CMake/Modules/FindBoost.cmake

# Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
# file Copyright.txt or https://cmake.org/licensing for details.

#[=======================================================================[.rst:
FindBoost
---------

Find Boost include dirs and libraries

Use this module by invoking find_package with the form::

  find_package(Boost
    [version] [EXACT]      # Minimum or EXACT version e.g. 1.67.0
    [REQUIRED]             # Fail with error if Boost is not found
    [COMPONENTS <libs>...] # Boost libraries by their canonical name
                           # e.g. "date_time" for "libboost_date_time"
    [OPTIONAL_COMPONENTS <libs>...]
                           # Optional Boost libraries by their canonical name)
    )                      # e.g. "date_time" for "libboost_date_time"

This module finds headers and requested component libraries OR a CMake
package configuration file provided by a "Boost CMake" build.  For the
latter case skip to the "Boost CMake" section below.  For the former
case results are reported in variables::

  Boost_FOUND            - True if headers and requested libraries were found
  Boost_INCLUDE_DIRS     - Boost include directories
  Boost_LIBRARY_DIRS     - Link directories for Boost libraries
  Boost_LIBRARIES        - Boost component libraries to be linked
  Boost_<C>_FOUND        - True if component <C> was found (<C> is upper-case)
  Boost_<C>_LIBRARY      - Libraries to link for component <C> (may include
                           target_link_libraries debug/optimized keywords)
  Boost_VERSION          - BOOST_VERSION value from boost/version.hpp
  Boost_LIB_VERSION      - Version string appended to library filenames
  Boost_MAJOR_VERSION    - Boost major version number (X in X.y.z)
  Boost_MINOR_VERSION    - Boost minor version number (Y in x.Y.z)
  Boost_SUBMINOR_VERSION - Boost subminor version number (Z in x.y.Z)
  Boost_VERSION_STRING   - Boost version number in x.y.z format
  Boost_LIB_DIAGNOSTIC_DEFINITIONS (Windows)
                         - Pass to add_definitions() to have diagnostic
                           information about Boost's automatic linking
                           displayed during compilation

Note that Boost Python components require a Python version suffix
(Boost 1.67 and later), e.g. ``python36`` or ``python27`` for the
versions built against Python 3.6 and 2.7, respectively.  This also
applies to additional components using Python including
``mpi_python`` and ``numpy``.  Earlier Boost releases may use
distribution-specific suffixes such as ``2``, ``3`` or ``2.7``.
These may also be used as suffixes, but note that they are not
portable.

This module reads hints about search locations from variables::

  BOOST_ROOT             - Preferred installation prefix
   (or BOOSTROOT)
  BOOST_INCLUDEDIR       - Preferred include directory e.g. <prefix>/include
  BOOST_LIBRARYDIR       - Preferred library directory e.g. <prefix>/lib
  Boost_NO_SYSTEM_PATHS  - Set to ON to disable searching in locations not
                           specified by these hint variables. Default is OFF.
  Boost_ADDITIONAL_VERSIONS
                         - List of Boost versions not known to this module
                           (Boost install locations may contain the version)

and saves search results persistently in CMake cache entries::

  Boost_INCLUDE_DIR         - Directory containing Boost headers
  Boost_LIBRARY_DIR_RELEASE - Directory containing release Boost libraries
  Boost_LIBRARY_DIR_DEBUG   - Directory containing debug Boost libraries
  Boost_<C>_LIBRARY_DEBUG   - Component <C> library debug variant
  Boost_<C>_LIBRARY_RELEASE - Component <C> library release variant

The following :prop_tgt:`IMPORTED` targets are also defined::

  Boost::boost                  - Target for header-only dependencies
                                  (Boost include directory)
  Boost::<C>                    - Target for specific component dependency
                                  (shared or static library); <C> is lower-
                                  case
  Boost::diagnostic_definitions - interface target to enable diagnostic
                                  information about Boost's automatic linking
                                  during compilation (adds BOOST_LIB_DIAGNOSTIC)
  Boost::disable_autolinking    - interface target to disable automatic
                                  linking with MSVC (adds BOOST_ALL_NO_LIB)
  Boost::dynamic_linking        - interface target to enable dynamic linking
                                  linking with MSVC (adds BOOST_ALL_DYN_LINK)

Implicit dependencies such as Boost::filesystem requiring
Boost::system will be automatically detected and satisfied, even
if system is not specified when using find_package and if
Boost::system is not added to target_link_libraries.  If using
Boost::thread, then Threads::Threads will also be added automatically.

It is important to note that the imported targets behave differently
than variables created by this module: multiple calls to
find_package(Boost) in the same directory or sub-directories with
different options (e.g. static or shared) will not override the
values of the targets created by the first call.

Users may set these hints or results as cache entries.  Projects
should not read these entries directly but instead use the above
result variables.  Note that some hint names start in upper-case
"BOOST".  One may specify these as environment variables if they are
not specified as CMake variables or cache entries.

This module first searches for the Boost header files using the above
hint variables (excluding BOOST_LIBRARYDIR) and saves the result in
Boost_INCLUDE_DIR.  Then it searches for requested component libraries
using the above hints (excluding BOOST_INCLUDEDIR and
Boost_ADDITIONAL_VERSIONS), "lib" directories near Boost_INCLUDE_DIR,
and the library name configuration settings below.  It saves the
library directories in Boost_LIBRARY_DIR_DEBUG and
Boost_LIBRARY_DIR_RELEASE and individual library
locations in Boost_<C>_LIBRARY_DEBUG and Boost_<C>_LIBRARY_RELEASE.
When one changes settings used by previous searches in the same build
tree (excluding environment variables) this module discards previous
search results affected by the changes and searches again.

Boost libraries come in many variants encoded in their file name.
Users or projects may tell this module which variant to find by
setting variables::

  Boost_USE_DEBUG_LIBS     - Set to ON or OFF to specify whether to search
                             and use the debug libraries.  Default is ON.
  Boost_USE_RELEASE_LIBS   - Set to ON or OFF to specify whether to search
                             and use the release libraries.  Default is ON.
  Boost_USE_MULTITHREADED  - Set to OFF to use the non-multithreaded
                             libraries ('mt' tag).  Default is ON.
  Boost_USE_STATIC_LIBS    - Set to ON to force the use of the static
                             libraries.  Default is OFF.
  Boost_USE_STATIC_RUNTIME - Set to ON or OFF to specify whether to use
                             libraries linked statically to the C++ runtime
                             ('s' tag).  Default is platform dependent.
  Boost_USE_DEBUG_RUNTIME  - Set to ON or OFF to specify whether to use
                             libraries linked to the MS debug C++ runtime
                             ('g' tag).  Default is ON.
  Boost_USE_DEBUG_PYTHON   - Set to ON to use libraries compiled with a
                             debug Python build ('y' tag). Default is OFF.
  Boost_USE_STLPORT        - Set to ON to use libraries compiled with
                             STLPort ('p' tag).  Default is OFF.
  Boost_USE_STLPORT_DEPRECATED_NATIVE_IOSTREAMS
                           - Set to ON to use libraries compiled with
                             STLPort deprecated "native iostreams"
                             ('n' tag).  Default is OFF.
  Boost_COMPILER           - Set to the compiler-specific library suffix
                             (e.g. "-gcc43").  Default is auto-computed
                             for the C++ compiler in use.  A list may be
                             used if multiple compatible suffixes should
                             be tested for, in decreasing order of
                             preference.
  Boost_ARCHITECTURE       - Set to the architecture-specific library suffix
                             (e.g. "-x64").  Default is auto-computed for the
                             C++ compiler in use.
  Boost_THREADAPI          - Suffix for "thread" component library name,
                             such as "pthread" or "win32".  Names with
                             and without this suffix will both be tried.
  Boost_NAMESPACE          - Alternate namespace used to build boost with
                             e.g. if set to "myboost", will search for
                             myboost_thread instead of boost_thread.

Other variables one may set to control this module are::

  Boost_DEBUG              - Set to ON to enable debug output from FindBoost.
                             Please enable this before filing any bug report.
  Boost_DETAILED_FAILURE_MSG
                           - Set to ON to add detailed information to the
                             failure message even when the REQUIRED option
                             is not given to the find_package call.
  Boost_REALPATH           - Set to ON to resolve symlinks for discovered
                             libraries to assist with packaging.  For example,
                             the "system" component library may be resolved to
                             "/usr/lib/libboost_system.so.1.67.0" instead of
                             "/usr/lib/libboost_system.so".  This does not
                             affect linking and should not be enabled unless
                             the user needs this information.
  Boost_LIBRARY_DIR        - Default value for Boost_LIBRARY_DIR_RELEASE and
                             Boost_LIBRARY_DIR_DEBUG.

On Visual Studio and Borland compilers Boost headers request automatic
linking to corresponding libraries.  This requires matching libraries
to be linked explicitly or available in the link library search path.
In this case setting Boost_USE_STATIC_LIBS to OFF may not achieve
dynamic linking.  Boost automatic linking typically requests static
libraries with a few exceptions (such as Boost.Python).  Use::

  add_definitions(${Boost_LIB_DIAGNOSTIC_DEFINITIONS})

to ask Boost to report information about automatic linking requests.

Example to find Boost headers only::

  find_package(Boost 1.36.0)
  if(Boost_FOUND)
    include_directories(${Boost_INCLUDE_DIRS})
    add_executable(foo foo.cc)
  endif()

Example to find Boost libraries and use imported targets::

  find_package(Boost 1.56 REQUIRED COMPONENTS
               date_time filesystem iostreams)
  add_executable(foo foo.cc)
  target_link_libraries(foo Boost::date_time Boost::filesystem
                            Boost::iostreams)

Example to find Boost Python 3.6 libraries and use imported targets::

  find_package(Boost 1.67 REQUIRED COMPONENTS
               python36 numpy36)
  add_executable(foo foo.cc)
  target_link_libraries(foo Boost::python36 Boost::numpy36)

Example to find Boost headers and some *static* (release only) libraries::

  set(Boost_USE_STATIC_LIBS        ON)  # only find static libs
  set(Boost_USE_DEBUG_LIBS         OFF) # ignore debug libs and
  set(Boost_USE_RELEASE_LIBS       ON)  # only find release libs
  set(Boost_USE_MULTITHREADED      ON)
  set(Boost_USE_STATIC_RUNTIME    OFF)
  find_package(Boost 1.66.0 COMPONENTS date_time filesystem system ...)
  if(Boost_FOUND)
    include_directories(${Boost_INCLUDE_DIRS})
    add_executable(foo foo.cc)
    target_link_libraries(foo ${Boost_LIBRARIES})
  endif()

Boost CMake
^^^^^^^^^^^

If Boost was built using the boost-cmake project it provides a package
configuration file for use with find_package's Config mode.  This
module looks for the package configuration file called
BoostConfig.cmake or boost-config.cmake and stores the result in cache
entry "Boost_DIR".  If found, the package configuration file is loaded
and this module returns with no further action.  See documentation of
the Boost CMake package configuration for details on what it provides.

Set Boost_NO_BOOST_CMAKE to ON to disable the search for boost-cmake.
#]=======================================================================]

# Save project's policies
cmake_policy(PUSH)
cmake_policy(SET CMP0057 NEW) # if IN_LIST

#-------------------------------------------------------------------------------
# Before we go searching, check whether boost-cmake is available, unless the
# user specifically asked NOT to search for boost-cmake.
#
# If Boost_DIR is set, this behaves as any find_package call would. If not,
# it looks at BOOST_ROOT and BOOSTROOT to find Boost.
#
if (NOT Boost_NO_BOOST_CMAKE)
  # If Boost_DIR is not set, look for BOOSTROOT and BOOST_ROOT as alternatives,
  # since these are more conventional for Boost.
  if ("$ENV{Boost_DIR}" STREQUAL "")
    if (NOT "$ENV{BOOST_ROOT}" STREQUAL "")
      set(ENV{Boost_DIR} $ENV{BOOST_ROOT})
    elseif (NOT "$ENV{BOOSTROOT}" STREQUAL "")
      set(ENV{Boost_DIR} $ENV{BOOSTROOT})
    endif()
  endif()

  # Do the same find_package call but look specifically for the CMake version.
  # Note that args are passed in the Boost_FIND_xxxxx variables, so there is no
  # need to delegate them to this find_package call.
  find_package(Boost QUIET NO_MODULE)
  mark_as_advanced(Boost_DIR)

  # If we found boost-cmake, then we're done.  Print out what we found.
  # Otherwise let the rest of the module try to find it.
  if (Boost_FOUND)
    message(STATUS "Boost ${Boost_FIND_VERSION} found.")
    if (Boost_FIND_COMPONENTS)
      message(STATUS "Found Boost components:\n   ${Boost_FIND_COMPONENTS}")
    endif()
    # Restore project's policies
    cmake_policy(POP)
    return()
  endif()
endif()


#-------------------------------------------------------------------------------
#  FindBoost functions & macros
#

############################################
#
# Check the existence of the libraries.
#
############################################
# This macro was taken directly from the FindQt4.cmake file that is included
# with the CMake distribution. This is NOT my work. All work was done by the
# original authors of the FindQt4.cmake file. Only minor modifications were
# made to remove references to Qt and make this file more generally applicable
# And ELSE/ENDIF pairs were removed for readability.
#########################################################################

macro(_Boost_ADJUST_LIB_VARS basename)
  if(Boost_INCLUDE_DIR )
    if(Boost_${basename}_LIBRARY_DEBUG AND Boost_${basename}_LIBRARY_RELEASE)
      # if the generator is multi-config or if CMAKE_BUILD_TYPE is set for
      # single-config generators, set optimized and debug libraries
      get_property(_isMultiConfig GLOBAL PROPERTY GENERATOR_IS_MULTI_CONFIG)
      if(_isMultiConfig OR CMAKE_BUILD_TYPE)
        set(Boost_${basename}_LIBRARY optimized ${Boost_${basename}_LIBRARY_RELEASE} debug ${Boost_${basename}_LIBRARY_DEBUG})
      else()
        # For single-config generators where CMAKE_BUILD_TYPE has no value,
        # just use the release libraries
        set(Boost_${basename}_LIBRARY ${Boost_${basename}_LIBRARY_RELEASE} )
      endif()
      # FIXME: This probably should be set for both cases
      set(Boost_${basename}_LIBRARIES optimized ${Boost_${basename}_LIBRARY_RELEASE} debug ${Boost_${basename}_LIBRARY_DEBUG})
    endif()

    # if only the release version was found, set the debug variable also to the release version
    if(Boost_${basename}_LIBRARY_RELEASE AND NOT Boost_${basename}_LIBRARY_DEBUG)
      set(Boost_${basename}_LIBRARY_DEBUG ${Boost_${basename}_LIBRARY_RELEASE})
      set(Boost_${basename}_LIBRARY       ${Boost_${basename}_LIBRARY_RELEASE})
      set(Boost_${basename}_LIBRARIES     ${Boost_${basename}_LIBRARY_RELEASE})
    endif()

    # if only the debug version was found, set the release variable also to the debug version
    if(Boost_${basename}_LIBRARY_DEBUG AND NOT Boost_${basename}_LIBRARY_RELEASE)
      set(Boost_${basename}_LIBRARY_RELEASE ${Boost_${basename}_LIBRARY_DEBUG})
      set(Boost_${basename}_LIBRARY         ${Boost_${basename}_LIBRARY_DEBUG})
      set(Boost_${basename}_LIBRARIES       ${Boost_${basename}_LIBRARY_DEBUG})
    endif()

    # If the debug & release library ends up being the same, omit the keywords
    if("${Boost_${basename}_LIBRARY_RELEASE}" STREQUAL "${Boost_${basename}_LIBRARY_DEBUG}")
      set(Boost_${basename}_LIBRARY   ${Boost_${basename}_LIBRARY_RELEASE} )
      set(Boost_${basename}_LIBRARIES ${Boost_${basename}_LIBRARY_RELEASE} )
    endif()

    if(Boost_${basename}_LIBRARY AND Boost_${basename}_HEADER)
      set(Boost_${basename}_FOUND ON)
      if("x${basename}" STREQUAL "xTHREAD" AND NOT TARGET Threads::Threads)
        string(APPEND Boost_ERROR_REASON_THREAD " (missing dependency: Threads)")
        set(Boost_THREAD_FOUND OFF)
      endif()
    endif()

  endif()
  # Make variables changeable to the advanced user
  mark_as_advanced(
      Boost_${basename}_LIBRARY_RELEASE
      Boost_${basename}_LIBRARY_DEBUG
  )
endmacro()

