CMake/Modules/FindHDF5.cmake

#.rst:
# FindHDF5
# --------
#
# Find HDF5, a library for reading and writing self describing array data.
#
#
#
# This module invokes the HDF5 wrapper compiler that should be installed
# alongside HDF5.  Depending upon the HDF5 Configuration, the wrapper
# compiler is called either h5cc or h5pcc.  If this succeeds, the module
# will then call the compiler with the -show argument to see what flags
# are used when compiling an HDF5 client application.
#
# The module will optionally accept the COMPONENTS argument.  If no
# COMPONENTS are specified, then the find module will default to finding
# only the HDF5 C library.  If one or more COMPONENTS are specified, the
# module will attempt to find the language bindings for the specified
# components.  The only valid components are C, CXX, Fortran, HL, and
# Fortran_HL.  If the COMPONENTS argument is not given, the module will
# attempt to find only the C bindings.
#
# On UNIX systems, this module will read the variable
# HDF5_USE_STATIC_LIBRARIES to determine whether or not to prefer a
# static link to a dynamic link for HDF5 and all of it's dependencies.
# To use this feature, make sure that the HDF5_USE_STATIC_LIBRARIES
# variable is set before the call to find_package.
#
# To provide the module with a hint about where to find your HDF5
# installation, you can set the environment variable HDF5_ROOT.  The
# Find module will then look in this path when searching for HDF5
# executables, paths, and libraries.
#
# Both the serial and parallel HDF5 wrappers are considered and the first
# directory to contain either one will be used.  In the event that both appear
# in the same directory the serial version is preferentially selected. This
# behavior can be reversed by setting the variable HDF5_PREFER_PARALLEL to
# true.
#
# In addition to finding the includes and libraries required to compile
# an HDF5 client application, this module also makes an effort to find
# tools that come with the HDF5 distribution that may be useful for
# regression testing.
#
# This module will define the following variables:
#
# ::
#
#   HDF5_FOUND - true if HDF5 was found on the system
#   HDF5_VERSION - HDF5 version in format Major.Minor.Release
#   HDF5_INCLUDE_DIRS - Location of the hdf5 includes
#   HDF5_INCLUDE_DIR - Location of the hdf5 includes (deprecated)
#   HDF5_DEFINITIONS - Required compiler definitions for HDF5
#   HDF5_LIBRARIES - Required libraries for all requested bindings
#   HDF5_HL_LIBRARIES - Required libraries for the HDF5 high level API for all
#                       bindings, if the HL component is enabled
#
# Available components are: C CXX Fortran and HL.  For each enabled language
# binding, a corresponding HDF5_${LANG}_LIBRARIES variable will be defined.
# If the HL component is enabled, then an HDF5_${LANG}_HL_LIBRARIES will
# also be defined.  With all components enabled, the following variables will be defined:
#
# ::
#
#   HDF5_C_LIBRARIES - Required libraries for the HDF5 C bindings
#   HDF5_CXX_LIBRARIES - Required libraries for the HDF5 C++ bindings
#   HDF5_Fortran_LIBRARIES - Required libraries for the HDF5 Fortran bindings
#   HDF5_C_HL_LIBRARIES - Required libraries for the high level C bindings
#   HDF5_CXX_HL_LIBRARIES - Required libraries for the high level C++ bindings
#   HDF5_Fortran_HL_LIBRARIES - Required libraries for the high level Fortran
#                               bindings.
#
#   HDF5_IS_PARALLEL - Whether or not HDF5 was found with parallel IO support
#   HDF5_C_COMPILER_EXECUTABLE - the path to the HDF5 C wrapper compiler
#   HDF5_CXX_COMPILER_EXECUTABLE - the path to the HDF5 C++ wrapper compiler
#   HDF5_Fortran_COMPILER_EXECUTABLE - the path to the HDF5 Fortran wrapper compiler
#   HDF5_C_COMPILER_EXECUTABLE_NO_INTERROGATE - path to the primary C compiler
#                                               which is also the HDF5 wrapper
#   HDF5_CXX_COMPILER_EXECUTABLE_NO_INTERROGATE - path to the primary C++
#                                                 compiler which is also
#                                                 the HDF5 wrapper
#   HDF5_Fortran_COMPILER_EXECUTABLE_NO_INTERROGATE - path to the primary
#                                                     Fortran compiler which
#                                                     is also the HDF5 wrapper
#   HDF5_DIFF_EXECUTABLE - the path to the HDF5 dataset comparison tool
#
# The following variable can be set to guide the search for HDF5 libraries and includes:
#
# HDF5_ROOT

#=============================================================================
# Copyright 2015 Axel Huebl, Helmholtz-Zentrum Dresden - Rossendorf
# Copyright 2009 Kitware, Inc.
#
# Distributed under the OSI-approved BSD License (the "License");
# see accompanying file Copyright.txt for details.
#
# This software is distributed WITHOUT ANY WARRANTY; without even the
# implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
# See the License for more information.
#=============================================================================
# (To distribute this file outside of CMake, substitute the full
#  License text for the above reference.)

