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_MACRO    - BOOST_VERSION value from boost/version.hpp
  Boost_VERSION_STRING   - Boost version number in x.y.z format
  Boost_VERSION          - if CMP0093 NEW => same as Boost_VERSION_STRING
                           if CMP0093 OLD or unset => same as Boost_VERSION_MACRO
  Boost_LIB_VERSION      - Version string appended to library filenames
  Boost_VERSION_MAJOR    - Boost major version number (X in X.y.z)
                           alias: Boost_MAJOR_VERSION
  Boost_VERSION_MINOR    - Boost minor version number (Y in x.Y.z)
                           alias: Boost_MINOR_VERSION
  Boost_VERSION_PATCH    - Boost subminor version number (Z in x.y.Z)
                           alias: Boost_SUBMINOR_VERSION
  Boost_VERSION_COUNT    - Amount of version components (3)
  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::headers                - Target for header-only dependencies
                                  (Boost include directory)
                                  alias: Boost::boost
  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 :command:`find_package` and if
``Boost::system`` is not added to :command:`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
:command:`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_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 or from Boost 1.70.0 on
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.
#]=======================================================================]

# The FPHSA helper provides standard way of reporting final search results to
# the user including the version and component checks.
include(${CMAKE_CURRENT_LIST_DIR}/FindPackageHandleStandardArgs.cmake)

# Save project's policies
cmake_policy(PUSH)
cmake_policy(SET CMP0057 NEW) # if IN_LIST
cmake_policy(SET CMP0102 NEW) # if mark_as_advanced(non_cache_var)

function(_boost_get_existing_target component target_var)
  set(names "${component}")
  if(component MATCHES "^([a-z_]*)(python|numpy)([1-9])\\.?([0-9])?$")
    # handle pythonXY and numpyXY versioned components and also python X.Y, mpi_python etc.
    list(APPEND names
      "${CMAKE_MATCH_1}${CMAKE_MATCH_2}" # python
      "${CMAKE_MATCH_1}${CMAKE_MATCH_2}${CMAKE_MATCH_3}" # pythonX
      "${CMAKE_MATCH_1}${CMAKE_MATCH_2}${CMAKE_MATCH_3}${CMAKE_MATCH_4}" #pythonXY
    )
  endif()
  # https://github.com/boost-cmake/boost-cmake uses boost::file_system etc.
  # So handle similar constructions of target names
  string(TOLOWER "${component}" lower_component)
  list(APPEND names "${lower_component}")
  foreach(prefix Boost boost)
    foreach(name IN LISTS names)
      if(TARGET "${prefix}::${name}")
        # The target may be an INTERFACE library that wraps around a single other
        # target for compatibility.  Unwrap this layer so we can extract real info.
        if("${name}" MATCHES "^(python|numpy|mpi_python)([1-9])([0-9])$")
          set(name_nv "${CMAKE_MATCH_1}")
          if(TARGET "${prefix}::${name_nv}")
            get_property(type TARGET "${prefix}::${name}" PROPERTY TYPE)
            if(type STREQUAL "INTERFACE_LIBRARY")
              get_property(lib TARGET "${prefix}::${name}" PROPERTY INTERFACE_LINK_LIBRARIES)
              if("${lib}" STREQUAL "${prefix}::${name_nv}")
                set(${target_var} "${prefix}::${name_nv}" PARENT_SCOPE)
                return()
              endif()
            endif()
          endif()
        endif()
        set(${target_var} "${prefix}::${name}" PARENT_SCOPE)
        return()
      endif()
    endforeach()
  endforeach()
  set(${target_var} "" PARENT_SCOPE)
endfunction()

function(_boost_get_canonical_target_name component target_var)
  string(TOLOWER "${component}" component)
  if(component MATCHES "^([a-z_]*)(python|numpy)([1-9])\\.?([0-9])?$")
    # handle pythonXY and numpyXY versioned components and also python X.Y, mpi_python etc.
    set(${target_var} "Boost::${CMAKE_MATCH_1}${CMAKE_MATCH_2}" PARENT_SCOPE)
  else()
    set(${target_var} "Boost::${component}" PARENT_SCOPE)
  endif()
endfunction()