# Detect changes in used variables.
# Compares the current variable value with the last one.
# In short form:
# v != v_LAST                      -> CHANGED = 1
# v is defined, v_LAST not         -> CHANGED = 1
# v is not defined, but v_LAST is  -> CHANGED = 1
# otherwise                        -> CHANGED = 0
# CHANGED is returned in variable named ${changed_var}
macro(_Boost_CHANGE_DETECT changed_var)
  set(${changed_var} 0)
  foreach(v ${ARGN})
    if(DEFINED _Boost_COMPONENTS_SEARCHED)
      if(${v})
        if(_${v}_LAST)
          string(COMPARE NOTEQUAL "${${v}}" "${_${v}_LAST}" _${v}_CHANGED)
        else()
          set(_${v}_CHANGED 1)
        endif()
      elseif(_${v}_LAST)
        set(_${v}_CHANGED 1)
      endif()
      if(_${v}_CHANGED)
        set(${changed_var} 1)
      endif()
    else()
      set(_${v}_CHANGED 0)
    endif()
  endforeach()
endmacro()

#
# Find the given library (var).
# Use 'build_type' to support different lib paths for RELEASE or DEBUG builds
#
macro(_Boost_FIND_LIBRARY var build_type)

  find_library(${var} ${ARGN})

  if(${var})
    # If this is the first library found then save Boost_LIBRARY_DIR_[RELEASE,DEBUG].
    if(NOT Boost_LIBRARY_DIR_${build_type})
      get_filename_component(_dir "${${var}}" PATH)
      set(Boost_LIBRARY_DIR_${build_type} "${_dir}" CACHE PATH "Boost library directory ${build_type}" FORCE)
    endif()
  elseif(_Boost_FIND_LIBRARY_HINTS_FOR_COMPONENT)
    # Try component-specific hints but do not save Boost_LIBRARY_DIR_[RELEASE,DEBUG].
    find_library(${var} HINTS ${_Boost_FIND_LIBRARY_HINTS_FOR_COMPONENT} ${ARGN})
  endif()

  # If Boost_LIBRARY_DIR_[RELEASE,DEBUG] is known then search only there.
  if(Boost_LIBRARY_DIR_${build_type})
    set(_boost_LIBRARY_SEARCH_DIRS_${build_type} ${Boost_LIBRARY_DIR_${build_type}} NO_DEFAULT_PATH NO_CMAKE_FIND_ROOT_PATH)
    if(Boost_DEBUG)
      message(STATUS "[ ${CMAKE_CURRENT_LIST_FILE}:${CMAKE_CURRENT_LIST_LINE} ] "
        " Boost_LIBRARY_DIR_${build_type} = ${Boost_LIBRARY_DIR_${build_type}}"
        " _boost_LIBRARY_SEARCH_DIRS_${build_type} = ${_boost_LIBRARY_SEARCH_DIRS_${build_type}}")
    endif()
  endif()
endmacro()

#-------------------------------------------------------------------------------

# Convert CMAKE_CXX_COMPILER_VERSION to boost compiler suffix version.
function(_Boost_COMPILER_DUMPVERSION _OUTPUT_VERSION _OUTPUT_VERSION_MAJOR _OUTPUT_VERSION_MINOR)
  string(REGEX REPLACE "([0-9]+)\\.([0-9]+)(\\.[0-9]+)?" "\\1"
    _boost_COMPILER_VERSION_MAJOR "${CMAKE_CXX_COMPILER_VERSION}")
  string(REGEX REPLACE "([0-9]+)\\.([0-9]+)(\\.[0-9]+)?" "\\2"
    _boost_COMPILER_VERSION_MINOR "${CMAKE_CXX_COMPILER_VERSION}")

  set(_boost_COMPILER_VERSION "${_boost_COMPILER_VERSION_MAJOR}${_boost_COMPILER_VERSION_MINOR}")

  set(${_OUTPUT_VERSION} ${_boost_COMPILER_VERSION} PARENT_SCOPE)
  set(${_OUTPUT_VERSION_MAJOR} ${_boost_COMPILER_VERSION_MAJOR} PARENT_SCOPE)
  set(${_OUTPUT_VERSION_MINOR} ${_boost_COMPILER_VERSION_MINOR} PARENT_SCOPE)
endfunction()

#
# Take a list of libraries with "thread" in it
# and prepend duplicates with "thread_${Boost_THREADAPI}"
# at the front of the list
#
function(_Boost_PREPEND_LIST_WITH_THREADAPI _output)
  set(_orig_libnames ${ARGN})
  string(REPLACE "thread" "thread_${Boost_THREADAPI}" _threadapi_libnames "${_orig_libnames}")
  set(${_output} ${_threadapi_libnames} ${_orig_libnames} PARENT_SCOPE)
endfunction()

#
# If a library is found, replace its cache entry with its REALPATH
#
function(_Boost_SWAP_WITH_REALPATH _library _docstring)
  if(${_library})
    get_filename_component(_boost_filepathreal ${${_library}} REALPATH)
    unset(${_library} CACHE)
    set(${_library} ${_boost_filepathreal} CACHE FILEPATH "${_docstring}")
  endif()
endfunction()

function(_Boost_CHECK_SPELLING _var)
  if(${_var})
    string(TOUPPER ${_var} _var_UC)
    message(FATAL_ERROR "ERROR: ${_var} is not the correct spelling.  The proper spelling is ${_var_UC}.")
  endif()
endfunction()

# Guesses Boost's compiler prefix used in built library names
# Returns the guess by setting the variable pointed to by _ret
function(_Boost_GUESS_COMPILER_PREFIX _ret)
  if("x${CMAKE_CXX_COMPILER_ID}" STREQUAL "xIntel")
    if(WIN32)
      set (_boost_COMPILER "-iw")
    else()
      set (_boost_COMPILER "-il")
    endif()
  elseif (GHSMULTI)
    set(_boost_COMPILER "-ghs")
  elseif("x${CMAKE_CXX_COMPILER_ID}" STREQUAL "xMSVC")
    if(MSVC_TOOLSET_VERSION GREATER_EQUAL 141)
      set(_boost_COMPILER "-vc141;-vc140")
    elseif(MSVC_TOOLSET_VERSION GREATER_EQUAL 80)
      set(_boost_COMPILER "-vc${MSVC_TOOLSET_VERSION}")
    elseif(NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 13.10)
      set(_boost_COMPILER "-vc71")
    elseif(NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 13) # Good luck!
      set(_boost_COMPILER "-vc7") # yes, this is correct
    else() # VS 6.0 Good luck!
      set(_boost_COMPILER "-vc6") # yes, this is correct
    endif()
  elseif (BORLAND)
    set(_boost_COMPILER "-bcb")
  elseif(CMAKE_CXX_COMPILER_ID STREQUAL "SunPro")
    set(_boost_COMPILER "-sw")
  elseif(CMAKE_CXX_COMPILER_ID STREQUAL "XL")
    set(_boost_COMPILER "-xlc")
  elseif (MINGW)
    if(${Boost_MAJOR_VERSION}.${Boost_MINOR_VERSION} VERSION_LESS 1.34)
        set(_boost_COMPILER "-mgw") # no GCC version encoding prior to 1.34
    else()
      _Boost_COMPILER_DUMPVERSION(_boost_COMPILER_VERSION _boost_COMPILER_VERSION_MAJOR _boost_COMPILER_VERSION_MINOR)
      set(_boost_COMPILER "-mgw${_boost_COMPILER_VERSION}")
    endif()
  elseif (UNIX)
    _Boost_COMPILER_DUMPVERSION(_boost_COMPILER_VERSION _boost_COMPILER_VERSION_MAJOR _boost_COMPILER_VERSION_MINOR)
    if(NOT Boost_VERSION VERSION_LESS 106900)
      # From GCC 5 and clang 4, versioning changes and minor becomes patch.
      # For those compilers, patch is exclude from compiler tag in Boost 1.69+ library naming.
      if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU" AND _boost_COMPILER_VERSION_MAJOR VERSION_GREATER 4)
        set(_boost_COMPILER_VERSION "${_boost_COMPILER_VERSION_MAJOR}")
      elseif(CMAKE_CXX_COMPILER_ID STREQUAL "Clang" AND _boost_COMPILER_VERSION_MAJOR VERSION_GREATER 3)
        set(_boost_COMPILER_VERSION "${_boost_COMPILER_VERSION_MAJOR}")
      endif()
    endif()

    if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
      if(${Boost_MAJOR_VERSION}.${Boost_MINOR_VERSION} VERSION_LESS 1.34)
        set(_boost_COMPILER "-gcc") # no GCC version encoding prior to 1.34
      else()
        # Determine which version of GCC we have.
        if(APPLE)
          if(Boost_MINOR_VERSION)
            if(${Boost_MINOR_VERSION} GREATER 35)
              # In Boost 1.36.0 and newer, the mangled compiler name used
              # on macOS/Darwin is "xgcc".
              set(_boost_COMPILER "-xgcc${_boost_COMPILER_VERSION}")
            else()
              # In Boost <= 1.35.0, there is no mangled compiler name for
              # the macOS/Darwin version of GCC.
              set(_boost_COMPILER "")
            endif()
          else()
            # We don't know the Boost version, so assume it's
            # pre-1.36.0.
            set(_boost_COMPILER "")
          endif()
        else()
          set(_boost_COMPILER "-gcc${_boost_COMPILER_VERSION}")
        endif()
      endif()
    elseif(CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
      # TODO: Find out any Boost version constraints vs clang support.
      set(_boost_COMPILER "-clang${_boost_COMPILER_VERSION}")
    endif()
  else()
    # TODO at least Boost_DEBUG here?
    set(_boost_COMPILER "")
  endif()
  set(${_ret} ${_boost_COMPILER} PARENT_SCOPE)
endfunction()

#
# Get component dependencies.  Requires the dependencies to have been
# defined for the Boost release version.
#
# component - the component to check
# _ret - list of library dependencies
#
function(_Boost_COMPONENT_DEPENDENCIES component _ret)
  # Note: to add a new Boost release, run
  #
  #   % cmake -DBOOST_DIR=/path/to/boost/source -P Utilities/Scripts/BoostScanDeps.cmake
  #
  # The output may be added in a new block below.  If it's the same as
  # the previous release, simply update the version range of the block
  # for the previous release.  Also check if any new components have
  # been added, and add any new components to
  # _Boost_COMPONENT_HEADERS.
  #
  # This information was originally generated by running
  # BoostScanDeps.cmake against every boost release to date supported
  # by FindBoost:
  #
  #   % for version in /path/to/boost/sources/*
  #     do
  #       cmake -DBOOST_DIR=$version -P Utilities/Scripts/BoostScanDeps.cmake
  #     done
  #
  # The output was then updated by search and replace with these regexes:
  #
  # - Strip message(STATUS) prefix dashes
  #   s;^-- ;;
  # - Indent
  #   s;^set(;    set(;;
  # - Add conditionals
  #   s;Scanning /path/to/boost/sources/boost_\(.*\)_\(.*\)_\(.*);  elseif(NOT Boost_VERSION VERSION_LESS \10\20\3 AND Boost_VERSION VERSION_LESS xxxx);
  #
  # This results in the logic seen below, but will require the xxxx
  # replacing with the following Boost release version (or the next
  # minor version to be released, e.g. 1.59 was the latest at the time
  # of writing, making 1.60 the next, so 106000 is the needed version
  # number).  Identical consecutive releases were then merged together
  # by updating the end range of the first block and removing the
  # following redundant blocks.
  #
  # Running the script against all historical releases should be
  # required only if the BoostScanDeps.cmake script logic is changed.
  # The addition of a new release should only require it to be run
  # against the new release.

  # Handle Python version suffixes
  if(component MATCHES "^(python|mpi_python|numpy)([0-9][0-9]?|[0-9]\\.[0-9])\$")
    set(component "${CMAKE_MATCH_1}")
    set(component_python_version "${CMAKE_MATCH_2}")
  endif()