# This module is maintained by Will Dicharry <wdicharry@stellarscience.com>.

include(${CMAKE_CURRENT_LIST_DIR}/SelectLibraryConfigurations.cmake)
include(${CMAKE_CURRENT_LIST_DIR}/FindPackageHandleStandardArgs.cmake)

# List of the valid HDF5 components
set(HDF5_VALID_LANGUAGE_BINDINGS C CXX Fortran)

# Validate the list of find components.
set(HDF5_LANGUAGE_BINDINGS)
if(NOT HDF5_FIND_COMPONENTS)
  get_property(__langs GLOBAL PROPERTY ENABLED_LANGUAGES)
  foreach(__lang IN LISTS __langs)
    if(__lang MATCHES "^(C|CXX|Fortran)$")
      list(APPEND HDF5_LANGUAGE_BINDINGS ${__lang})
    endif()
  endforeach()
  set(FIND_HL ON)
else()
  # add the extra specified components, ensuring that they are valid.
  set(FIND_HL OFF)
  foreach(component IN LISTS HDF5_FIND_COMPONENTS)
    list(FIND HDF5_VALID_LANGUAGE_BINDINGS ${component} component_location)
    if(NOT component_location EQUAL -1)
      list(APPEND HDF5_LANGUAGE_BINDINGS ${component})
    elseif(component STREQUAL "HL")
      set(FIND_HL ON)
    elseif(component STREQUAL "Fortran_HL") # only for compatibility
      list(APPEND HDF5_LANGUAGE_BINDINGS Fortran)
      set(FIND_HL ON)
    else()
      message(FATAL_ERROR "${component} is not a valid HDF5 component.")
    endif()
  endforeach()
  if(NOT HDF5_LANGUAGE_BINDINGS)
    get_property(__langs GLOBAL PROPERTY ENABLED_LANGUAGES)
    foreach(__lang IN LISTS __langs)
      if(__lang MATCHES "^(C|CXX|Fortran)$")
        list(APPEND HDF5_LANGUAGE_BINDINGS ${__lang})
      endif()
    endforeach()
  endif()
  list(REMOVE_DUPLICATES HDF5_LANGUAGE_BINDINGS)
endif()

# Determine whether to search for serial or parallel executable first
if(HDF5_PREFER_PARALLEL)
  set(HDF5_C_COMPILER_NAMES h5pcc h5cc)
  set(HDF5_CXX_COMPILER_NAMES h5pc++ h5c++)
  set(HDF5_Fortran_COMPILER_NAMES h5pfc h5fc)
else()
  set(HDF5_C_COMPILER_NAMES h5cc h5pcc)
  set(HDF5_CXX_COMPILER_NAMES h5c++ h5pc++)
  set(HDF5_Fortran_COMPILER_NAMES h5fc h5pfc)
endif()

# We may have picked up some duplicates in various lists during the above
# process for the language bindings (both the C and C++ bindings depend on
# libz for example).  Remove the duplicates. It appears that the default
# CMake behavior is to remove duplicates from the end of a list. However,
# for link lines, this is incorrect since unresolved symbols are searched
# for down the link line. Therefore, we reverse the list, remove the
# duplicates, and then reverse it again to get the duplicates removed from
# the beginning.
macro(_HDF5_remove_duplicates_from_beginning _list_name)
  if(${_list_name})
    list(REVERSE ${_list_name})
    list(REMOVE_DUPLICATES ${_list_name})
    list(REVERSE ${_list_name})
  endif()
endmacro()


