, void *object, H5VL_t *vol_connector, hbool_t app_ref);
 H5_DLL hid_t H5VL_wrap_register(H5I_type_t type, void *obj, hbool_t app_ref);
diff --git a/src/H5VLpublic.h b/src/H5VLpublic.h
index 72e69b8..cf6246b 100644
--- a/src/H5VLpublic.h
+++ b/src/H5VLpublic.h
@@ -450,6 +450,10 @@ H5_DLL herr_t H5VLunregister_connector(hid_t connector_id);
 H5_DLL herr_t H5VLcmp_connector_cls(int *cmp, hid_t connector_id1, hid_t connector_id2);
 H5_DLL hid_t H5VLwrap_register(void *obj, H5I_type_t type);
 H5_DLL void *H5VLobject(hid_t obj_id);
+H5_DLL herr_t H5VLretrieve_lib_state(void **state);
+H5_DLL herr_t H5VLrestore_lib_state(const void *state);
+H5_DLL herr_t H5VLreset_lib_state(void);
+H5_DLL herr_t H5VLfree_lib_state(void *state);
 
 
 /* Public wrappers for generic callbacks */
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index 276cf09..772f790 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -352,12 +352,17 @@ add_executable (ttsafe ${ttsafe_SOURCES})
 target_include_directories(ttsafe PRIVATE "${HDF5_SRC_DIR};${HDF5_BINARY_DIR};$<$<BOOL:${HDF5_ENABLE_PARALLEL}>:${MPI_C_INCLUDE_DIRS}>")
 TARGET_C_PROPERTIES (ttsafe STATIC)
 target_link_libraries (ttsafe PRIVATE ${HDF5_LIB_TARGET} ${HDF5_TEST_LIB_TARGET})
+if (NOT WIN32)
+  target_link_libraries (ttsafe
+    PRIVATE $<$<BOOL:${HDF5_ENABLE_THREADSAFE}>:Threads::Threads>
+  )
+endif ()
 set_target_properties (ttsafe PROPERTIES FOLDER test)
 if (BUILD_SHARED_LIBS)
   add_executable (ttsafe-shared ${ttsafe_SOURCES})
   target_include_directories(ttsafe-shared PRIVATE "${HDF5_SRC_DIR};${HDF5_BINARY_DIR};$<$<BOOL:${HDF5_ENABLE_PARALLEL}>:${MPI_C_INCLUDE_DIRS}>")
   TARGET_C_PROPERTIES (ttsafe-shared SHARED)
-  target_link_libraries (ttsafe-shared PRIVATE ${HDF5_TEST_LIBSH_TARGET} ${HDF5_LIBSH_TARGET})
+  target_link_libraries (ttsafe-shared PRIVATE ${HDF5_TEST_LIBSH_TARGET} ${HDF5_LIBSH_TARGET} $<$<BOOL:${HDF5_ENABLE_THREADSAFE}>:Threads::Threads>)
   set_target_properties (ttsafe-shared PROPERTIES FOLDER test)
 endif ()