  set(_Boost_IMPORTED_TARGETS TRUE)
  if(Boost_VERSION AND Boost_VERSION VERSION_LESS 103300)
    message(WARNING "Imported targets and dependency information not available for Boost version ${Boost_VERSION} (all versions older than 1.33)")
    set(_Boost_IMPORTED_TARGETS FALSE)
  elseif(NOT Boost_VERSION VERSION_LESS 103300 AND Boost_VERSION VERSION_LESS 103500)
    set(_Boost_IOSTREAMS_DEPENDENCIES regex thread)
    set(_Boost_REGEX_DEPENDENCIES thread)
    set(_Boost_WAVE_DEPENDENCIES filesystem thread)
    set(_Boost_WSERIALIZATION_DEPENDENCIES serialization)
  elseif(NOT Boost_VERSION VERSION_LESS 103500 AND Boost_VERSION VERSION_LESS 103600)
    set(_Boost_FILESYSTEM_DEPENDENCIES system)
    set(_Boost_IOSTREAMS_DEPENDENCIES regex)
    set(_Boost_MPI_DEPENDENCIES serialization)
    set(_Boost_MPI_PYTHON_DEPENDENCIES python${component_python_version} mpi serialization)
    set(_Boost_WAVE_DEPENDENCIES filesystem system thread)
    set(_Boost_WSERIALIZATION_DEPENDENCIES serialization)
  elseif(NOT Boost_VERSION VERSION_LESS 103600 AND Boost_VERSION VERSION_LESS 103800)
    set(_Boost_FILESYSTEM_DEPENDENCIES system)
    set(_Boost_IOSTREAMS_DEPENDENCIES regex)
    set(_Boost_MATH_DEPENDENCIES math_c99 math_c99f math_c99l math_tr1 math_tr1f math_tr1l)
    set(_Boost_MPI_DEPENDENCIES serialization)
    set(_Boost_MPI_PYTHON_DEPENDENCIES python${component_python_version} mpi serialization)
    set(_Boost_WAVE_DEPENDENCIES filesystem system thread)
    set(_Boost_WSERIALIZATION_DEPENDENCIES serialization)
  elseif(NOT Boost_VERSION VERSION_LESS 103800 AND Boost_VERSION VERSION_LESS 104300)
    set(_Boost_FILESYSTEM_DEPENDENCIES system)
    set(_Boost_IOSTREAMS_DEPENDENCIES regex)
    set(_Boost_MATH_DEPENDENCIES math_c99 math_c99f math_c99l math_tr1 math_tr1f math_tr1l)
    set(_Boost_MPI_DEPENDENCIES serialization)
    set(_Boost_MPI_PYTHON_DEPENDENCIES python${component_python_version} mpi serialization)
    set(_Boost_THREAD_DEPENDENCIES date_time)
    set(_Boost_WAVE_DEPENDENCIES filesystem system thread date_time)
    set(_Boost_WSERIALIZATION_DEPENDENCIES serialization)
  elseif(NOT Boost_VERSION VERSION_LESS 104300 AND Boost_VERSION VERSION_LESS 104400)
    set(_Boost_FILESYSTEM_DEPENDENCIES system)
    set(_Boost_IOSTREAMS_DEPENDENCIES regex)
    set(_Boost_MATH_DEPENDENCIES math_c99 math_c99f math_c99l math_tr1 math_tr1f math_tr1l random)
    set(_Boost_MPI_DEPENDENCIES serialization)
    set(_Boost_MPI_PYTHON_DEPENDENCIES python${component_python_version} mpi serialization)
    set(_Boost_THREAD_DEPENDENCIES date_time)
    set(_Boost_WAVE_DEPENDENCIES filesystem system thread date_time)
    set(_Boost_WSERIALIZATION_DEPENDENCIES serialization)
  elseif(NOT Boost_VERSION VERSION_LESS 104400 AND Boost_VERSION VERSION_LESS 104500)
    set(_Boost_FILESYSTEM_DEPENDENCIES system)
    set(_Boost_IOSTREAMS_DEPENDENCIES regex)
    set(_Boost_MATH_DEPENDENCIES math_c99 math_c99f math_c99l math_tr1 math_tr1f math_tr1l random serialization)
    set(_Boost_MPI_DEPENDENCIES serialization)
    set(_Boost_MPI_PYTHON_DEPENDENCIES python${component_python_version} mpi serialization)
    set(_Boost_THREAD_DEPENDENCIES date_time)
    set(_Boost_WAVE_DEPENDENCIES serialization filesystem system thread date_time)
    set(_Boost_WSERIALIZATION_DEPENDENCIES serialization)
  elseif(NOT Boost_VERSION VERSION_LESS 104500 AND Boost_VERSION VERSION_LESS 104700)
    set(_Boost_FILESYSTEM_DEPENDENCIES system)
    set(_Boost_IOSTREAMS_DEPENDENCIES regex)
    set(_Boost_MATH_DEPENDENCIES math_c99 math_c99f math_c99l math_tr1 math_tr1f math_tr1l random)
    set(_Boost_MPI_DEPENDENCIES serialization)
    set(_Boost_MPI_PYTHON_DEPENDENCIES python${component_python_version} mpi serialization)
    set(_Boost_THREAD_DEPENDENCIES date_time)
    set(_Boost_WAVE_DEPENDENCIES filesystem system serialization thread date_time)
    set(_Boost_WSERIALIZATION_DEPENDENCIES serialization)
  elseif(NOT Boost_VERSION VERSION_LESS 104700 AND Boost_VERSION VERSION_LESS 104800)
    set(_Boost_CHRONO_DEPENDENCIES system)
    set(_Boost_FILESYSTEM_DEPENDENCIES system)
    set(_Boost_IOSTREAMS_DEPENDENCIES regex)
    set(_Boost_MATH_DEPENDENCIES math_c99 math_c99f math_c99l math_tr1 math_tr1f math_tr1l random)
    set(_Boost_MPI_DEPENDENCIES serialization)
    set(_Boost_MPI_PYTHON_DEPENDENCIES python${component_python_version} mpi serialization)
    set(_Boost_THREAD_DEPENDENCIES date_time)
    set(_Boost_WAVE_DEPENDENCIES filesystem system serialization thread date_time)
    set(_Boost_WSERIALIZATION_DEPENDENCIES serialization)
  elseif(NOT Boost_VERSION VERSION_LESS 104800 AND Boost_VERSION VERSION_LESS 105000)
    set(_Boost_CHRONO_DEPENDENCIES system)
    set(_Boost_FILESYSTEM_DEPENDENCIES system)
    set(_Boost_IOSTREAMS_DEPENDENCIES regex)
    set(_Boost_MATH_DEPENDENCIES math_c99 math_c99f math_c99l math_tr1 math_tr1f math_tr1l random)
    set(_Boost_MPI_DEPENDENCIES serialization)
    set(_Boost_MPI_PYTHON_DEPENDENCIES python${component_python_version} mpi serialization)
    set(_Boost_THREAD_DEPENDENCIES date_time)
    set(_Boost_TIMER_DEPENDENCIES chrono system)
    set(_Boost_WAVE_DEPENDENCIES filesystem system serialization thread date_time)
    set(_Boost_WSERIALIZATION_DEPENDENCIES serialization)
  elseif(NOT Boost_VERSION VERSION_LESS 105000 AND Boost_VERSION VERSION_LESS 105300)
    set(_Boost_CHRONO_DEPENDENCIES system)
    set(_Boost_FILESYSTEM_DEPENDENCIES system)
    set(_Boost_IOSTREAMS_DEPENDENCIES regex)
    set(_Boost_MATH_DEPENDENCIES math_c99 math_c99f math_c99l math_tr1 math_tr1f math_tr1l regex random)
    set(_Boost_MPI_DEPENDENCIES serialization)
    set(_Boost_MPI_PYTHON_DEPENDENCIES python${component_python_version} mpi serialization)
    set(_Boost_THREAD_DEPENDENCIES chrono system date_time)
    set(_Boost_TIMER_DEPENDENCIES chrono system)
    set(_Boost_WAVE_DEPENDENCIES filesystem system serialization thread chrono date_time)
    set(_Boost_WSERIALIZATION_DEPENDENCIES serialization)
  elseif(NOT Boost_VERSION VERSION_LESS 105300 AND Boost_VERSION VERSION_LESS 105400)
    set(_Boost_ATOMIC_DEPENDENCIES thread chrono system date_time)
    set(_Boost_CHRONO_DEPENDENCIES system)
    set(_Boost_FILESYSTEM_DEPENDENCIES system)
    set(_Boost_IOSTREAMS_DEPENDENCIES regex)
    set(_Boost_MATH_DEPENDENCIES math_c99 math_c99f math_c99l math_tr1 math_tr1f math_tr1l regex random)
    set(_Boost_MPI_DEPENDENCIES serialization)
    set(_Boost_MPI_PYTHON_DEPENDENCIES python${component_python_version} mpi serialization)
    set(_Boost_THREAD_DEPENDENCIES chrono system date_time atomic)
    set(_Boost_TIMER_DEPENDENCIES chrono system)
    set(_Boost_WAVE_DEPENDENCIES filesystem system serialization thread chrono date_time)
    set(_Boost_WSERIALIZATION_DEPENDENCIES serialization)
  elseif(NOT Boost_VERSION VERSION_LESS 105400 AND Boost_VERSION VERSION_LESS 105500)
    set(_Boost_ATOMIC_DEPENDENCIES thread chrono system date_time)
    set(_Boost_CHRONO_DEPENDENCIES system)
    set(_Boost_FILESYSTEM_DEPENDENCIES system)
    set(_Boost_IOSTREAMS_DEPENDENCIES regex)
    set(_Boost_LOG_DEPENDENCIES log_setup date_time system filesystem thread regex chrono)
    set(_Boost_MATH_DEPENDENCIES math_c99 math_c99f math_c99l math_tr1 math_tr1f math_tr1l regex random)
    set(_Boost_MPI_DEPENDENCIES serialization)
    set(_Boost_MPI_PYTHON_DEPENDENCIES python${component_python_version} mpi serialization)
    set(_Boost_THREAD_DEPENDENCIES chrono system date_time atomic)
    set(_Boost_TIMER_DEPENDENCIES chrono system)
    set(_Boost_WAVE_DEPENDENCIES filesystem system serialization thread chrono date_time atomic)
    set(_Boost_WSERIALIZATION_DEPENDENCIES serialization)
  elseif(NOT Boost_VERSION VERSION_LESS 105500 AND Boost_VERSION VERSION_LESS 105600)
    set(_Boost_CHRONO_DEPENDENCIES system)
    set(_Boost_COROUTINE_DEPENDENCIES context system)
    set(_Boost_FILESYSTEM_DEPENDENCIES system)
    set(_Boost_IOSTREAMS_DEPENDENCIES regex)
    set(_Boost_LOG_DEPENDENCIES log_setup date_time system filesystem thread regex chrono)
    set(_Boost_MATH_DEPENDENCIES math_c99 math_c99f math_c99l math_tr1 math_tr1f math_tr1l regex random)
    set(_Boost_MPI_DEPENDENCIES serialization)
    set(_Boost_MPI_PYTHON_DEPENDENCIES python${component_python_version} mpi serialization)
    set(_Boost_THREAD_DEPENDENCIES chrono system date_time atomic)
    set(_Boost_TIMER_DEPENDENCIES chrono system)
    set(_Boost_WAVE_DEPENDENCIES filesystem system serialization thread chrono date_time atomic)
    set(_Boost_WSERIALIZATION_DEPENDENCIES serialization)
  elseif(NOT Boost_VERSION VERSION_LESS 105600 AND Boost_VERSION VERSION_LESS 105900)
    set(_Boost_CHRONO_DEPENDENCIES system)
    set(_Boost_COROUTINE_DEPENDENCIES context system)
    set(_Boost_FILESYSTEM_DEPENDENCIES system)
    set(_Boost_IOSTREAMS_DEPENDENCIES regex)
    set(_Boost_LOG_DEPENDENCIES log_setup date_time system filesystem thread regex chrono)
    set(_Boost_MATH_DEPENDENCIES math_c99 math_c99f math_c99l math_tr1 math_tr1f math_tr1l atomic)
    set(_Boost_MPI_DEPENDENCIES serialization)
    set(_Boost_MPI_PYTHON_DEPENDENCIES python${component_python_version} mpi serialization)
    set(_Boost_RANDOM_DEPENDENCIES system)
    set(_Boost_THREAD_DEPENDENCIES chrono system date_time atomic)
    set(_Boost_TIMER_DEPENDENCIES chrono system)
    set(_Boost_WAVE_DEPENDENCIES filesystem system serialization thread chrono date_time atomic)
    set(_Boost_WSERIALIZATION_DEPENDENCIES serialization)
  elseif(NOT Boost_VERSION VERSION_LESS 105900 AND Boost_VERSION VERSION_LESS 106000)
    set(_Boost_CHRONO_DEPENDENCIES system)
    set(_Boost_COROUTINE_DEPENDENCIES context system)
    set(_Boost_FILESYSTEM_DEPENDENCIES system)
    set(_Boost_IOSTREAMS_DEPENDENCIES regex)
    set(_Boost_LOG_DEPENDENCIES log_setup date_time system filesystem thread regex chrono atomic)
    set(_Boost_MATH_DEPENDENCIES math_c99 math_c99f math_c99l math_tr1 math_tr1f math_tr1l atomic)
    set(_Boost_MPI_DEPENDENCIES serialization)
    set(_Boost_MPI_PYTHON_DEPENDENCIES python${component_python_version} mpi serialization)
    set(_Boost_RANDOM_DEPENDENCIES system)
    set(_Boost_THREAD_DEPENDENCIES chrono system date_time atomic)
    set(_Boost_TIMER_DEPENDENCIES chrono system)
    set(_Boost_WAVE_DEPENDENCIES filesystem system serialization thread chrono date_time atomic)
    set(_Boost_WSERIALIZATION_DEPENDENCIES serialization)
  elseif(NOT Boost_VERSION VERSION_LESS 106000 AND Boost_VERSION VERSION_LESS 106100)
    set(_Boost_CHRONO_DEPENDENCIES system)
    set(_Boost_COROUTINE_DEPENDENCIES context system)
    set(_Boost_FILESYSTEM_DEPENDENCIES system)
    set(_Boost_IOSTREAMS_DEPENDENCIES regex)
    set(_Boost_LOG_DEPENDENCIES date_time log_setup system filesystem thread regex chrono atomic)
    set(_Boost_MATH_DEPENDENCIES math_c99 math_c99f math_c99l math_tr1 math_tr1f math_tr1l atomic)
    set(_Boost_MPI_DEPENDENCIES serialization)
    set(_Boost_MPI_PYTHON_DEPENDENCIES python${component_python_version} mpi serialization)
    set(_Boost_RANDOM_DEPENDENCIES system)
    set(_Boost_THREAD_DEPENDENCIES chrono system date_time atomic)
    set(_Boost_TIMER_DEPENDENCIES chrono system)
    set(_Boost_WAVE_DEPENDENCIES filesystem system serialization thread chrono date_time atomic)
    set(_Boost_WSERIALIZATION_DEPENDENCIES serialization)
  elseif(NOT Boost_VERSION VERSION_LESS 106100 AND Boost_VERSION VERSION_LESS 106200)
    set(_Boost_CHRONO_DEPENDENCIES system)
    set(_Boost_CONTEXT_DEPENDENCIES thread chrono system date_time)
    set(_Boost_COROUTINE_DEPENDENCIES context system)
    set(_Boost_FILESYSTEM_DEPENDENCIES system)
    set(_Boost_IOSTREAMS_DEPENDENCIES regex)
    set(_Boost_LOG_DEPENDENCIES date_time log_setup system filesystem thread regex chrono atomic)
    set(_Boost_MATH_DEPENDENCIES math_c99 math_c99f math_c99l math_tr1 math_tr1f math_tr1l atomic)
    set(_Boost_MPI_DEPENDENCIES serialization)
    set(_Boost_MPI_PYTHON_DEPENDENCIES python${component_python_version} mpi serialization)
    set(_Boost_RANDOM_DEPENDENCIES system)
    set(_Boost_THREAD_DEPENDENCIES chrono system date_time atomic)
    set(_Boost_WAVE_DEPENDENCIES filesystem system serialization thread chrono date_time atomic)
    set(_Boost_WSERIALIZATION_DEPENDENCIES serialization)
  elseif(NOT Boost_VERSION VERSION_LESS 106200 AND Boost_VERSION VERSION_LESS 106300)
    set(_Boost_CHRONO_DEPENDENCIES system)
    set(_Boost_CONTEXT_DEPENDENCIES thread chrono system date_time)
    set(_Boost_COROUTINE_DEPENDENCIES context system)
    set(_Boost_FIBER_DEPENDENCIES context thread chrono system date_time)
    set(_Boost_FILESYSTEM_DEPENDENCIES system)
    set(_Boost_IOSTREAMS_DEPENDENCIES regex)
    set(_Boost_LOG_DEPENDENCIES date_time log_setup system filesystem thread regex chrono atomic)
    set(_Boost_MATH_DEPENDENCIES math_c99 math_c99f math_c99l math_tr1 math_tr1f math_tr1l atomic)
    set(_Boost_MPI_DEPENDENCIES serialization)
    set(_Boost_MPI_PYTHON_DEPENDENCIES python${component_python_version} mpi serialization)
    set(_Boost_RANDOM_DEPENDENCIES system)
    set(_Boost_THREAD_DEPENDENCIES chrono system date_time atomic)
    set(_Boost_WAVE_DEPENDENCIES filesystem system serialization thread chrono date_time atomic)
    set(_Boost_WSERIALIZATION_DEPENDENCIES serialization)
  elseif(NOT Boost_VERSION VERSION_LESS 106300 AND Boost_VERSION VERSION_LESS 106500)
    set(_Boost_CHRONO_DEPENDENCIES system)
    set(_Boost_CONTEXT_DEPENDENCIES thread chrono system date_time)
    set(_Boost_COROUTINE_DEPENDENCIES context system)
    set(_Boost_COROUTINE2_DEPENDENCIES context fiber thread chrono system date_time)
    set(_Boost_FIBER_DEPENDENCIES context thread chrono system date_time)
    set(_Boost_FILESYSTEM_DEPENDENCIES system)
    set(_Boost_IOSTREAMS_DEPENDENCIES regex)
    set(_Boost_LOG_DEPENDENCIES date_time log_setup system filesystem thread regex chrono atomic)
    set(_Boost_MATH_DEPENDENCIES math_c99 math_c99f math_c99l math_tr1 math_tr1f math_tr1l atomic)
    set(_Boost_MPI_DEPENDENCIES serialization)
    set(_Boost_MPI_PYTHON_DEPENDENCIES python${component_python_version} mpi serialization)
    set(_Boost_RANDOM_DEPENDENCIES system)
    set(_Boost_THREAD_DEPENDENCIES chrono system date_time atomic)
    set(_Boost_WAVE_DEPENDENCIES filesystem system serialization thread chrono date_time atomic)
    set(_Boost_WSERIALIZATION_DEPENDENCIES serialization)
  elseif(NOT Boost_VERSION VERSION_LESS 106500 AND Boost_VERSION VERSION_LESS 106700)
    set(_Boost_CHRONO_DEPENDENCIES system)
    set(_Boost_CONTEXT_DEPENDENCIES thread chrono system date_time)
    set(_Boost_COROUTINE_DEPENDENCIES context system)
    set(_Boost_FIBER_DEPENDENCIES context thread chrono system date_time)
    set(_Boost_FILESYSTEM_DEPENDENCIES system)
    set(_Boost_IOSTREAMS_DEPENDENCIES regex)
    set(_Boost_LOG_DEPENDENCIES date_time log_setup system filesystem thread regex chrono atomic)
    set(_Boost_MATH_DEPENDENCIES math_c99 math_c99f math_c99l math_tr1 math_tr1f math_tr1l atomic)
    set(_Boost_MPI_DEPENDENCIES serialization)
    set(_Boost_MPI_PYTHON_DEPENDENCIES python${component_python_version} mpi serialization)
    set(_Boost_NUMPY_DEPENDENCIES python${component_python_version})
    set(_Boost_RANDOM_DEPENDENCIES system)
    set(_Boost_THREAD_DEPENDENCIES chrono system date_time atomic)
    set(_Boost_TIMER_DEPENDENCIES chrono system)
    set(_Boost_WAVE_DEPENDENCIES filesystem system serialization thread chrono date_time atomic)
    set(_Boost_WSERIALIZATION_DEPENDENCIES serialization)
  elseif(NOT Boost_VERSION VERSION_LESS 106700 AND Boost_VERSION VERSION_LESS 106800)
    set(_Boost_CHRONO_DEPENDENCIES system)
    set(_Boost_CONTEXT_DEPENDENCIES thread chrono system date_time)
    set(_Boost_COROUTINE_DEPENDENCIES context system)
    set(_Boost_FIBER_DEPENDENCIES context thread chrono system date_time)
    set(_Boost_FILESYSTEM_DEPENDENCIES system)
    set(_Boost_IOSTREAMS_DEPENDENCIES regex)
    set(_Boost_LOG_DEPENDENCIES date_time log_setup system filesystem thread regex chrono atomic)
    set(_Boost_MATH_DEPENDENCIES math_c99 math_c99f math_c99l math_tr1 math_tr1f math_tr1l atomic)
    set(_Boost_MPI_DEPENDENCIES serialization)
    set(_Boost_MPI_PYTHON_DEPENDENCIES python${component_python_version} mpi serialization)
    set(_Boost_NUMPY_DEPENDENCIES python${component_python_version})
    set(_Boost_RANDOM_DEPENDENCIES system)
    set(_Boost_THREAD_DEPENDENCIES chrono system date_time atomic)
    set(_Boost_TIMER_DEPENDENCIES chrono system)
    set(_Boost_WAVE_DEPENDENCIES filesystem system serialization thread chrono date_time atomic)
    set(_Boost_WSERIALIZATION_DEPENDENCIES serialization)
  elseif(NOT Boost_VERSION VERSION_LESS 106800 AND Boost_VERSION VERSION_LESS 106900)
    set(_Boost_CHRONO_DEPENDENCIES system)
    set(_Boost_CONTEXT_DEPENDENCIES thread chrono system date_time)
    set(_Boost_CONTRACT_DEPENDENCIES thread chrono system date_time)
    set(_Boost_COROUTINE_DEPENDENCIES context system)
    set(_Boost_FIBER_DEPENDENCIES context thread chrono system date_time)
    set(_Boost_FILESYSTEM_DEPENDENCIES system)
    set(_Boost_IOSTREAMS_DEPENDENCIES regex)
    set(_Boost_LOG_DEPENDENCIES date_time log_setup system filesystem thread regex chrono atomic)
    set(_Boost_MATH_DEPENDENCIES math_c99 math_c99f math_c99l math_tr1 math_tr1f math_tr1l atomic)
    set(_Boost_MPI_DEPENDENCIES serialization)
    set(_Boost_MPI_PYTHON_DEPENDENCIES python${component_python_version} mpi serialization)
    set(_Boost_NUMPY_DEPENDENCIES python${component_python_version})
    set(_Boost_RANDOM_DEPENDENCIES system)
    set(_Boost_THREAD_DEPENDENCIES chrono system date_time atomic)
    set(_Boost_TIMER_DEPENDENCIES chrono system)
    set(_Boost_WAVE_DEPENDENCIES filesystem system serialization thread chrono date_time atomic)
    set(_Boost_WSERIALIZATION_DEPENDENCIES serialization)
  elseif(NOT Boost_VERSION VERSION_LESS 106900 AND Boost_VERSION VERSION_LESS 107000)
    set(_Boost_CONTRACT_DEPENDENCIES thread chrono date_time)
    set(_Boost_COROUTINE_DEPENDENCIES context)
    set(_Boost_FIBER_DEPENDENCIES context)
    set(_Boost_IOSTREAMS_DEPENDENCIES regex)
    set(_Boost_LOG_DEPENDENCIES date_time log_setup filesystem thread regex chrono atomic)
    set(_Boost_MATH_DEPENDENCIES math_c99 math_c99f math_c99l math_tr1 math_tr1f math_tr1l atomic)
    set(_Boost_MPI_DEPENDENCIES serialization)
    set(_Boost_MPI_PYTHON_DEPENDENCIES python${component_python_version} mpi serialization)
    set(_Boost_NUMPY_DEPENDENCIES python${component_python_version})
    set(_Boost_THREAD_DEPENDENCIES chrono date_time atomic)
    set(_Boost_TIMER_DEPENDENCIES chrono system)
    set(_Boost_WAVE_DEPENDENCIES filesystem serialization thread chrono date_time atomic)
    set(_Boost_WSERIALIZATION_DEPENDENCIES serialization)
  else()
    if(NOT Boost_VERSION VERSION_LESS 107000)
      set(_Boost_CONTRACT_DEPENDENCIES thread chrono date_time)
      set(_Boost_COROUTINE_DEPENDENCIES context)
      set(_Boost_FIBER_DEPENDENCIES context)
      set(_Boost_IOSTREAMS_DEPENDENCIES regex)
      set(_Boost_LOG_DEPENDENCIES date_time log_setup filesystem thread regex chrono atomic)
      set(_Boost_MATH_DEPENDENCIES math_c99 math_c99f math_c99l math_tr1 math_tr1f math_tr1l atomic)
      set(_Boost_MPI_DEPENDENCIES serialization)
      set(_Boost_MPI_PYTHON_DEPENDENCIES python${component_python_version} mpi serialization)
      set(_Boost_NUMPY_DEPENDENCIES python${component_python_version})
      set(_Boost_THREAD_DEPENDENCIES chrono date_time atomic)
      set(_Boost_TIMER_DEPENDENCIES chrono system)
      set(_Boost_WAVE_DEPENDENCIES filesystem serialization thread chrono date_time atomic)
      set(_Boost_WSERIALIZATION_DEPENDENCIES serialization)
    endif()
    if(NOT Boost_VERSION VERSION_LESS 107100)
      message(WARNING "New Boost version may have incorrect or missing dependencies and imported targets")
    endif()
  endif()