# Test first if the current compilers automatically wrap HDF5

function(_HDF5_test_regular_compiler_C success version)
  set(scratch_directory
    ${CMAKE_CURRENT_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/hdf5)
  if(NOT ${success} OR
     NOT EXISTS ${scratch_directory}/compiler_has_h5_c)
    set(test_file ${scratch_directory}/cmake_hdf5_test.c)
    file(WRITE ${test_file}
      "#include <hdf5.h>\n"
      "#include <hdf5_hl.h>\n"
      "int main(void) {\n"
      "  char const* info_ver = \"INFO\" \":\" H5_VERSION;\n"
      "  hid_t fid;\n"
      "  fid = H5Fcreate(\"foo.h5\",H5F_ACC_TRUNC,H5P_DEFAULT,H5P_DEFAULT);\n"
      "  return 0;\n"
      "}")
    try_compile(${success} ${scratch_directory} ${test_file}
      COPY_FILE ${scratch_directory}/compiler_has_h5_c
    )
  endif()
  if(${success})
    file(STRINGS ${scratch_directory}/compiler_has_h5_c INFO_VER
      REGEX "^INFO:([0-9]+\\.[0-9]+\\.[0-9]+)(-patch([0-9]+))?"
    )
    string(REGEX MATCH "^INFO:([0-9]+\\.[0-9]+\\.[0-9]+)(-patch([0-9]+))?"
      INFO_VER "${INFO_VER}"
    )
    set(${version} ${CMAKE_MATCH_1})
    if(CMAKE_MATCH_3)
      set(${version} ${HDF5_CXX_VERSION}.${CMAKE_MATCH_3})
    endif()
    set(${version} ${${version}} PARENT_SCOPE)
  endif()
endfunction()

function(_HDF5_test_regular_compiler_CXX success version)
  set(scratch_directory ${CMAKE_CURRENT_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/hdf5)
  if(NOT ${success} OR
     NOT EXISTS ${scratch_directory}/compiler_has_h5_cxx)
    set(test_file ${scratch_directory}/cmake_hdf5_test.cxx)
    file(WRITE ${test_file}
      "#include <H5Cpp.h>\n"
      "#ifndef H5_NO_NAMESPACE\n"
      "using namespace H5;\n"
      "#endif\n"
      "int main(int argc, char **argv) {\n"
      "  char const* info_ver = \"INFO\" \":\" H5_VERSION;\n"
      "  H5File file(\"foo.h5\", H5F_ACC_TRUNC);\n"
      "  return 0;\n"
      "}")
    try_compile(${success} ${scratch_directory} ${test_file}
      COPY_FILE ${scratch_directory}/compiler_has_h5_cxx
    )
  endif()
  if(${success})
    file(STRINGS ${scratch_directory}/compiler_has_h5_cxx INFO_VER
      REGEX "^INFO:([0-9]+\\.[0-9]+\\.[0-9]+)(-patch([0-9]+))?"
    )
    string(REGEX MATCH "^INFO:([0-9]+\\.[0-9]+\\.[0-9]+)(-patch([0-9]+))?"
      INFO_VER "${INFO_VER}"
    )
    set(${version} ${CMAKE_MATCH_1})
    if(CMAKE_MATCH_3)
      set(${version} ${HDF5_CXX_VERSION}.${CMAKE_MATCH_3})
    endif()
    set(${version} ${${version}} PARENT_SCOPE)
  endif()
endfunction()

function(_HDF5_test_regular_compiler_Fortran success)
  if(NOT ${success})
    set(scratch_directory
      ${CMAKE_CURRENT_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/hdf5)
    set(test_file ${scratch_directory}/cmake_hdf5_test.f90)
    file(WRITE ${test_file}
      "program hdf5_hello\n"
      "  use hdf5\n"
      "  use h5lt\n"
      "  use h5ds\n"
      "  integer error\n"
      "  call h5open_f(error)\n"
      "  call h5close_f(error)\n"
      "end\n")
    try_compile(${success} ${scratch_directory} ${test_file})
  endif()
endfunction()

# Invoke the HDF5 wrapper compiler.  The compiler return value is stored to the
# return_value argument, the text output is stored to the output variable.
macro( _HDF5_invoke_compiler language output return_value version)
    set(${version})
    exec_program( ${HDF5_${language}_COMPILER_EXECUTABLE}
        ARGS -show
        OUTPUT_VARIABLE ${output}
        RETURN_VALUE ${return_value}
    )
    if(NOT ${${return_value}} EQUAL 0)
        message(STATUS
          "Unable to determine HDF5 ${language} flags from HDF5 wrapper.")
    endif()
    exec_program( ${HDF5_${language}_COMPILER_EXECUTABLE}
        ARGS -showconfig
        OUTPUT_VARIABLE config_output
        RETURN_VALUE config_return
    )
    if(NOT ${return_value} EQUAL 0)
        message( STATUS
          "Unable to determine HDF5 ${language} version from HDF5 wrapper.")
    endif()
    string(REGEX MATCH "HDF5 Version: ([a-zA-Z0-9\\.\\-]*)" version_match "${config_output}")
    if(version_match)
        string(REPLACE "HDF5 Version: " "" ${version} "${version_match}")
        string(REPLACE "-patch" "." ${version} "${${version}}")
    endif()
endmacro()

# Parse a compile line for definitions, includes, library paths, and libraries.
macro( _HDF5_parse_compile_line
    compile_line_var
    include_paths
    definitions
    library_paths
    libraries
    libraries_hl)

    # Match the include paths
    string( REGEX MATCHALL "-I([^\" ]+)" include_path_flags
        "${${compile_line_var}}"
    )
    foreach( IPATH ${include_path_flags} )
        string( REGEX REPLACE "^-I" "" IPATH ${IPATH} )
        string( REPLACE "//" "/" IPATH ${IPATH} )
        list( APPEND ${include_paths} ${IPATH} )
    endforeach()

    # Match the definitions
    string( REGEX MATCHALL "-D[^ ]*" definition_flags "${${compile_line_var}}" )
    foreach( DEF ${definition_flags} )
        list( APPEND ${definitions} ${DEF} )
    endforeach()

    # Match the library paths
    string( REGEX MATCHALL "-L([^\" ]+|\"[^\"]+\")" library_path_flags
        "${${compile_line_var}}"
    )

    foreach( LPATH ${library_path_flags} )
        string( REGEX REPLACE "^-L" "" LPATH ${LPATH} )
        string( REPLACE "//" "/" LPATH ${LPATH} )
        list( APPEND ${library_paths} ${LPATH} )
    endforeach()

    # now search for the library names specified in the compile line (match -l...)
    # match only -l's preceded by a space or comma
    # this is to exclude directory names like xxx-linux/
    string( REGEX MATCHALL "[, ]-l([^\", ]+)" library_name_flags
        "${${compile_line_var}}" )
    # strip the -l from all of the library flags and add to the search list
    foreach( LIB ${library_name_flags} )
        string( REGEX REPLACE "^[, ]-l" "" LIB ${LIB} )
        if(LIB MATCHES ".*_hl")
            list(APPEND ${libraries_hl} ${LIB})
        else()
            list(APPEND ${libraries} ${LIB})
        endif()
    endforeach()
endmacro()

# Try to find HDF5 using an installed hdf5-config.cmake
if(NOT HDF5_FOUND AND NOT HDF5_ROOT)
    find_package(HDF5 QUIET NO_MODULE)
    if( HDF5_FOUND)
        set(HDF5_INCLUDE_DIRS ${HDF5_INCLUDE_DIR})
        set(HDF5_LIBRARIES)
        set(HDF5_C_TARGET hdf5)
        set(HDF5_C_HL_TARGET hdf5_hl)
        set(HDF5_CXX_TARGET hdf5_cpp)
        set(HDF5_CXX_HL_TARGET hdf5_hl_cpp)
        set(HDF5_Fortran_TARGET hdf5_fortran)
        set(HDF5_Fortran_HL_TARGET hdf5_hl_fortran)
        if(HDF5_USE_STATIC_LIBRARIES)
            set(_suffix "-static")
        else()
            set(_suffix "-shared")
        endif()
        foreach(_lang ${HDF5_LANGUAGE_BINDINGS})
            get_target_property(_lang_location ${HDF5_${_component}_TARGET}${_suffix} LOCATION)
            if( _lang_location )
                set(HDF5_${_lang}_LIBRARY ${_lang_location} CACHE PATH
                    "HDF5 ${_lang} library" )
                mark_as_advanced(HDF5_${_lang}_LIBRARY)
                list(APPEND HDF5_LIBRARIES ${HDF5_${_lang}_LIBRARY})
            endif()
            if(FIND_HL)
                get_target_property(_lang_hl_location ${HDF5_${_lang}_HL_TARGET}${_suffix} LOCATION)
                if( _lang_location )
                    set(HDF5_${_lang}_HL_LIBRARY ${_lang_location} CACHE PATH
                        "HDF5 ${_lang} HL library" )
                    mark_as_advanced(HDF5_${_lang}_LIBRARY)
                    list(APPEND HDF5_HL_LIBRARIES ${HDF5_${_lang}_HL_LIBRARY})
                endif()
            endif()
        endforeach()
    endif()
endif()