  string(TOUPPER ${component} uppercomponent)
  set(${_ret} ${_Boost_${uppercomponent}_DEPENDENCIES} PARENT_SCOPE)
  set(_Boost_IMPORTED_TARGETS ${_Boost_IMPORTED_TARGETS} PARENT_SCOPE)

  string(REGEX REPLACE ";" " " _boost_DEPS_STRING "${_Boost_${uppercomponent}_DEPENDENCIES}")
  if (NOT _boost_DEPS_STRING)
    set(_boost_DEPS_STRING "(none)")
  endif()
  # message(STATUS "Dependencies for Boost::${component}: ${_boost_DEPS_STRING}")
endfunction()

#
# Get component headers.  This is the primary header (or headers) for
# a given component, and is used to check that the headers are present
# as well as the library itself as an extra sanity check of the build
# environment.
#
# component - the component to check
# _hdrs
#
function(_Boost_COMPONENT_HEADERS component _hdrs)
  # Handle Python version suffixes
  if(component MATCHES "^(python|mpi_python|numpy)([0-9][0-9]?|[0-9]\\.[0-9])\$")
    set(component "${CMAKE_MATCH_1}")
    set(component_python_version "${CMAKE_MATCH_2}")
  endif()

  # Note: new boost components will require adding here.  The header
  # must be present in all versions of Boost providing a library.
  set(_Boost_ATOMIC_HEADERS              "boost/atomic.hpp")
  set(_Boost_CHRONO_HEADERS              "boost/chrono.hpp")
  set(_Boost_CONTAINER_HEADERS           "boost/container/container_fwd.hpp")
  set(_Boost_CONTRACT_HEADERS            "boost/contract.hpp")
  if(Boost_VERSION VERSION_LESS 106100)
    set(_Boost_CONTEXT_HEADERS           "boost/context/all.hpp")
  else()
    set(_Boost_CONTEXT_HEADERS           "boost/context/detail/fcontext.hpp")
  endif()
  set(_Boost_COROUTINE_HEADERS           "boost/coroutine/all.hpp")
  set(_Boost_DATE_TIME_HEADERS           "boost/date_time/date.hpp")
  set(_Boost_EXCEPTION_HEADERS           "boost/exception/exception.hpp")
  set(_Boost_FIBER_HEADERS               "boost/fiber/all.hpp")
  set(_Boost_FILESYSTEM_HEADERS          "boost/filesystem/path.hpp")
  set(_Boost_GRAPH_HEADERS               "boost/graph/adjacency_list.hpp")
  set(_Boost_GRAPH_PARALLEL_HEADERS      "boost/graph/adjacency_list.hpp")
  set(_Boost_IOSTREAMS_HEADERS           "boost/iostreams/stream.hpp")
  set(_Boost_LOCALE_HEADERS              "boost/locale.hpp")
  set(_Boost_LOG_HEADERS                 "boost/log/core.hpp")
  set(_Boost_LOG_SETUP_HEADERS           "boost/log/detail/setup_config.hpp")
  set(_Boost_MATH_HEADERS                "boost/math_fwd.hpp")
  set(_Boost_MATH_C99_HEADERS            "boost/math/tr1.hpp")
  set(_Boost_MATH_C99F_HEADERS           "boost/math/tr1.hpp")
  set(_Boost_MATH_C99L_HEADERS           "boost/math/tr1.hpp")
  set(_Boost_MATH_TR1_HEADERS            "boost/math/tr1.hpp")
  set(_Boost_MATH_TR1F_HEADERS           "boost/math/tr1.hpp")
  set(_Boost_MATH_TR1L_HEADERS           "boost/math/tr1.hpp")
  set(_Boost_MPI_HEADERS                 "boost/mpi.hpp")
  set(_Boost_MPI_PYTHON_HEADERS          "boost/mpi/python/config.hpp")
  set(_Boost_NUMPY_HEADERS               "boost/python/numpy.hpp")
  set(_Boost_PRG_EXEC_MONITOR_HEADERS    "boost/test/prg_exec_monitor.hpp")
  set(_Boost_PROGRAM_OPTIONS_HEADERS     "boost/program_options.hpp")
  set(_Boost_PYTHON_HEADERS              "boost/python.hpp")
  set(_Boost_RANDOM_HEADERS              "boost/random.hpp")
  set(_Boost_REGEX_HEADERS               "boost/regex.hpp")
  set(_Boost_SERIALIZATION_HEADERS       "boost/serialization/serialization.hpp")
  set(_Boost_SIGNALS_HEADERS             "boost/signals.hpp")
  set(_Boost_STACKTRACE_ADDR2LINE_HEADERS "boost/stacktrace.hpp")
  set(_Boost_STACKTRACE_BACKTRACE_HEADERS "boost/stacktrace.hpp")
  set(_Boost_STACKTRACE_BASIC_HEADERS    "boost/stacktrace.hpp")
  set(_Boost_STACKTRACE_NOOP_HEADERS     "boost/stacktrace.hpp")
  set(_Boost_STACKTRACE_WINDBG_CACHED_HEADERS "boost/stacktrace.hpp")
  set(_Boost_STACKTRACE_WINDBG_HEADERS   "boost/stacktrace.hpp")
  set(_Boost_SYSTEM_HEADERS              "boost/system/config.hpp")
  set(_Boost_TEST_EXEC_MONITOR_HEADERS   "boost/test/test_exec_monitor.hpp")
  set(_Boost_THREAD_HEADERS              "boost/thread.hpp")
  set(_Boost_TIMER_HEADERS               "boost/timer.hpp")
  set(_Boost_TYPE_ERASURE_HEADERS        "boost/type_erasure/config.hpp")
  set(_Boost_UNIT_TEST_FRAMEWORK_HEADERS "boost/test/framework.hpp")
  set(_Boost_WAVE_HEADERS                "boost/wave.hpp")
  set(_Boost_WSERIALIZATION_HEADERS      "boost/archive/text_wiarchive.hpp")
  if(WIN32)
    set(_Boost_BZIP2_HEADERS             "boost/iostreams/filter/bzip2.hpp")
    set(_Boost_ZLIB_HEADERS              "boost/iostreams/filter/zlib.hpp")
  endif()

  string(TOUPPER ${component} uppercomponent)
  set(${_hdrs} ${_Boost_${uppercomponent}_HEADERS} PARENT_SCOPE)

  string(REGEX REPLACE ";" " " _boost_HDRS_STRING "${_Boost_${uppercomponent}_HEADERS}")
  if (NOT _boost_HDRS_STRING)
    set(_boost_HDRS_STRING "(none)")
  endif()
  # message(STATUS "Headers for Boost::${component}: ${_boost_HDRS_STRING}")
endfunction()

#
# Determine if any missing dependencies require adding to the component list.
#
# Sets _Boost_${COMPONENT}_DEPENDENCIES for each required component,
# plus _Boost_IMPORTED_TARGETS (TRUE if imported targets should be
# defined; FALSE if dependency information is unavailable).
#
# componentvar - the component list variable name
# extravar - the indirect dependency list variable name
#
#
function(_Boost_MISSING_DEPENDENCIES componentvar extravar)
  # _boost_unprocessed_components - list of components requiring processing
  # _boost_processed_components - components already processed (or currently being processed)
  # _boost_new_components - new components discovered for future processing
  #
  list(APPEND _boost_unprocessed_components ${${componentvar}})

  while(_boost_unprocessed_components)
    list(APPEND _boost_processed_components ${_boost_unprocessed_components})
    foreach(component ${_boost_unprocessed_components})
      string(TOUPPER ${component} uppercomponent)
      set(${_ret} ${_Boost_${uppercomponent}_DEPENDENCIES} PARENT_SCOPE)
      _Boost_COMPONENT_DEPENDENCIES("${component}" _Boost_${uppercomponent}_DEPENDENCIES)
      set(_Boost_${uppercomponent}_DEPENDENCIES ${_Boost_${uppercomponent}_DEPENDENCIES} PARENT_SCOPE)
      set(_Boost_IMPORTED_TARGETS ${_Boost_IMPORTED_TARGETS} PARENT_SCOPE)
      foreach(componentdep ${_Boost_${uppercomponent}_DEPENDENCIES})
        if (NOT ("${componentdep}" IN_LIST _boost_processed_components OR "${componentdep}" IN_LIST _boost_new_components))
          list(APPEND _boost_new_components ${componentdep})
        endif()
      endforeach()
    endforeach()
    set(_boost_unprocessed_components ${_boost_new_components})
    unset(_boost_new_components)
  endwhile()
  set(_boost_extra_components ${_boost_processed_components})
  if(_boost_extra_components AND ${componentvar})
    list(REMOVE_ITEM _boost_extra_components ${${componentvar}})
  endif()
  set(${componentvar} ${_boost_processed_components} PARENT_SCOPE)
  set(${extravar} ${_boost_extra_components} PARENT_SCOPE)
endfunction()

#
# Some boost libraries may require particular set of compler features.
# The very first one was `boost::fiber` introduced in Boost 1.62.
# One can check required compiler features of it in
# `${Boost_ROOT}/libs/fiber/build/Jamfile.v2`.
#
function(_Boost_COMPILER_FEATURES component _ret)
  # Boost >= 1.62 and < 1.67
  if(NOT Boost_VERSION VERSION_LESS 106200 AND Boost_VERSION VERSION_LESS 106700)
    set(_Boost_FIBER_COMPILER_FEATURES
        cxx_alias_templates
        cxx_auto_type
        cxx_constexpr
        cxx_defaulted_functions
        cxx_final
        cxx_lambdas
        cxx_noexcept
        cxx_nullptr
        cxx_rvalue_references
        cxx_thread_local
        cxx_variadic_templates
    )
  endif()
  string(TOUPPER ${component} uppercomponent)
  set(${_ret} ${_Boost_${uppercomponent}_COMPILER_FEATURES} PARENT_SCOPE)
endfunction()

#
# Update library search directory hint variable with paths used by prebuilt boost binaries.
#
# Prebuilt windows binaries (https://sourceforge.net/projects/boost/files/boost-binaries/)
# have library directories named using MSVC compiler version and architecture.
# This function would append corresponding directories if MSVC is a current compiler,
# so having `BOOST_ROOT` would be enough to specify to find everything.
#
function(_Boost_UPDATE_WINDOWS_LIBRARY_SEARCH_DIRS_WITH_PREBUILT_PATHS componentlibvar basedir)
  if("x${CMAKE_CXX_COMPILER_ID}" STREQUAL "xMSVC")
    if(CMAKE_SIZEOF_VOID_P EQUAL 8)
      set(_arch_suffix 64)
    else()
      set(_arch_suffix 32)
    endif()
    if(MSVC_TOOLSET_VERSION GREATER_EQUAL 141)
      list(APPEND ${componentlibvar} ${basedir}/lib${_arch_suffix}-msvc-14.1)
      list(APPEND ${componentlibvar} ${basedir}/lib${_arch_suffix}-msvc-14.0)
    elseif(MSVC_TOOLSET_VERSION GREATER_EQUAL 80)
      math(EXPR _toolset_major_version "${MSVC_TOOLSET_VERSION} / 10")
      list(APPEND ${componentlibvar} ${basedir}/lib${_arch_suffix}-msvc-${_toolset_major_version}.0)
    endif()
    set(${componentlibvar} ${${componentlibvar}} PARENT_SCOPE)
  endif()
endfunction()

#
# End functions/macros
#
#-------------------------------------------------------------------------------

#-------------------------------------------------------------------------------
# main.
#-------------------------------------------------------------------------------