if(NOT HDF5_FOUND AND NOT HDF5_ROOT)
  set(_HDF5_NEED_TO_SEARCH False)
  set(HDF5_COMPILER_NO_INTERROGATE True)
  # Only search for languages we've enabled
  foreach(__lang IN LISTS HDF5_LANGUAGE_BINDINGS)
    # First check to see if our regular compiler is one of wrappers
    if(__lang STREQUAL "C")
      _HDF5_test_regular_compiler_C(
        HDF5_${__lang}_COMPILER_NO_INTERROGATE
        HDF5_${__lang}_VERSION)
    elseif(__lang STREQUAL "CXX")
      _HDF5_test_regular_compiler_CXX(
        HDF5_${__lang}_COMPILER_NO_INTERROGATE
        HDF5_${__lang}_VERSION)
    elseif(__lang STREQUAL "Fortran")
      _HDF5_test_regular_compiler_Fortran(
        HDF5_${__lang}_COMPILER_NO_INTERROGATE)
    else()
      continue()
    endif()
    if(HDF5_${__lang}_COMPILER_NO_INTERROGATE)
      message(STATUS "HDF5: Using hdf5 compiler wrapper for all ${__lang} compiling")
      set(HDF5_${__lang}_FOUND True)
      set(HDF5_${__lang}_COMPILER_EXECUTABLE_NO_INTERROGATE
          "${CMAKE_${__lang}_COMPILER}"
          CACHE FILEPATH "HDF5 ${__lang} compiler wrapper")
      set(HDF5_${__lang}_DEFINITIONS)
      set(HDF5_${__lang}_INCLUDE_DIRS)
      set(HDF5_${__lang}_LIBRARIES)
      mark_as_advanced(HDF5_${__lang}_COMPILER_EXECUTABLE_NO_INTERROGATE)
      mark_as_advanced(HDF5_${__lang}_DEFINITIONS)
      mark_as_advanced(HDF5_${__lang}_INCLUDE_DIRS)
      mark_as_advanced(HDF5_${__lang}_LIBRARIES)
      mark_as_advanced(HDF5_${__lang}_HL_LIBRARIES)
    else()
      set(HDF5_COMPILER_NO_INTERROGATE False)
      # If this language isn't using the wrapper, then try to seed the
      # search options with the wrapper
      find_program(HDF5_${__lang}_COMPILER_EXECUTABLE
        NAMES ${HDF5_${__lang}_COMPILER_NAMES} NAMES_PER_DIR
        HINTS ENV HDF5_ROOT
        PATH_SUFFIXES bin Bin
        DOC "HDF5 ${__lang} Wrapper compiler.  Used only to detect HDF5 compile flags."
      )
      mark_as_advanced( HDF5_${__lang}_COMPILER_EXECUTABLE )
      unset(HDF5_${__lang}_COMPILER_NAMES)

      if(HDF5_${__lang}_COMPILER_EXECUTABLE)
        _HDF5_invoke_compiler(${__lang} HDF5_${__lang}_COMPILE_LINE
          HDF5_${__lang}_RETURN_VALUE HDF5_${__lang}_VERSION)
        if(HDF5_${__lang}_RETURN_VALUE EQUAL 0)
          message(STATUS "HDF5: Using hdf5 compiler wrapper to determine ${__lang} configuration")
          _HDF5_parse_compile_line( HDF5_${__lang}_COMPILE_LINE
            HDF5_${__lang}_INCLUDE_DIRS
            HDF5_${__lang}_DEFINITIONS
            HDF5_${__lang}_LIBRARY_DIRS
            HDF5_${__lang}_LIBRARY_NAMES
            HDF5_${__lang}_HL_LIBRARY_NAMES
          )
          set(HDF5_${__lang}_LIBRARIES)
          foreach(L IN LISTS HDF5_${__lang}_LIBRARY_NAMES)
            find_library(HDF5_${__lang}_LIBRARY_${L} ${L} ${HDF5_${__lang}_LIBRARY_DIRS})
            if(HDF5_${__lang}_LIBRARY_${L})
              list(APPEND HDF5_${__lang}_LIBRARIES ${HDF5_${__lang}_LIBRARY_${L}})
            else()
              list(APPEND HDF5_${__lang}_LIBRARIES ${L})
            endif()
          endforeach()
          if(FIND_HL)
            set(HDF5_${__lang}_HL_LIBRARIES)
            foreach(L IN LISTS HDF5_${__lang}_HL_LIBRARY_NAMES)
              find_library(HDF5_${__lang}_LIBRARY_${L} ${L} ${HDF5_${__lang}_LIBRARY_DIRS})
              if(HDF5_${__lang}_LIBRARY_${L})
                list(APPEND HDF5_${__lang}_HL_LIBRARIES ${HDF5_${__lang}_LIBRARY_${L}})
              else()
                list(APPEND HDF5_${__lang}_HL_LIBRARIES ${L})
              endif()
            endforeach()
          endif()
          set(HDF5_${__lang}_FOUND True)
          mark_as_advanced(HDF5_${__lang}_DEFINITIONS)
          mark_as_advanced(HDF5_${__lang}_INCLUDE_DIRS)
          mark_as_advanced(HDF5_${__lang}_LIBRARIES)
          _HDF5_remove_duplicates_from_beginning(HDF5_${__lang}_DEFINITIONS)
          _HDF5_remove_duplicates_from_beginning(HDF5_${__lang}_INCLUDE_DIRS)
          _HDF5_remove_duplicates_from_beginning(HDF5_${__lang}_LIBRARIES)
          _HDF5_remove_duplicates_from_beginning(HDF5_${__lang}_HL_LIBRARIES)
        else()
          set(_HDF5_NEED_TO_SEARCH True)
        endif()
      else()
        set(_HDF5_NEED_TO_SEARCH True)
      endif()
    endif()
    if(HDF5_${__lang}_VERSION)
      if(NOT HDF5_VERSION)
        set(HDF5_VERSION ${HDF5_${__lang}_VERSION})
      elseif(NOT HDF5_VERSION VERSION_EQUAL HDF5_${__lang}_VERSION)
        message(WARNING "HDF5 Version found for language ${__lang}, ${HDF5_${__lang}_VERSION} is different than previously found version ${HDF5_VERSION}")
      endif()
    endif()
  endforeach()
else()
  set(_HDF5_NEED_TO_SEARCH True)
endif()

if(NOT HDF5_FOUND AND HDF5_COMPILER_NO_INTERROGATE)
  # No arguments necessary, all languages can use the compiler wrappers
  set(HDF5_FOUND True)
  set(HDF5_METHOD "Included by compiler wrappers")
  set(HDF5_REQUIRED_VARS HDF5_METHOD)
elseif(NOT HDF5_FOUND AND NOT _HDF5_NEED_TO_SEARCH)
  # Compiler wrappers aren't being used by the build but were found and used
  # to determine necessary include and library flags
  set(HDF5_INCLUDE_DIRS)
  set(HDF5_LIBRARIES)
  set(HDF5_HL_LIBRARIES)
  foreach(__lang IN LISTS HDF5_LANGUAGE_BINDINGS)
    if(HDF5_${__lang}_FOUND)
      if(NOT HDF5_${__lang}_COMPILER_NO_INTERROGATE)
        list(APPEND HDF5_DEFINITIONS ${HDF5_${__lang}_DEFINITIONS})
        list(APPEND HDF5_INCLUDE_DIRS ${HDF5_${__lang}_INCLUDE_DIRS})
        list(APPEND HDF5_LIBRARIES ${HDF5_${__lang}_LIBRARIES})
        if(FIND_HL)
          list(APPEND HDF5_HL_LIBRARIES ${HDF5_${__lang}_HL_LIBRARIES})
        endif()
      endif()
    endif()
  endforeach()
  _HDF5_remove_duplicates_from_beginning(HDF5_DEFINITIONS)
  _HDF5_remove_duplicates_from_beginning(HDF5_INCLUDE_DIRS)
  _HDF5_remove_duplicates_from_beginning(HDF5_LIBRARIES)
  _HDF5_remove_duplicates_from_beginning(HDF5_HL_LIBRARIES)
  set(HDF5_FOUND True)
  set(HDF5_REQUIRED_VARS HDF5_LIBRARIES)
  if(FIND_HL)
    list(APPEND HDF5_REQUIRED_VARS HDF5_HL_LIBRARIES)
  endif()
endif()

find_program( HDF5_DIFF_EXECUTABLE
    NAMES h5diff
    HINTS ENV HDF5_ROOT
    PATH_SUFFIXES bin Bin
    DOC "HDF5 file differencing tool." )
mark_as_advanced( HDF5_DIFF_EXECUTABLE )

if( NOT HDF5_FOUND )
    # seed the initial lists of libraries to find with items we know we need
    set(HDF5_C_LIBRARY_NAMES          hdf5)
    set(HDF5_C_HL_LIBRARY_NAMES       hdf5_hl)

    set(HDF5_CXX_LIBRARY_NAMES        hdf5_cpp    ${HDF5_C_LIBRARY_NAMES})
    set(HDF5_CXX_HL_LIBRARY_NAMES     hdf5_hl_cpp ${HDF5_C_HL_LIBRARY_NAMES} ${HDF5_CXX_LIBRARY_NAMES})