# If the user sets Boost_LIBRARY_DIR, use it as the default for both
# configurations.
if(NOT Boost_LIBRARY_DIR_RELEASE AND Boost_LIBRARY_DIR)
  set(Boost_LIBRARY_DIR_RELEASE "${Boost_LIBRARY_DIR}")
endif()
if(NOT Boost_LIBRARY_DIR_DEBUG AND Boost_LIBRARY_DIR)
  set(Boost_LIBRARY_DIR_DEBUG   "${Boost_LIBRARY_DIR}")
endif()

if(NOT DEFINED Boost_USE_DEBUG_LIBS)
  set(Boost_USE_DEBUG_LIBS TRUE)
endif()
if(NOT DEFINED Boost_USE_RELEASE_LIBS)
  set(Boost_USE_RELEASE_LIBS TRUE)
endif()
if(NOT DEFINED Boost_USE_MULTITHREADED)
  set(Boost_USE_MULTITHREADED TRUE)
endif()
if(NOT DEFINED Boost_USE_DEBUG_RUNTIME)
  set(Boost_USE_DEBUG_RUNTIME TRUE)
endif()

# Check the version of Boost against the requested version.
if(Boost_FIND_VERSION AND NOT Boost_FIND_VERSION_MINOR)
  message(SEND_ERROR "When requesting a specific version of Boost, you must provide at least the major and minor version numbers, e.g., 1.34")
endif()

if(Boost_FIND_VERSION_EXACT)
  # The version may appear in a directory with or without the patch
  # level, even when the patch level is non-zero.
  set(_boost_TEST_VERSIONS
    "${Boost_FIND_VERSION_MAJOR}.${Boost_FIND_VERSION_MINOR}.${Boost_FIND_VERSION_PATCH}"
    "${Boost_FIND_VERSION_MAJOR}.${Boost_FIND_VERSION_MINOR}")
else()
  # The user has not requested an exact version.  Among known
  # versions, find those that are acceptable to the user request.
  #
  # Note: When adding a new Boost release, also update the dependency
  # information in _Boost_COMPONENT_DEPENDENCIES and
  # _Boost_COMPONENT_HEADERS.  See the instructions at the top of
  # _Boost_COMPONENT_DEPENDENCIES.
  set(_Boost_KNOWN_VERSIONS ${Boost_ADDITIONAL_VERSIONS}
    "1.70.0" "1.70" "1.69.0" "1.69"
    "1.68.0" "1.68" "1.67.0" "1.67" "1.66.0" "1.66" "1.65.1" "1.65.0" "1.65"
    "1.64.0" "1.64" "1.63.0" "1.63" "1.62.0" "1.62" "1.61.0" "1.61" "1.60.0" "1.60"
    "1.59.0" "1.59" "1.58.0" "1.58" "1.57.0" "1.57" "1.56.0" "1.56" "1.55.0" "1.55"
    "1.54.0" "1.54" "1.53.0" "1.53" "1.52.0" "1.52" "1.51.0" "1.51"
    "1.50.0" "1.50" "1.49.0" "1.49" "1.48.0" "1.48" "1.47.0" "1.47" "1.46.1"
    "1.46.0" "1.46" "1.45.0" "1.45" "1.44.0" "1.44" "1.43.0" "1.43" "1.42.0" "1.42"
    "1.41.0" "1.41" "1.40.0" "1.40" "1.39.0" "1.39" "1.38.0" "1.38" "1.37.0" "1.37"
    "1.36.1" "1.36.0" "1.36" "1.35.1" "1.35.0" "1.35" "1.34.1" "1.34.0"
    "1.34" "1.33.1" "1.33.0" "1.33")

  set(_boost_TEST_VERSIONS)
  if(Boost_FIND_VERSION)
    set(_Boost_FIND_VERSION_SHORT "${Boost_FIND_VERSION_MAJOR}.${Boost_FIND_VERSION_MINOR}")
    # Select acceptable versions.
    foreach(version ${_Boost_KNOWN_VERSIONS})
      if(NOT "${version}" VERSION_LESS "${Boost_FIND_VERSION}")
        # This version is high enough.
        list(APPEND _boost_TEST_VERSIONS "${version}")
      elseif("${version}.99" VERSION_EQUAL "${_Boost_FIND_VERSION_SHORT}.99")
        # This version is a short-form for the requested version with
        # the patch level dropped.
        list(APPEND _boost_TEST_VERSIONS "${version}")
      endif()
    endforeach()
  else()
    # Any version is acceptable.
    set(_boost_TEST_VERSIONS "${_Boost_KNOWN_VERSIONS}")
  endif()
endif()

# The reason that we failed to find Boost. This will be set to a
# user-friendly message when we fail to find some necessary piece of
# Boost.
set(Boost_ERROR_REASON)

if(Boost_DEBUG)
  # Output some of their choices
  message(STATUS "[ ${CMAKE_CURRENT_LIST_FILE}:${CMAKE_CURRENT_LIST_LINE} ] "
                 "_boost_TEST_VERSIONS = ${_boost_TEST_VERSIONS}")
  message(STATUS "[ ${CMAKE_CURRENT_LIST_FILE}:${CMAKE_CURRENT_LIST_LINE} ] "
                 "Boost_USE_MULTITHREADED = ${Boost_USE_MULTITHREADED}")
  message(STATUS "[ ${CMAKE_CURRENT_LIST_FILE}:${CMAKE_CURRENT_LIST_LINE} ] "
                 "Boost_USE_STATIC_LIBS = ${Boost_USE_STATIC_LIBS}")
  message(STATUS "[ ${CMAKE_CURRENT_LIST_FILE}:${CMAKE_CURRENT_LIST_LINE} ] "
                 "Boost_USE_STATIC_RUNTIME = ${Boost_USE_STATIC_RUNTIME}")
  message(STATUS "[ ${CMAKE_CURRENT_LIST_FILE}:${CMAKE_CURRENT_LIST_LINE} ] "
                 "Boost_ADDITIONAL_VERSIONS = ${Boost_ADDITIONAL_VERSIONS}")
  message(STATUS "[ ${CMAKE_CURRENT_LIST_FILE}:${CMAKE_CURRENT_LIST_LINE} ] "
                 "Boost_NO_SYSTEM_PATHS = ${Boost_NO_SYSTEM_PATHS}")
endif()

# Supply Boost_LIB_DIAGNOSTIC_DEFINITIONS as a convenience target. It
# will only contain any interface definitions on WIN32, but is created
# on all platforms to keep end user code free from platform dependent
# code.  Also provide convenience targets to disable autolinking and
# enable dynamic linking.
if(NOT TARGET Boost::diagnostic_definitions)
  add_library(Boost::diagnostic_definitions INTERFACE IMPORTED)
  add_library(Boost::disable_autolinking INTERFACE IMPORTED)
  add_library(Boost::dynamic_linking INTERFACE IMPORTED)
endif()
if(WIN32)
  # In windows, automatic linking is performed, so you do not have
  # to specify the libraries.  If you are linking to a dynamic
  # runtime, then you can choose to link to either a static or a
  # dynamic Boost library, the default is to do a static link.  You
  # can alter this for a specific library "whatever" by defining
  # BOOST_WHATEVER_DYN_LINK to force Boost library "whatever" to be
  # linked dynamically.  Alternatively you can force all Boost
  # libraries to dynamic link by defining BOOST_ALL_DYN_LINK.

  # This feature can be disabled for Boost library "whatever" by
  # defining BOOST_WHATEVER_NO_LIB, or for all of Boost by defining
  # BOOST_ALL_NO_LIB.

  # If you want to observe which libraries are being linked against
  # then defining BOOST_LIB_DIAGNOSTIC will cause the auto-linking
  # code to emit a #pragma message each time a library is selected
  # for linking.
  set(Boost_LIB_DIAGNOSTIC_DEFINITIONS "-DBOOST_LIB_DIAGNOSTIC")
  set_target_properties(Boost::diagnostic_definitions PROPERTIES
    INTERFACE_COMPILE_DEFINITIONS "BOOST_LIB_DIAGNOSTIC")
  set_target_properties(Boost::disable_autolinking PROPERTIES
    INTERFACE_COMPILE_DEFINITIONS "BOOST_ALL_NO_LIB")
  set_target_properties(Boost::dynamic_linking PROPERTIES
    INTERFACE_COMPILE_DEFINITIONS "BOOST_ALL_DYN_LINK")
endif()

_Boost_CHECK_SPELLING(Boost_ROOT)
_Boost_CHECK_SPELLING(Boost_LIBRARYDIR)
_Boost_CHECK_SPELLING(Boost_INCLUDEDIR)

# Collect environment variable inputs as hints.  Do not consider changes.
foreach(v BOOSTROOT BOOST_ROOT BOOST_INCLUDEDIR BOOST_LIBRARYDIR)
  set(_env $ENV{${v}})
  if(_env)
    file(TO_CMAKE_PATH "${_env}" _ENV_${v})
  else()
    set(_ENV_${v} "")
  endif()
endforeach()
if(NOT _ENV_BOOST_ROOT AND _ENV_BOOSTROOT)
  set(_ENV_BOOST_ROOT "${_ENV_BOOSTROOT}")
endif()

# Collect inputs and cached results.  Detect changes since the last run.
if(NOT BOOST_ROOT AND BOOSTROOT)
  set(BOOST_ROOT "${BOOSTROOT}")
endif()
set(_Boost_VARS_DIR
  BOOST_ROOT
  Boost_NO_SYSTEM_PATHS
  )

if(Boost_DEBUG)
  message(STATUS "[ ${CMAKE_CURRENT_LIST_FILE}:${CMAKE_CURRENT_LIST_LINE} ] "
                 "Declared as CMake or Environmental Variables:")
  message(STATUS "[ ${CMAKE_CURRENT_LIST_FILE}:${CMAKE_CURRENT_LIST_LINE} ] "
                 "  BOOST_ROOT = ${BOOST_ROOT}")
  message(STATUS "[ ${CMAKE_CURRENT_LIST_FILE}:${CMAKE_CURRENT_LIST_LINE} ] "
                 "  BOOST_INCLUDEDIR = ${BOOST_INCLUDEDIR}")
  message(STATUS "[ ${CMAKE_CURRENT_LIST_FILE}:${CMAKE_CURRENT_LIST_LINE} ] "
                 "  BOOST_LIBRARYDIR = ${BOOST_LIBRARYDIR}")
  message(STATUS "[ ${CMAKE_CURRENT_LIST_FILE}:${CMAKE_CURRENT_LIST_LINE} ] "
                 "_boost_TEST_VERSIONS = ${_boost_TEST_VERSIONS}")
endif()

# ------------------------------------------------------------------------
#  Search for Boost include DIR
# ------------------------------------------------------------------------

set(_Boost_VARS_INC BOOST_INCLUDEDIR Boost_INCLUDE_DIR Boost_ADDITIONAL_VERSIONS)
_Boost_CHANGE_DETECT(_Boost_CHANGE_INCDIR ${_Boost_VARS_DIR} ${_Boost_VARS_INC})
# Clear Boost_INCLUDE_DIR if it did not change but other input affecting the
# location did.  We will find a new one based on the new inputs.
if(_Boost_CHANGE_INCDIR AND NOT _Boost_INCLUDE_DIR_CHANGED)
  unset(Boost_INCLUDE_DIR CACHE)
endif()

if(NOT Boost_INCLUDE_DIR)
  set(_boost_INCLUDE_SEARCH_DIRS "")
  if(BOOST_INCLUDEDIR)
    list(APPEND _boost_INCLUDE_SEARCH_DIRS ${BOOST_INCLUDEDIR})
  elseif(_ENV_BOOST_INCLUDEDIR)
    list(APPEND _boost_INCLUDE_SEARCH_DIRS ${_ENV_BOOST_INCLUDEDIR})
  endif()

  if( BOOST_ROOT )
    list(APPEND _boost_INCLUDE_SEARCH_DIRS ${BOOST_ROOT}/include ${BOOST_ROOT})
  elseif( _ENV_BOOST_ROOT )
    list(APPEND _boost_INCLUDE_SEARCH_DIRS ${_ENV_BOOST_ROOT}/include ${_ENV_BOOST_ROOT})
  endif()

  if( Boost_NO_SYSTEM_PATHS)
    list(APPEND _boost_INCLUDE_SEARCH_DIRS NO_CMAKE_SYSTEM_PATH NO_SYSTEM_ENVIRONMENT_PATH)
  else()
    if("x${CMAKE_CXX_COMPILER_ID}" STREQUAL "xMSVC")
      foreach(ver ${_boost_TEST_VERSIONS})
        string(REPLACE "." "_" ver "${ver}")
        list(APPEND _boost_INCLUDE_SEARCH_DIRS PATHS "C:/local/boost_${ver}")
      endforeach()
    endif()
    list(APPEND _boost_INCLUDE_SEARCH_DIRS PATHS
      C:/boost/include
      C:/boost
      /sw/local/include
      )
  endif()

  # Try to find Boost by stepping backwards through the Boost versions
  # we know about.
  # Build a list of path suffixes for each version.
  set(_boost_PATH_SUFFIXES)
  foreach(_boost_VER ${_boost_TEST_VERSIONS})
    # Add in a path suffix, based on the required version, ideally
    # we could read this from version.hpp, but for that to work we'd
    # need to know the include dir already
    set(_boost_BOOSTIFIED_VERSION)

    # Transform 1.35 => 1_35 and 1.36.0 => 1_36_0
    if(_boost_VER MATCHES "([0-9]+)\\.([0-9]+)\\.([0-9]+)")
        set(_boost_BOOSTIFIED_VERSION
          "${CMAKE_MATCH_1}_${CMAKE_MATCH_2}_${CMAKE_MATCH_3}")
    elseif(_boost_VER MATCHES "([0-9]+)\\.([0-9]+)")
        set(_boost_BOOSTIFIED_VERSION
          "${CMAKE_MATCH_1}_${CMAKE_MATCH_2}")
    endif()

    list(APPEND _boost_PATH_SUFFIXES
      "boost-${_boost_BOOSTIFIED_VERSION}"
      "boost_${_boost_BOOSTIFIED_VERSION}"
      "boost/boost-${_boost_BOOSTIFIED_VERSION}"
      "boost/boost_${_boost_BOOSTIFIED_VERSION}"
      )

  endforeach()

  if(Boost_DEBUG)
    message(STATUS "[ ${CMAKE_CURRENT_LIST_FILE}:${CMAKE_CURRENT_LIST_LINE} ] "
                   "Include debugging info:")
    message(STATUS "[ ${CMAKE_CURRENT_LIST_FILE}:${CMAKE_CURRENT_LIST_LINE} ] "
                   "  _boost_INCLUDE_SEARCH_DIRS = ${_boost_INCLUDE_SEARCH_DIRS}")
    message(STATUS "[ ${CMAKE_CURRENT_LIST_FILE}:${CMAKE_CURRENT_LIST_LINE} ] "
                   "  _boost_PATH_SUFFIXES = ${_boost_PATH_SUFFIXES}")
  endif()

  # Look for a standard boost header file.
  find_path(Boost_INCLUDE_DIR
    NAMES         boost/config.hpp
    HINTS         ${_boost_INCLUDE_SEARCH_DIRS}
    PATH_SUFFIXES ${_boost_PATH_SUFFIXES}
    )
endif()

# ------------------------------------------------------------------------
#  Extract version information from version.hpp
# ------------------------------------------------------------------------

# Set Boost_FOUND based only on header location and version.
# It will be updated below for component libraries.
if(Boost_INCLUDE_DIR)
  if(Boost_DEBUG)
    message(STATUS "[ ${CMAKE_CURRENT_LIST_FILE}:${CMAKE_CURRENT_LIST_LINE} ] "
                   "location of version.hpp: ${Boost_INCLUDE_DIR}/boost/version.hpp")
  endif()