    set(HDF5_Fortran_LIBRARY_NAMES    hdf5_fortran   ${HDF5_C_LIBRARY_NAMES})
    set(HDF5_Fortran_HL_LIBRARY_NAMES hdf5_hl_fortran ${HDF5_C_HL_LIBRARY_NAMES} ${HDF5_Fortran_LIBRARY_NAMES})

    if(HDF5_ROOT)
        set(SEARCH_OPTS NO_DEFAULT_PATH)
    endif()
    foreach(__lang IN LISTS HDF5_LANGUAGE_BINDINGS)
        # find the HDF5 include directories
        if(LANGUAGE STREQUAL "Fortran")
            set(HDF5_INCLUDE_FILENAME hdf5.mod)
        elseif(LANGUAGE STREQUAL "CXX")
            set(HDF5_INCLUDE_FILENAME H5Cpp.h)
        else()
            set(HDF5_INCLUDE_FILENAME hdf5.h)
        endif()

        find_path(HDF5_${__lang}_INCLUDE_DIR ${HDF5_INCLUDE_FILENAME}
            HINTS ${HDF5_ROOT} ENV HDF5_ROOT
            PATHS $ENV{HOME}/.local/include
            PATH_SUFFIXES include Include
            ${SEARCH_OPTS}
        )
        mark_as_advanced(HDF5_${LANGUAGE}_INCLUDE_DIR)
        list(APPEND HDF5_INCLUDE_DIRS ${HDF5_${__lang}_INCLUDE_DIR})

        # find the HDF5 libraries
        foreach(LIB IN LISTS HDF5_${__lang}_LIBRARY_NAMES)
            if(UNIX AND HDF5_USE_STATIC_LIBRARIES)
                # According to bug 1643 on the CMake bug tracker, this is the
                # preferred method for searching for a static library.
                # See https://cmake.org/Bug/view.php?id=1643.  We search
                # first for the full static library name, but fall back to a
                # generic search on the name if the static search fails.
                set( THIS_LIBRARY_SEARCH_DEBUG
                    lib${LIB}d.a lib${LIB}_debug.a ${LIB}d ${LIB}_debug
                    lib${LIB}d-static.a lib${LIB}_debug-static.a ${LIB}d-static ${LIB}_debug-static )
                set( THIS_LIBRARY_SEARCH_RELEASE lib${LIB}.a ${LIB} lib${LIB}-static.a ${LIB}-static)
            else()
                set( THIS_LIBRARY_SEARCH_DEBUG ${LIB}d ${LIB}_debug ${LIB}d-shared ${LIB}_debug-shared)
                set( THIS_LIBRARY_SEARCH_RELEASE ${LIB} ${LIB}-shared)
            endif()
            find_library(HDF5_${LIB}_LIBRARY_DEBUG
                NAMES ${THIS_LIBRARY_SEARCH_DEBUG}
                HINTS ${HDF5_ROOT} ENV HDF5_ROOT PATH_SUFFIXES lib Lib
                ${SEARCH_OPTS}
            )
            find_library( HDF5_${LIB}_LIBRARY_RELEASE
                NAMES ${THIS_LIBRARY_SEARCH_RELEASE}
                HINTS ${HDF5_ROOT} ENV HDF5_ROOT PATH_SUFFIXES lib Lib
                ${SEARCH_OPTS}
            )
            select_library_configurations( HDF5_${LIB} )
            list(APPEND HDF5_${__lang}_LIBRARIES ${HDF5_${LIB}_LIBRARY})
        eNdforeach()

        # Append the libraries for this language binding to the list of all
        # required libraries.
        list(APPEND HDF5_LIBRARIES ${HDF5_${__lang}_LIBRARIES})

        if(FIND_HL)
            foreach(LIB IN LISTS HDF5_${__lang}_HL_LIBRARY_NAMES)
                if(UNIX AND HDF5_USE_STATIC_LIBRARIES)
                    # According to bug 1643 on the CMake bug tracker, this is the
                    # preferred method for searching for a static library.
                    # See https://cmake.org/Bug/view.php?id=1643.  We search
                    # first for the full static library name, but fall back to a
                    # generic search on the name if the static search fails.
                    set( THIS_LIBRARY_SEARCH_DEBUG
                        lib${LIB}d.a lib${LIB}_debug.a ${LIB}d ${LIB}_debug
                        lib${LIB}d-static.a lib${LIB}_debug-static.a ${LIB}d-static ${LIB}_debug-static )
                    set( THIS_LIBRARY_SEARCH_RELEASE lib${LIB}.a ${LIB} lib${LIB}-static.a ${LIB}-static)
                else()
                    set( THIS_LIBRARY_SEARCH_DEBUG ${LIB}d ${LIB}_debug ${LIB}d-shared ${LIB}_debug-shared)
                    set( THIS_LIBRARY_SEARCH_RELEASE ${LIB} ${LIB}-shared)
                endif()
                find_library(HDF5_${LIB}_LIBRARY_DEBUG
                    NAMES ${THIS_LIBRARY_SEARCH_DEBUG}
                    HINTS ${HDF5_ROOT} ENV HDF5_ROOT PATH_SUFFIXES lib Lib
                    ${SEARCH_OPTS}
                )
                find_library( HDF5_${LIB}_LIBRARY_RELEASE
                    NAMES ${THIS_LIBRARY_SEARCH_RELEASE}
                    HINTS ${HDF5_ROOT} ENV HDF5_ROOT PATH_SUFFIXES lib Lib
                    ${SEARCH_OPTS}
                )
                select_library_configurations( HDF5_${LIB} )
                list(APPEND HDF5_${__lang}_HL_LIBRARIES ${HDF5_${LIB}_LIBRARY})
            endforeach()

            # Append the libraries for this language binding to the list of all
            # required libraries.
            list(APPEND HDF5_HL_LIBRARIES ${HDF5_${__lang}_HL_LIBRARIES})
        endif()
    endforeach()

    _HDF5_remove_duplicates_from_beginning(HDF5_INCLUDE_DIRS)
    _HDF5_remove_duplicates_from_beginning(HDF5_LIBRARIES)
    _HDF5_remove_duplicates_from_beginning(HDF5_HL_LIBRARIES)

    # If the HDF5 include directory was found, open H5pubconf.h to determine if
    # HDF5 was compiled with parallel IO support
    set( HDF5_IS_PARALLEL FALSE )
    set( HDF5_VERSION "" )
    foreach( _dir IN LISTS HDF5_INCLUDE_DIRS )
      foreach(_hdr "${_dir}/H5pubconf.h" "${_dir}/H5pubconf-64.h" "${_dir}/H5pubconf-32.h")
        if( EXISTS "${_hdr}" )
            file( STRINGS "${_hdr}"
                HDF5_HAVE_PARALLEL_DEFINE
                REGEX "HAVE_PARALLEL 1" )
            if( HDF5_HAVE_PARALLEL_DEFINE )
                set( HDF5_IS_PARALLEL TRUE )
            endif()
            unset(HDF5_HAVE_PARALLEL_DEFINE)

            file( STRINGS "${_hdr}"
                HDF5_VERSION_DEFINE
                REGEX "^[ \t]*#[ \t]*define[ \t]+H5_VERSION[ \t]+" )
            if( "${HDF5_VERSION_DEFINE}" MATCHES
                "H5_VERSION[ \t]+\"([0-9]+\\.[0-9]+\\.[0-9]+)(-patch([0-9]+))?\"" )
                set( HDF5_VERSION "${CMAKE_MATCH_1}" )
                if( CMAKE_MATCH_3 )
                  set( HDF5_VERSION ${HDF5_VERSION}.${CMAKE_MATCH_3})
                endif()
            endif()
            unset(HDF5_VERSION_DEFINE)
        endif()
      endforeach()
    endforeach()
    set( HDF5_IS_PARALLEL ${HDF5_IS_PARALLEL} CACHE BOOL
        "HDF5 library compiled with parallel IO support" )
    mark_as_advanced( HDF5_IS_PARALLEL )

    # For backwards compatibility we set HDF5_INCLUDE_DIR to the value of
    # HDF5_INCLUDE_DIRS
    if( HDF5_INCLUDE_DIRS )
        set( HDF5_INCLUDE_DIR "${HDF5_INCLUDE_DIRS}" )
    endif()
    set(HDF5_REQUIRED_VARS HDF5_LIBRARIES HDF5_INCLUDE_DIRS)
    if(FIND_HL)
        list(APPEND HDF5_REQUIRED_VARS HDF5_HL_LIBRARIES)
    endif()
endif()

# If HDF5_REQUIRED_VARS is empty at this point, then it's likely that
# something external is trying to explicitly pass already found
# locations
if(NOT HDF5_REQUIRED_VARS)
    set(HDF5_REQUIRED_VARS HDF5_LIBRARIES HDF5_INCLUDE_DIRS)
endif()

find_package_handle_standard_args(HDF5
    REQUIRED_VARS ${HDF5_REQUIRED_VARS}
    VERSION_VAR   HDF5_VERSION
)