  # Extract Boost_VERSION and Boost_LIB_VERSION from version.hpp
  set(Boost_VERSION 0)
  set(Boost_LIB_VERSION "")
  file(STRINGS "${Boost_INCLUDE_DIR}/boost/version.hpp" _boost_VERSION_HPP_CONTENTS REGEX "#define BOOST_(LIB_)?VERSION ")
  set(_Boost_VERSION_REGEX "([0-9]+)")
  set(_Boost_LIB_VERSION_REGEX "\"([0-9_]+)\"")
  foreach(v VERSION LIB_VERSION)
    if("${_boost_VERSION_HPP_CONTENTS}" MATCHES "#define BOOST_${v} ${_Boost_${v}_REGEX}")
      set(Boost_${v} "${CMAKE_MATCH_1}")
    endif()
  endforeach()
  unset(_boost_VERSION_HPP_CONTENTS)

  math(EXPR Boost_MAJOR_VERSION "${Boost_VERSION} / 100000")
  math(EXPR Boost_MINOR_VERSION "${Boost_VERSION} / 100 % 1000")
  math(EXPR Boost_SUBMINOR_VERSION "${Boost_VERSION} % 100")
  set(Boost_VERSION_STRING "${Boost_MAJOR_VERSION}.${Boost_MINOR_VERSION}.${Boost_SUBMINOR_VERSION}")

  string(APPEND Boost_ERROR_REASON
    "Boost version: ${Boost_MAJOR_VERSION}.${Boost_MINOR_VERSION}.${Boost_SUBMINOR_VERSION}\nBoost include path: ${Boost_INCLUDE_DIR}")
  if(Boost_DEBUG)
    message(STATUS "[ ${CMAKE_CURRENT_LIST_FILE}:${CMAKE_CURRENT_LIST_LINE} ] "
                   "version.hpp reveals boost "
                   "${Boost_MAJOR_VERSION}.${Boost_MINOR_VERSION}.${Boost_SUBMINOR_VERSION}")
  endif()

  if(Boost_FIND_VERSION)
    # Set Boost_FOUND based on requested version.
    set(_Boost_VERSION "${Boost_MAJOR_VERSION}.${Boost_MINOR_VERSION}.${Boost_SUBMINOR_VERSION}")
    if("${_Boost_VERSION}" VERSION_LESS "${Boost_FIND_VERSION}")
      set(Boost_FOUND 0)
      set(_Boost_VERSION_AGE "old")
    elseif(Boost_FIND_VERSION_EXACT AND
        NOT "${_Boost_VERSION}" VERSION_EQUAL "${Boost_FIND_VERSION}")
      set(Boost_FOUND 0)
      set(_Boost_VERSION_AGE "new")
    else()
      set(Boost_FOUND 1)
    endif()
    if(NOT Boost_FOUND)
      # State that we found a version of Boost that is too new or too old.
      string(APPEND Boost_ERROR_REASON
        "\nDetected version of Boost is too ${_Boost_VERSION_AGE}. Requested version was ${Boost_FIND_VERSION_MAJOR}.${Boost_FIND_VERSION_MINOR}")
      if (Boost_FIND_VERSION_PATCH)
        string(APPEND Boost_ERROR_REASON
          ".${Boost_FIND_VERSION_PATCH}")
      endif ()
      if (NOT Boost_FIND_VERSION_EXACT)
        string(APPEND Boost_ERROR_REASON " (or newer)")
      endif ()
      string(APPEND Boost_ERROR_REASON ".")
    endif ()
  else()
    # Caller will accept any Boost version.
    set(Boost_FOUND 1)
  endif()
else()
  set(Boost_FOUND 0)
  string(APPEND Boost_ERROR_REASON
    "Unable to find the Boost header files. Please set BOOST_ROOT to the root directory containing Boost or BOOST_INCLUDEDIR to the directory containing Boost's headers.")
endif()

# ------------------------------------------------------------------------
#  Prefix initialization
# ------------------------------------------------------------------------

set(Boost_LIB_PREFIX "")
if ( (GHSMULTI AND Boost_USE_STATIC_LIBS) OR
    (WIN32 AND Boost_USE_STATIC_LIBS AND NOT CYGWIN) )
  set(Boost_LIB_PREFIX "lib")
endif()

if ( NOT Boost_NAMESPACE )
  set(Boost_NAMESPACE "boost")
endif()

if(Boost_DEBUG)
  message(STATUS "[ ${CMAKE_CURRENT_LIST_FILE}:${CMAKE_CURRENT_LIST_LINE} ] "
    "Boost_LIB_PREFIX = ${Boost_LIB_PREFIX}")
  message(STATUS "[ ${CMAKE_CURRENT_LIST_FILE}:${CMAKE_CURRENT_LIST_LINE} ] "
    "Boost_NAMESPACE = ${Boost_NAMESPACE}")
endif()

# ------------------------------------------------------------------------
#  Suffix initialization and compiler suffix detection.
# ------------------------------------------------------------------------

set(_Boost_VARS_NAME
  Boost_NAMESPACE
  Boost_COMPILER
  Boost_THREADAPI
  Boost_USE_DEBUG_PYTHON
  Boost_USE_MULTITHREADED
  Boost_USE_STATIC_LIBS
  Boost_USE_STATIC_RUNTIME
  Boost_USE_STLPORT
  Boost_USE_STLPORT_DEPRECATED_NATIVE_IOSTREAMS
  )
_Boost_CHANGE_DETECT(_Boost_CHANGE_LIBNAME ${_Boost_VARS_NAME})

# Setting some more suffixes for the library
if (Boost_COMPILER)
  set(_boost_COMPILER ${Boost_COMPILER})
  if(Boost_DEBUG)
    message(STATUS "[ ${CMAKE_CURRENT_LIST_FILE}:${CMAKE_CURRENT_LIST_LINE} ] "
                   "using user-specified Boost_COMPILER = ${_boost_COMPILER}")
  endif()
else()
  # Attempt to guess the compiler suffix
  # NOTE: this is not perfect yet, if you experience any issues
  # please report them and use the Boost_COMPILER variable
  # to work around the problems.
  _Boost_GUESS_COMPILER_PREFIX(_boost_COMPILER)
  if(Boost_DEBUG)
    message(STATUS "[ ${CMAKE_CURRENT_LIST_FILE}:${CMAKE_CURRENT_LIST_LINE} ] "
      "guessed _boost_COMPILER = ${_boost_COMPILER}")
  endif()
endif()

set (_boost_MULTITHREADED "-mt")
if( NOT Boost_USE_MULTITHREADED )
  set (_boost_MULTITHREADED "")
endif()
if(Boost_DEBUG)
  message(STATUS "[ ${CMAKE_CURRENT_LIST_FILE}:${CMAKE_CURRENT_LIST_LINE} ] "
    "_boost_MULTITHREADED = ${_boost_MULTITHREADED}")
endif()

#======================
# Systematically build up the Boost ABI tag for the 'tagged' and 'versioned' layouts
# http://boost.org/doc/libs/1_66_0/more/getting_started/windows.html#library-naming
# http://boost.org/doc/libs/1_66_0/boost/config/auto_link.hpp
# http://boost.org/doc/libs/1_66_0/tools/build/src/tools/common.jam
# http://boost.org/doc/libs/1_66_0/boostcpp.jam
set( _boost_RELEASE_ABI_TAG "-")
set( _boost_DEBUG_ABI_TAG   "-")
# Key       Use this library when:
#  s        linking statically to the C++ standard library and
#           compiler runtime support libraries.
if(Boost_USE_STATIC_RUNTIME)
  set( _boost_RELEASE_ABI_TAG "${_boost_RELEASE_ABI_TAG}s")
  set( _boost_DEBUG_ABI_TAG   "${_boost_DEBUG_ABI_TAG}s")
endif()
#  g        using debug versions of the standard and runtime
#           support libraries
if(WIN32 AND Boost_USE_DEBUG_RUNTIME)
  if("x${CMAKE_CXX_COMPILER_ID}" STREQUAL "xMSVC"
          OR "x${CMAKE_CXX_COMPILER_ID}" STREQUAL "xClang"
          OR "x${CMAKE_CXX_COMPILER_ID}" STREQUAL "xIntel")
    string(APPEND _boost_DEBUG_ABI_TAG "g")
  endif()
endif()
#  y        using special debug build of python
if(Boost_USE_DEBUG_PYTHON)
  string(APPEND _boost_DEBUG_ABI_TAG "y")
endif()
#  d        using a debug version of your code
string(APPEND _boost_DEBUG_ABI_TAG "d")
#  p        using the STLport standard library rather than the
#           default one supplied with your compiler
if(Boost_USE_STLPORT)
  string(APPEND _boost_RELEASE_ABI_TAG "p")
  string(APPEND _boost_DEBUG_ABI_TAG "p")
endif()
#  n        using the STLport deprecated "native iostreams" feature
#           removed from the documentation in 1.43.0 but still present in
#           boost/config/auto_link.hpp
if(Boost_USE_STLPORT_DEPRECATED_NATIVE_IOSTREAMS)
  string(APPEND _boost_RELEASE_ABI_TAG "n")
  string(APPEND _boost_DEBUG_ABI_TAG "n")
endif()

#  -x86     Architecture and address model tag
#           First character is the architecture, then word-size, either 32 or 64
#           Only used in 'versioned' layout, added in Boost 1.66.0
if(DEFINED Boost_ARCHITECTURE)
  set(_boost_ARCHITECTURE_TAG "${Boost_ARCHITECTURE}")
  if(Boost_DEBUG)
    message(STATUS "[ ${CMAKE_CURRENT_LIST_FILE}:${CMAKE_CURRENT_LIST_LINE} ] "
      "using user-specified Boost_ARCHITECTURE = ${_boost_ARCHITECTURE_TAG}")
  endif()
else()
  set(_boost_ARCHITECTURE_TAG "")
  # {CMAKE_CXX_COMPILER_ARCHITECTURE_ID} is not currently set for all compilers
  if(NOT "x${CMAKE_CXX_COMPILER_ARCHITECTURE_ID}" STREQUAL "x" AND NOT Boost_VERSION VERSION_LESS 106600)
    string(APPEND _boost_ARCHITECTURE_TAG "-")
    # This needs to be kept in-sync with the section of CMakePlatformId.h.in
    # inside 'defined(_WIN32) && defined(_MSC_VER)'
    if(CMAKE_CXX_COMPILER_ARCHITECTURE_ID STREQUAL "IA64")
      string(APPEND _boost_ARCHITECTURE_TAG "i")
    elseif(CMAKE_CXX_COMPILER_ARCHITECTURE_ID STREQUAL "X86"
              OR CMAKE_CXX_COMPILER_ARCHITECTURE_ID STREQUAL "x64")
      string(APPEND _boost_ARCHITECTURE_TAG "x")
    elseif(CMAKE_CXX_COMPILER_ARCHITECTURE_ID MATCHES "^ARM")
      string(APPEND _boost_ARCHITECTURE_TAG "a")
    elseif(CMAKE_CXX_COMPILER_ARCHITECTURE_ID STREQUAL "MIPS")
      string(APPEND _boost_ARCHITECTURE_TAG "m")
    endif()

    if(CMAKE_SIZEOF_VOID_P EQUAL 8)
      string(APPEND _boost_ARCHITECTURE_TAG "64")
    else()
      string(APPEND _boost_ARCHITECTURE_TAG "32")
    endif()
  endif()
endif()

if(Boost_DEBUG)
  message(STATUS "[ ${CMAKE_CURRENT_LIST_FILE}:${CMAKE_CURRENT_LIST_LINE} ] "
    "_boost_RELEASE_ABI_TAG = ${_boost_RELEASE_ABI_TAG}")
  message(STATUS "[ ${CMAKE_CURRENT_LIST_FILE}:${CMAKE_CURRENT_LIST_LINE} ] "
    "_boost_DEBUG_ABI_TAG = ${_boost_DEBUG_ABI_TAG}")
endif()

# ------------------------------------------------------------------------
#  Begin finding boost libraries
# ------------------------------------------------------------------------

set(_Boost_VARS_LIB "")
foreach(c DEBUG RELEASE)
  set(_Boost_VARS_LIB_${c} BOOST_LIBRARYDIR Boost_LIBRARY_DIR_${c})
  list(APPEND _Boost_VARS_LIB ${_Boost_VARS_LIB_${c}})
  _Boost_CHANGE_DETECT(_Boost_CHANGE_LIBDIR_${c} ${_Boost_VARS_DIR} ${_Boost_VARS_LIB_${c}} Boost_INCLUDE_DIR)
  # Clear Boost_LIBRARY_DIR_${c} if it did not change but other input affecting the
  # location did.  We will find a new one based on the new inputs.
  if(_Boost_CHANGE_LIBDIR_${c} AND NOT _Boost_LIBRARY_DIR_${c}_CHANGED)
    unset(Boost_LIBRARY_DIR_${c} CACHE)
  endif()

  # If Boost_LIBRARY_DIR_[RELEASE,DEBUG] is set, prefer its value.
  if(Boost_LIBRARY_DIR_${c})
    set(_boost_LIBRARY_SEARCH_DIRS_${c} ${Boost_LIBRARY_DIR_${c}} NO_DEFAULT_PATH NO_CMAKE_FIND_ROOT_PATH)
  else()
    set(_boost_LIBRARY_SEARCH_DIRS_${c} "")
    if(BOOST_LIBRARYDIR)
      list(APPEND _boost_LIBRARY_SEARCH_DIRS_${c} ${BOOST_LIBRARYDIR})
    elseif(_ENV_BOOST_LIBRARYDIR)
      list(APPEND _boost_LIBRARY_SEARCH_DIRS_${c} ${_ENV_BOOST_LIBRARYDIR})
    endif()

    if(BOOST_ROOT)
      list(APPEND _boost_LIBRARY_SEARCH_DIRS_${c} ${BOOST_ROOT}/lib ${BOOST_ROOT}/stage/lib)
      _Boost_UPDATE_WINDOWS_LIBRARY_SEARCH_DIRS_WITH_PREBUILT_PATHS(_boost_LIBRARY_SEARCH_DIRS_${c} "${BOOST_ROOT}")
    elseif(_ENV_BOOST_ROOT)
      list(APPEND _boost_LIBRARY_SEARCH_DIRS_${c} ${_ENV_BOOST_ROOT}/lib ${_ENV_BOOST_ROOT}/stage/lib)
      _Boost_UPDATE_WINDOWS_LIBRARY_SEARCH_DIRS_WITH_PREBUILT_PATHS(_boost_LIBRARY_SEARCH_DIRS_${c} "${_ENV_BOOST_ROOT}")
    endif()

    list(APPEND _boost_LIBRARY_SEARCH_DIRS_${c}
      ${Boost_INCLUDE_DIR}/lib
      ${Boost_INCLUDE_DIR}/../lib
      ${Boost_INCLUDE_DIR}/stage/lib
      )
    _Boost_UPDATE_WINDOWS_LIBRARY_SEARCH_DIRS_WITH_PREBUILT_PATHS(_boost_LIBRARY_SEARCH_DIRS_${c} "${Boost_INCLUDE_DIR}/..")
    _Boost_UPDATE_WINDOWS_LIBRARY_SEARCH_DIRS_WITH_PREBUILT_PATHS(_boost_LIBRARY_SEARCH_DIRS_${c} "${Boost_INCLUDE_DIR}")
    if( Boost_NO_SYSTEM_PATHS )
      list(APPEND _boost_LIBRARY_SEARCH_DIRS_${c} NO_CMAKE_SYSTEM_PATH NO_SYSTEM_ENVIRONMENT_PATH)
    else()
      foreach(ver ${_boost_TEST_VERSIONS})
        string(REPLACE "." "_" ver "${ver}")
        _Boost_UPDATE_WINDOWS_LIBRARY_SEARCH_DIRS_WITH_PREBUILT_PATHS(_boost_LIBRARY_SEARCH_DIRS_${c} "C:/local/boost_${ver}")
      endforeach()
      _Boost_UPDATE_WINDOWS_LIBRARY_SEARCH_DIRS_WITH_PREBUILT_PATHS(_boost_LIBRARY_SEARCH_DIRS_${c} "C:/boost")
      list(APPEND _boost_LIBRARY_SEARCH_DIRS_${c} PATHS
        C:/boost/lib
        C:/boost
        /sw/local/lib
        )
    endif()
  endif()
endforeach()

if(Boost_DEBUG)
  message(STATUS "[ ${CMAKE_CURRENT_LIST_FILE}:${CMAKE_CURRENT_LIST_LINE} ] "
    "_boost_LIBRARY_SEARCH_DIRS_RELEASE = ${_boost_LIBRARY_SEARCH_DIRS_RELEASE}"
    "_boost_LIBRARY_SEARCH_DIRS_DEBUG   = ${_boost_LIBRARY_SEARCH_DIRS_DEBUG}")
endif()

# Support preference of static libs by adjusting CMAKE_FIND_LIBRARY_SUFFIXES
if( Boost_USE_STATIC_LIBS )
  set( _boost_ORIG_CMAKE_FIND_LIBRARY_SUFFIXES ${CMAKE_FIND_LIBRARY_SUFFIXES})
  if(WIN32)
    list(INSERT CMAKE_FIND_LIBRARY_SUFFIXES 0 .lib .a)
  else()
    set(CMAKE_FIND_LIBRARY_SUFFIXES .a)
  endif()
endif()

# We want to use the tag inline below without risking double dashes
if(_boost_RELEASE_ABI_TAG)
  if(${_boost_RELEASE_ABI_TAG} STREQUAL "-")
    set(_boost_RELEASE_ABI_TAG "")
  endif()
endif()
if(_boost_DEBUG_ABI_TAG)
  if(${_boost_DEBUG_ABI_TAG} STREQUAL "-")
    set(_boost_DEBUG_ABI_TAG "")
  endif()
endif()

# The previous behavior of FindBoost when Boost_USE_STATIC_LIBS was enabled
# on WIN32 was to:
#  1. Search for static libs compiled against a SHARED C++ standard runtime library (use if found)
#  2. Search for static libs compiled against a STATIC C++ standard runtime library (use if found)
# We maintain this behavior since changing it could break people's builds.
# To disable the ambiguous behavior, the user need only
# set Boost_USE_STATIC_RUNTIME either ON or OFF.
set(_boost_STATIC_RUNTIME_WORKAROUND false)
if(WIN32 AND Boost_USE_STATIC_LIBS)
  if(NOT DEFINED Boost_USE_STATIC_RUNTIME)
    set(_boost_STATIC_RUNTIME_WORKAROUND TRUE)
  endif()
endif()

# On versions < 1.35, remove the System library from the considered list
# since it wasn't added until 1.35.
if(Boost_VERSION AND Boost_FIND_COMPONENTS)
   if(Boost_VERSION LESS 103500)
     list(REMOVE_ITEM Boost_FIND_COMPONENTS system)
   endif()
endif()

# Additional components may be required via component dependencies.
# Add any missing components to the list.
_Boost_MISSING_DEPENDENCIES(Boost_FIND_COMPONENTS _Boost_EXTRA_FIND_COMPONENTS)

# If thread is required, get the thread libs as a dependency
if("thread" IN_LIST Boost_FIND_COMPONENTS)
  if(Boost_FIND_QUIETLY)
    set(_Boost_find_quiet QUIET)
  else()
    set(_Boost_find_quiet "")
  endif()
  find_package(Threads ${_Boost_find_quiet})
  unset(_Boost_find_quiet)
endif()

# If the user changed any of our control inputs flush previous results.
if(_Boost_CHANGE_LIBDIR_DEBUG OR _Boost_CHANGE_LIBDIR_RELEASE OR _Boost_CHANGE_LIBNAME)
  foreach(COMPONENT ${_Boost_COMPONENTS_SEARCHED})
    string(TOUPPER ${COMPONENT} UPPERCOMPONENT)
    foreach(c DEBUG RELEASE)
      set(_var Boost_${UPPERCOMPONENT}_LIBRARY_${c})
      unset(${_var} CACHE)
      set(${_var} "${_var}-NOTFOUND")
    endforeach()
  endforeach()
  set(_Boost_COMPONENTS_SEARCHED "")
endif()

foreach(COMPONENT ${Boost_FIND_COMPONENTS})
  string(TOUPPER ${COMPONENT} UPPERCOMPONENT)

  set( _boost_docstring_release "Boost ${COMPONENT} library (release)")
  set( _boost_docstring_debug   "Boost ${COMPONENT} library (debug)")

  # Compute component-specific hints.
  set(_Boost_FIND_LIBRARY_HINTS_FOR_COMPONENT "")
  if(${COMPONENT} STREQUAL "mpi" OR ${COMPONENT} STREQUAL "mpi_python" OR
     ${COMPONENT} STREQUAL "graph_parallel")
    foreach(lib ${MPI_CXX_LIBRARIES} ${MPI_C_LIBRARIES})
      if(IS_ABSOLUTE "${lib}")
        get_filename_component(libdir "${lib}" PATH)
        string(REPLACE "\\" "/" libdir "${libdir}")
        list(APPEND _Boost_FIND_LIBRARY_HINTS_FOR_COMPONENT ${libdir})
      endif()
    endforeach()
  endif()

  # Handle Python version suffixes
  unset(COMPONENT_PYTHON_VERSION_MAJOR)
  unset(COMPONENT_PYTHON_VERSION_MINOR)
  if(${COMPONENT} MATCHES "^(python|mpi_python|numpy)([0-9])\$")
    set(COMPONENT_UNVERSIONED "${CMAKE_MATCH_1}")
    set(COMPONENT_PYTHON_VERSION_MAJOR "${CMAKE_MATCH_2}")
  elseif(${COMPONENT} MATCHES "^(python|mpi_python|numpy)([0-9])\\.?([0-9])\$")
    set(COMPONENT_UNVERSIONED "${CMAKE_MATCH_1}")
    set(COMPONENT_PYTHON_VERSION_MAJOR "${CMAKE_MATCH_2}")
    set(COMPONENT_PYTHON_VERSION_MINOR "${CMAKE_MATCH_3}")
  endif()

  unset(_Boost_FIND_LIBRARY_HINTS_FOR_COMPONENT_NAME)
  if (COMPONENT_PYTHON_VERSION_MINOR)
    # Boost >= 1.67
    list(APPEND _Boost_FIND_LIBRARY_HINTS_FOR_COMPONENT_NAME "${COMPONENT_UNVERSIONED}${COMPONENT_PYTHON_VERSION_MAJOR}${COMPONENT_PYTHON_VERSION_MINOR}")
    # Debian/Ubuntu (Some versions omit the 2 and/or 3 from the suffix)
    list(APPEND _Boost_FIND_LIBRARY_HINTS_FOR_COMPONENT_NAME "${COMPONENT_UNVERSIONED}${COMPONENT_PYTHON_VERSION_MAJOR}-py${COMPONENT_PYTHON_VERSION_MAJOR}${COMPONENT_PYTHON_VERSION_MINOR}")
    list(APPEND _Boost_FIND_LIBRARY_HINTS_FOR_COMPONENT_NAME "${COMPONENT_UNVERSIONED}-py${COMPONENT_PYTHON_VERSION_MAJOR}${COMPONENT_PYTHON_VERSION_MINOR}")
    # Gentoo
    list(APPEND _Boost_FIND_LIBRARY_HINTS_FOR_COMPONENT_NAME "${COMPONENT_UNVERSIONED}-${COMPONENT_PYTHON_VERSION_MAJOR}${COMPONENT_PYTHON_VERSION_MINOR}")
    # RPMs
    list(APPEND _Boost_FIND_LIBRARY_HINTS_FOR_COMPONENT_NAME "${COMPONENT_UNVERSIONED}-${COMPONENT_PYTHON_VERSION_MAJOR}${COMPONENT_PYTHON_VERSION_MINOR}")
  endif()
  if (COMPONENT_PYTHON_VERSION_MAJOR AND NOT COMPONENT_PYTHON_VERSION_MINOR)
    # Boost < 1.67
    list(APPEND _Boost_FIND_LIBRARY_HINTS_FOR_COMPONENT_NAME "${COMPONENT_UNVERSIONED}${COMPONENT_PYTHON_VERSION_MAJOR}")
  endif()

  # Consolidate and report component-specific hints.
  if(_Boost_FIND_LIBRARY_HINTS_FOR_COMPONENT_NAME)
    list(REMOVE_DUPLICATES _Boost_FIND_LIBRARY_HINTS_FOR_COMPONENT_NAME)
    if(Boost_DEBUG)
      message(STATUS "[ ${CMAKE_CURRENT_LIST_FILE}:${CMAKE_CURRENT_LIST_LINE} ] "
        "Component-specific library search names for ${COMPONENT_NAME}: "
        "${_Boost_FIND_LIBRARY_HINTS_FOR_COMPONENT_NAME}")
    endif()
  endif()
  if(_Boost_FIND_LIBRARY_HINTS_FOR_COMPONENT)
    list(REMOVE_DUPLICATES _Boost_FIND_LIBRARY_HINTS_FOR_COMPONENT)
    if(Boost_DEBUG)
      message(STATUS "[ ${CMAKE_CURRENT_LIST_FILE}:${CMAKE_CURRENT_LIST_LINE} ] "
        "Component-specific library search paths for ${COMPONENT}: "
        "${_Boost_FIND_LIBRARY_HINTS_FOR_COMPONENT}")
    endif()
  endif()

  #
  # Find headers
  #
  _Boost_COMPONENT_HEADERS("${COMPONENT}" Boost_${UPPERCOMPONENT}_HEADER_NAME)
  # Look for a standard boost header file.
  if(Boost_${UPPERCOMPONENT}_HEADER_NAME)
    if(EXISTS "${Boost_INCLUDE_DIR}/${Boost_${UPPERCOMPONENT}_HEADER_NAME}")
      set(Boost_${UPPERCOMPONENT}_HEADER ON)
    else()
      set(Boost_${UPPERCOMPONENT}_HEADER OFF)
    endif()
  else()
    set(Boost_${UPPERCOMPONENT}_HEADER ON)
    message(WARNING "No header defined for ${COMPONENT}; skipping header check")
  endif()

  #
  # Find RELEASE libraries
  #
  unset(_boost_RELEASE_NAMES)
  foreach(component IN LISTS _Boost_FIND_LIBRARY_HINTS_FOR_COMPONENT_NAME COMPONENT)
    foreach(compiler IN LISTS _boost_COMPILER)
      list(APPEND _boost_RELEASE_NAMES
        ${Boost_LIB_PREFIX}${Boost_NAMESPACE}_${component}${compiler}${_boost_MULTITHREADED}${_boost_RELEASE_ABI_TAG}${_boost_ARCHITECTURE_TAG}-${Boost_LIB_VERSION}
        ${Boost_LIB_PREFIX}${Boost_NAMESPACE}_${component}${compiler}${_boost_MULTITHREADED}${_boost_RELEASE_ABI_TAG}${_boost_ARCHITECTURE_TAG}
        ${Boost_LIB_PREFIX}${Boost_NAMESPACE}_${component}${compiler}${_boost_MULTITHREADED}${_boost_RELEASE_ABI_TAG} )
    endforeach()
    list(APPEND _boost_RELEASE_NAMES
      ${Boost_LIB_PREFIX}${Boost_NAMESPACE}_${component}${_boost_MULTITHREADED}${_boost_RELEASE_ABI_TAG}${_boost_ARCHITECTURE_TAG}-${Boost_LIB_VERSION}
      ${Boost_LIB_PREFIX}${Boost_NAMESPACE}_${component}${_boost_MULTITHREADED}${_boost_RELEASE_ABI_TAG}${_boost_ARCHITECTURE_TAG}
      ${Boost_LIB_PREFIX}${Boost_NAMESPACE}_${component}${_boost_MULTITHREADED}${_boost_RELEASE_ABI_TAG}
      ${Boost_LIB_PREFIX}${Boost_NAMESPACE}_${component}${_boost_MULTITHREADED}
      ${Boost_LIB_PREFIX}${Boost_NAMESPACE}_${component} )
    if(_boost_STATIC_RUNTIME_WORKAROUND)
      set(_boost_RELEASE_STATIC_ABI_TAG "-s${_boost_RELEASE_ABI_TAG}")
      foreach(compiler IN LISTS _boost_COMPILER)
        list(APPEND _boost_RELEASE_NAMES
          ${Boost_LIB_PREFIX}${Boost_NAMESPACE}_${component}${compiler}${_boost_MULTITHREADED}${_boost_RELEASE_STATIC_ABI_TAG}${_boost_ARCHITECTURE_TAG}-${Boost_LIB_VERSION}
          ${Boost_LIB_PREFIX}${Boost_NAMESPACE}_${component}${compiler}${_boost_MULTITHREADED}${_boost_RELEASE_STATIC_ABI_TAG}${_boost_ARCHITECTURE_TAG}
          ${Boost_LIB_PREFIX}${Boost_NAMESPACE}_${component}${compiler}${_boost_MULTITHREADED}${_boost_RELEASE_STATIC_ABI_TAG} )
      endforeach()
      list(APPEND _boost_RELEASE_NAMES
        ${Boost_LIB_PREFIX}${Boost_NAMESPACE}_${component}${_boost_MULTITHREADED}${_boost_RELEASE_STATIC_ABI_TAG}${_boost_ARCHITECTURE_TAG}-${Boost_LIB_VERSION}
        ${Boost_LIB_PREFIX}${Boost_NAMESPACE}_${component}${_boost_MULTITHREADED}${_boost_RELEASE_STATIC_ABI_TAG}${_boost_ARCHITECTURE_TAG}
        ${Boost_LIB_PREFIX}${Boost_NAMESPACE}_${component}${_boost_MULTITHREADED}${_boost_RELEASE_STATIC_ABI_TAG} )
    endif()
  endforeach()
  if(Boost_THREADAPI AND ${COMPONENT} STREQUAL "thread")
    _Boost_PREPEND_LIST_WITH_THREADAPI(_boost_RELEASE_NAMES ${_boost_RELEASE_NAMES})
  endif()
  if(Boost_DEBUG)
    message(STATUS "[ ${CMAKE_CURRENT_LIST_FILE}:${CMAKE_CURRENT_LIST_LINE} ] "
                   "Searching for ${UPPERCOMPONENT}_LIBRARY_RELEASE: ${_boost_RELEASE_NAMES}")
  endif()

  # if Boost_LIBRARY_DIR_RELEASE is not defined,
  # but Boost_LIBRARY_DIR_DEBUG is, look there first for RELEASE libs
  if(NOT Boost_LIBRARY_DIR_RELEASE AND Boost_LIBRARY_DIR_DEBUG)
    list(INSERT _boost_LIBRARY_SEARCH_DIRS_RELEASE 0 ${Boost_LIBRARY_DIR_DEBUG})
  endif()

  # Avoid passing backslashes to _Boost_FIND_LIBRARY due to macro re-parsing.
  string(REPLACE "\\" "/" _boost_LIBRARY_SEARCH_DIRS_tmp "${_boost_LIBRARY_SEARCH_DIRS_RELEASE}")

  if(Boost_USE_RELEASE_LIBS)
    _Boost_FIND_LIBRARY(Boost_${UPPERCOMPONENT}_LIBRARY_RELEASE RELEASE
      NAMES ${_boost_RELEASE_NAMES}
      HINTS ${_boost_LIBRARY_SEARCH_DIRS_tmp}
      NAMES_PER_DIR
      DOC "${_boost_docstring_release}"
      )
  endif()

  #
  # Find DEBUG libraries
  #
  unset(_boost_DEBUG_NAMES)
  foreach(component IN LISTS _Boost_FIND_LIBRARY_HINTS_FOR_COMPONENT_NAME COMPONENT)
    foreach(compiler IN LISTS _boost_COMPILER)
      list(APPEND _boost_DEBUG_NAMES
        ${Boost_LIB_PREFIX}${Boost_NAMESPACE}_${component}${compiler}${_boost_MULTITHREADED}${_boost_DEBUG_ABI_TAG}${_boost_ARCHITECTURE_TAG}-${Boost_LIB_VERSION}
        ${Boost_LIB_PREFIX}${Boost_NAMESPACE}_${component}${compiler}${_boost_MULTITHREADED}${_boost_DEBUG_ABI_TAG}${_boost_ARCHITECTURE_TAG}
        ${Boost_LIB_PREFIX}${Boost_NAMESPACE}_${component}${compiler}${_boost_MULTITHREADED}${_boost_DEBUG_ABI_TAG} )
    endforeach()
    list(APPEND _boost_DEBUG_NAMES
      ${Boost_LIB_PREFIX}${Boost_NAMESPACE}_${component}${_boost_MULTITHREADED}${_boost_DEBUG_ABI_TAG}${_boost_ARCHITECTURE_TAG}-${Boost_LIB_VERSION}
      ${Boost_LIB_PREFIX}${Boost_NAMESPACE}_${component}${_boost_MULTITHREADED}${_boost_DEBUG_ABI_TAG}${_boost_ARCHITECTURE_TAG}
      ${Boost_LIB_PREFIX}${Boost_NAMESPACE}_${component}${_boost_MULTITHREADED}${_boost_DEBUG_ABI_TAG}
      ${Boost_LIB_PREFIX}${Boost_NAMESPACE}_${component}${_boost_MULTITHREADED}
      ${Boost_LIB_PREFIX}${Boost_NAMESPACE}_${component} )
    if(_boost_STATIC_RUNTIME_WORKAROUND)
      set(_boost_DEBUG_STATIC_ABI_TAG "-s${_boost_DEBUG_ABI_TAG}")
      foreach(compiler IN LISTS _boost_COMPILER)
        list(APPEND _boost_DEBUG_NAMES
          ${Boost_LIB_PREFIX}${Boost_NAMESPACE}_${component}${compiler}${_boost_MULTITHREADED}${_boost_DEBUG_STATIC_ABI_TAG}${_boost_ARCHITECTURE_TAG}-${Boost_LIB_VERSION}
          ${Boost_LIB_PREFIX}${Boost_NAMESPACE}_${component}${compiler}${_boost_MULTITHREADED}${_boost_DEBUG_STATIC_ABI_TAG}${_boost_ARCHITECTURE_TAG}
          ${Boost_LIB_PREFIX}${Boost_NAMESPACE}_${component}${compiler}${_boost_MULTITHREADED}${_boost_DEBUG_STATIC_ABI_TAG} )
      endforeach()
      list(APPEND _boost_DEBUG_NAMES
        ${Boost_LIB_PREFIX}${Boost_NAMESPACE}_${component}${_boost_MULTITHREADED}${_boost_DEBUG_STATIC_ABI_TAG}${_boost_ARCHITECTURE_TAG}-${Boost_LIB_VERSION}
        ${Boost_LIB_PREFIX}${Boost_NAMESPACE}_${component}${_boost_MULTITHREADED}${_boost_DEBUG_STATIC_ABI_TAG}${_boost_ARCHITECTURE_TAG}
        ${Boost_LIB_PREFIX}${Boost_NAMESPACE}_${component}${_boost_MULTITHREADED}${_boost_DEBUG_STATIC_ABI_TAG} )
    endif()
  endforeach()
  if(Boost_THREADAPI AND ${COMPONENT} STREQUAL "thread")
     _Boost_PREPEND_LIST_WITH_THREADAPI(_boost_DEBUG_NAMES ${_boost_DEBUG_NAMES})
  endif()
  if(Boost_DEBUG)
    message(STATUS "[ ${CMAKE_CURRENT_LIST_FILE}:${CMAKE_CURRENT_LIST_LINE} ] "
                   "Searching for ${UPPERCOMPONENT}_LIBRARY_DEBUG: ${_boost_DEBUG_NAMES}")
  endif()

  # if Boost_LIBRARY_DIR_DEBUG is not defined,
  # but Boost_LIBRARY_DIR_RELEASE is, look there first for DEBUG libs
  if(NOT Boost_LIBRARY_DIR_DEBUG AND Boost_LIBRARY_DIR_RELEASE)
    list(INSERT _boost_LIBRARY_SEARCH_DIRS_DEBUG 0 ${Boost_LIBRARY_DIR_RELEASE})
  endif()

  # Avoid passing backslashes to _Boost_FIND_LIBRARY due to macro re-parsing.
  string(REPLACE "\\" "/" _boost_LIBRARY_SEARCH_DIRS_tmp "${_boost_LIBRARY_SEARCH_DIRS_DEBUG}")

  if(Boost_USE_DEBUG_LIBS)
    _Boost_FIND_LIBRARY(Boost_${UPPERCOMPONENT}_LIBRARY_DEBUG DEBUG
      NAMES ${_boost_DEBUG_NAMES}
      HINTS ${_boost_LIBRARY_SEARCH_DIRS_tmp}
      NAMES_PER_DIR
      DOC "${_boost_docstring_debug}"
      )
  endif ()

  if(Boost_REALPATH)
    _Boost_SWAP_WITH_REALPATH(Boost_${UPPERCOMPONENT}_LIBRARY_RELEASE "${_boost_docstring_release}")
    _Boost_SWAP_WITH_REALPATH(Boost_${UPPERCOMPONENT}_LIBRARY_DEBUG   "${_boost_docstring_debug}"  )
  endif()

  _Boost_ADJUST_LIB_VARS(${UPPERCOMPONENT})

  # Check if component requires some compiler features
  _Boost_COMPILER_FEATURES(${COMPONENT} _Boost_${UPPERCOMPONENT}_COMPILER_FEATURES)

endforeach()

# Restore the original find library ordering
if( Boost_USE_STATIC_LIBS )
  set(CMAKE_FIND_LIBRARY_SUFFIXES ${_boost_ORIG_CMAKE_FIND_LIBRARY_SUFFIXES})
endif()

# ------------------------------------------------------------------------
#  End finding boost libraries
# ------------------------------------------------------------------------

set(Boost_INCLUDE_DIRS ${Boost_INCLUDE_DIR})
set(Boost_LIBRARY_DIRS)
if(Boost_LIBRARY_DIR_RELEASE)
  list(APPEND Boost_LIBRARY_DIRS ${Boost_LIBRARY_DIR_RELEASE})
endif()
if(Boost_LIBRARY_DIR_DEBUG)
  list(APPEND Boost_LIBRARY_DIRS ${Boost_LIBRARY_DIR_DEBUG})
endif()
if(Boost_LIBRARY_DIRS)
  list(REMOVE_DUPLICATES Boost_LIBRARY_DIRS)
endif()

# The above setting of Boost_FOUND was based only on the header files.
# Update it for the requested component libraries.
if(Boost_FOUND)
  # The headers were found.  Check for requested component libs.
  set(_boost_CHECKED_COMPONENT FALSE)
  set(_Boost_MISSING_COMPONENTS "")
  foreach(COMPONENT ${Boost_FIND_COMPONENTS})
    string(TOUPPER ${COMPONENT} UPPERCOMPONENT)
    set(_boost_CHECKED_COMPONENT TRUE)
    if(NOT Boost_${UPPERCOMPONENT}_FOUND AND Boost_FIND_REQUIRED_${COMPONENT})
      list(APPEND _Boost_MISSING_COMPONENTS ${COMPONENT})
    endif()
  endforeach()
  if(_Boost_MISSING_COMPONENTS AND _Boost_EXTRA_FIND_COMPONENTS)
    # Optional indirect dependencies are not counted as missing.
    list(REMOVE_ITEM _Boost_MISSING_COMPONENTS ${_Boost_EXTRA_FIND_COMPONENTS})
  endif()

  if(Boost_DEBUG)
    message(STATUS "[ ${CMAKE_CURRENT_LIST_FILE}:${CMAKE_CURRENT_LIST_LINE} ] Boost_FOUND = ${Boost_FOUND}")
  endif()

  if (_Boost_MISSING_COMPONENTS)
    set(Boost_FOUND 0)
    # We were unable to find some libraries, so generate a sensible
    # error message that lists the libraries we were unable to find.
    string(APPEND Boost_ERROR_REASON
      "\nCould not find the following")
    if(Boost_USE_STATIC_LIBS)
      string(APPEND Boost_ERROR_REASON " static")
    endif()
    string(APPEND Boost_ERROR_REASON
      " Boost libraries:\n")
    foreach(COMPONENT ${_Boost_MISSING_COMPONENTS})
      string(TOUPPER ${COMPONENT} UPPERCOMPONENT)
      string(APPEND Boost_ERROR_REASON
        "        ${Boost_NAMESPACE}_${COMPONENT}${Boost_ERROR_REASON_${UPPERCOMPONENT}}\n")
    endforeach()

    list(LENGTH Boost_FIND_COMPONENTS Boost_NUM_COMPONENTS_WANTED)
    list(LENGTH _Boost_MISSING_COMPONENTS Boost_NUM_MISSING_COMPONENTS)
    if (${Boost_NUM_COMPONENTS_WANTED} EQUAL ${Boost_NUM_MISSING_COMPONENTS})
      string(APPEND Boost_ERROR_REASON
        "No Boost libraries were found. You may need to set BOOST_LIBRARYDIR to the directory containing Boost libraries or BOOST_ROOT to the location of Boost.")
    else ()
      string(APPEND Boost_ERROR_REASON
        "Some (but not all) of the required Boost libraries were found. You may need to install these additional Boost libraries. Alternatively, set BOOST_LIBRARYDIR to the directory containing Boost libraries or BOOST_ROOT to the location of Boost.")
    endif ()
  endif ()

  if( NOT Boost_LIBRARY_DIRS AND NOT _boost_CHECKED_COMPONENT )
    # Compatibility Code for backwards compatibility with CMake
    # 2.4's FindBoost module.

    # Look for the boost library path.
    # Note that the user may not have installed any libraries
    # so it is quite possible the Boost_LIBRARY_DIRS may not exist.
    set(_boost_LIB_DIR ${Boost_INCLUDE_DIR})

    if("${_boost_LIB_DIR}" MATCHES "boost-[0-9]+")
      get_filename_component(_boost_LIB_DIR ${_boost_LIB_DIR} PATH)
    endif()

    if("${_boost_LIB_DIR}" MATCHES "/include$")
      # Strip off the trailing "/include" in the path.
      get_filename_component(_boost_LIB_DIR ${_boost_LIB_DIR} PATH)
    endif()

    if(EXISTS "${_boost_LIB_DIR}/lib")
      string(APPEND _boost_LIB_DIR /lib)
    elseif(EXISTS "${_boost_LIB_DIR}/stage/lib")
      string(APPEND _boost_LIB_DIR "/stage/lib")
    else()
      set(_boost_LIB_DIR "")
    endif()

    if(_boost_LIB_DIR AND EXISTS "${_boost_LIB_DIR}")
      set(Boost_LIBRARY_DIRS ${_boost_LIB_DIR})
    endif()

  endif()
else()
  # Boost headers were not found so no components were found.
  foreach(COMPONENT ${Boost_FIND_COMPONENTS})
    string(TOUPPER ${COMPONENT} UPPERCOMPONENT)
    set(Boost_${UPPERCOMPONENT}_FOUND 0)
  endforeach()
endif()

# ------------------------------------------------------------------------
#  Add imported targets
# ------------------------------------------------------------------------

if(Boost_FOUND)
  # For header-only libraries
  if(NOT TARGET Boost::boost)
    add_library(Boost::boost INTERFACE IMPORTED)
    if(Boost_INCLUDE_DIRS)
      set_target_properties(Boost::boost PROPERTIES
        INTERFACE_INCLUDE_DIRECTORIES "${Boost_INCLUDE_DIRS}")
    endif()
  endif()

  foreach(COMPONENT ${Boost_FIND_COMPONENTS})
    if(_Boost_IMPORTED_TARGETS AND NOT TARGET Boost::${COMPONENT})
      string(TOUPPER ${COMPONENT} UPPERCOMPONENT)
      if(Boost_${UPPERCOMPONENT}_FOUND)
        if(Boost_USE_STATIC_LIBS)
          add_library(Boost::${COMPONENT} STATIC IMPORTED)
        else()
          # Even if Boost_USE_STATIC_LIBS is OFF, we might have static
          # libraries as a result.
          add_library(Boost::${COMPONENT} UNKNOWN IMPORTED)
        endif()
        if(Boost_INCLUDE_DIRS)
          set_target_properties(Boost::${COMPONENT} PROPERTIES
            INTERFACE_INCLUDE_DIRECTORIES "${Boost_INCLUDE_DIRS}")
        endif()
        if(EXISTS "${Boost_${UPPERCOMPONENT}_LIBRARY}")
          set_target_properties(Boost::${COMPONENT} PROPERTIES
            IMPORTED_LINK_INTERFACE_LANGUAGES "CXX"
            IMPORTED_LOCATION "${Boost_${UPPERCOMPONENT}_LIBRARY}")
        endif()
        if(EXISTS "${Boost_${UPPERCOMPONENT}_LIBRARY_RELEASE}")
          set_property(TARGET Boost::${COMPONENT} APPEND PROPERTY
            IMPORTED_CONFIGURATIONS RELEASE)
          set_target_properties(Boost::${COMPONENT} PROPERTIES
            IMPORTED_LINK_INTERFACE_LANGUAGES_RELEASE "CXX"
            IMPORTED_LOCATION_RELEASE "${Boost_${UPPERCOMPONENT}_LIBRARY_RELEASE}")
        endif()
        if(EXISTS "${Boost_${UPPERCOMPONENT}_LIBRARY_DEBUG}")
          set_property(TARGET Boost::${COMPONENT} APPEND PROPERTY
            IMPORTED_CONFIGURATIONS DEBUG)
          set_target_properties(Boost::${COMPONENT} PROPERTIES
            IMPORTED_LINK_INTERFACE_LANGUAGES_DEBUG "CXX"
            IMPORTED_LOCATION_DEBUG "${Boost_${UPPERCOMPONENT}_LIBRARY_DEBUG}")
        endif()
        if(_Boost_${UPPERCOMPONENT}_DEPENDENCIES)
          unset(_Boost_${UPPERCOMPONENT}_TARGET_DEPENDENCIES)
          foreach(dep ${_Boost_${UPPERCOMPONENT}_DEPENDENCIES})
            list(APPEND _Boost_${UPPERCOMPONENT}_TARGET_DEPENDENCIES Boost::${dep})
          endforeach()
          if(COMPONENT STREQUAL "thread")
            list(APPEND _Boost_${UPPERCOMPONENT}_TARGET_DEPENDENCIES Threads::Threads)
          endif()
          set_target_properties(Boost::${COMPONENT} PROPERTIES
            INTERFACE_LINK_LIBRARIES "${_Boost_${UPPERCOMPONENT}_TARGET_DEPENDENCIES}")
        endif()
        if(_Boost_${UPPERCOMPONENT}_COMPILER_FEATURES)
          set_target_properties(Boost::${COMPONENT} PROPERTIES
            INTERFACE_COMPILE_FEATURES "${_Boost_${UPPERCOMPONENT}_COMPILER_FEATURES}")
        endif()
      endif()
    endif()
  endforeach()
endif()

# ------------------------------------------------------------------------
#  Notification to end user about what was found
# ------------------------------------------------------------------------

set(Boost_LIBRARIES "")
if(Boost_FOUND)
  if(NOT Boost_FIND_QUIETLY)
    message(STATUS "Boost version: ${Boost_MAJOR_VERSION}.${Boost_MINOR_VERSION}.${Boost_SUBMINOR_VERSION}")
    if(Boost_FIND_COMPONENTS)
      message(STATUS "Found the following Boost libraries:")
    endif()
  endif()
  foreach( COMPONENT  ${Boost_FIND_COMPONENTS} )
    string( TOUPPER ${COMPONENT} UPPERCOMPONENT )
    if( Boost_${UPPERCOMPONENT}_FOUND )
      if(NOT Boost_FIND_QUIETLY)
        message (STATUS "  ${COMPONENT}")
      endif()
      list(APPEND Boost_LIBRARIES ${Boost_${UPPERCOMPONENT}_LIBRARY})
      if(COMPONENT STREQUAL "thread")
        list(APPEND Boost_LIBRARIES ${CMAKE_THREAD_LIBS_INIT})
      endif()
    endif()
  endforeach()
else()
  if(Boost_FIND_REQUIRED)
    message(SEND_ERROR "Unable to find the requested Boost libraries.\n${Boost_ERROR_REASON}")
  else()
    if(NOT Boost_FIND_QUIETLY)
      # we opt not to automatically output Boost_ERROR_REASON here as
      # it could be quite lengthy and somewhat imposing in its requests
      # Since Boost is not always a required dependency we'll leave this
      # up to the end-user.
      if(Boost_DEBUG OR Boost_DETAILED_FAILURE_MSG)
        message(STATUS "Could NOT find Boost\n${Boost_ERROR_REASON}")
      else()
        message(STATUS "Could NOT find Boost")
      endif()
    endif()
  endif()
endif()

# Configure display of cache entries in GUI.
foreach(v BOOSTROOT BOOST_ROOT ${_Boost_VARS_INC} ${_Boost_VARS_LIB})
  get_property(_type CACHE ${v} PROPERTY TYPE)
  if(_type)
    set_property(CACHE ${v} PROPERTY ADVANCED 1)
    if("x${_type}" STREQUAL "xUNINITIALIZED")
      if("x${v}" STREQUAL "xBoost_ADDITIONAL_VERSIONS")
        set_property(CACHE ${v} PROPERTY TYPE STRING)
      else()
        set_property(CACHE ${v} PROPERTY TYPE PATH)
      endif()
    endif()
  endif()
endforeach()

# Record last used values of input variables so we can
# detect on the next run if the user changed them.
foreach(v
    ${_Boost_VARS_INC} ${_Boost_VARS_LIB}
    ${_Boost_VARS_DIR} ${_Boost_VARS_NAME}
    )
  if(DEFINED ${v})
    set(_${v}_LAST "${${v}}" CACHE INTERNAL "Last used ${v} value.")
  else()
    unset(_${v}_LAST CACHE)
  endif()
endforeach()

# Maintain a persistent list of components requested anywhere since
# the last flush.
set(_Boost_COMPONENTS_SEARCHED "${_Boost_COMPONENTS_SEARCHED}")
list(APPEND _Boost_COMPONENTS_SEARCHED ${Boost_FIND_COMPONENTS})
list(REMOVE_DUPLICATES _Boost_COMPONENTS_SEARCHED)
list(SORT _Boost_COMPONENTS_SEARCHED)
set(_Boost_COMPONENTS_SEARCHED "${_Boost_COMPONENTS_SEARCHED}"
  CACHE INTERNAL "Components requested for this build tree.")

# Restore project's policies
cmake_policy(POP)