macro(_boost_set_in_parent_scope name value)
  # Set a variable in parent scope and make it visibile in current scope
  set(${name} "${value}" PARENT_SCOPE)
  set(${name} "${value}")
endmacro()

macro(_boost_set_if_unset name value)
  if(NOT ${name})
    _boost_set_in_parent_scope(${name} "${value}")
  endif()
endmacro()

macro(_boost_set_cache_if_unset name value)
  if(NOT ${name})
    set(${name} "${value}" CACHE STRING "" FORCE)
  endif()
endmacro()

macro(_boost_append_include_dir target)
  get_target_property(inc "${target}" INTERFACE_INCLUDE_DIRECTORIES)
  if(inc)
    list(APPEND include_dirs "${inc}")
  endif()
endmacro()

function(_boost_set_legacy_variables_from_config)
  # Set legacy variables for compatibility if not set
  set(include_dirs "")
  set(library_dirs "")
  set(libraries "")
  # Header targets Boost::headers or Boost::boost
  foreach(comp headers boost)
    _boost_get_existing_target(${comp} target)
    if(target)
      _boost_append_include_dir("${target}")
    endif()
  endforeach()
  # Library targets
  foreach(comp IN LISTS Boost_FIND_COMPONENTS)
    string(TOUPPER ${comp} uppercomp)
    # Overwrite if set
    _boost_set_in_parent_scope(Boost_${uppercomp}_FOUND "${Boost_${comp}_FOUND}")
    if(Boost_${comp}_FOUND)
      _boost_get_existing_target(${comp} target)
      if(NOT target)
        if(Boost_DEBUG OR Boost_VERBOSE)
          message(WARNING "Could not find imported target for required component '${comp}'. Legacy variables for this component might be missing. Refer to the documentation of your Boost installation for help on variables to use.")
        endif()
        continue()
      endif()
      _boost_append_include_dir("${target}")
      _boost_set_if_unset(Boost_${uppercomp}_LIBRARY "${target}")
      _boost_set_if_unset(Boost_${uppercomp}_LIBRARIES "${target}") # Very old legacy variable
      list(APPEND libraries "${target}")
      get_property(type TARGET "${target}" PROPERTY TYPE)
      if(NOT type STREQUAL "INTERFACE_LIBRARY")
        foreach(cfg RELEASE DEBUG)
          get_target_property(lib ${target} IMPORTED_LOCATION_${cfg})
          if(lib)
            get_filename_component(lib_dir "${lib}" DIRECTORY)
            list(APPEND library_dirs ${lib_dir})
            _boost_set_cache_if_unset(Boost_${uppercomp}_LIBRARY_${cfg} "${lib}")
          endif()
        endforeach()
      elseif(Boost_DEBUG OR Boost_VERBOSE)
        # For projects using only the Boost::* targets this warning can be safely ignored.
        message(WARNING "Imported target '${target}' for required component '${comp}' has no artifact. Legacy variables for this component might be missing. Refer to the documentation of your Boost installation for help on variables to use.")
      endif()
      _boost_get_canonical_target_name("${comp}" canonical_target)
      if(NOT TARGET "${canonical_target}")
        add_library("${canonical_target}" INTERFACE IMPORTED)
        target_link_libraries("${canonical_target}" INTERFACE "${target}")
      endif()
    endif()
  endforeach()
  list(REMOVE_DUPLICATES include_dirs)
  list(REMOVE_DUPLICATES library_dirs)
  _boost_set_if_unset(Boost_INCLUDE_DIRS "${include_dirs}")
  _boost_set_if_unset(Boost_LIBRARY_DIRS "${library_dirs}")
  _boost_set_if_unset(Boost_LIBRARIES "${libraries}")
  _boost_set_if_unset(Boost_VERSION_STRING "${Boost_VERSION_MAJOR}.${Boost_VERSION_MINOR}.${Boost_VERSION_PATCH}")
  find_path(Boost_INCLUDE_DIR
    NAMES boost/version.hpp boost/config.hpp
    HINTS ${Boost_INCLUDE_DIRS}
    NO_DEFAULT_PATH
  )
  if(NOT Boost_VERSION_MACRO OR NOT Boost_LIB_VERSION)
    set(version_file ${Boost_INCLUDE_DIR}/boost/version.hpp)
    if(EXISTS "${version_file}")
      file(STRINGS "${version_file}" contents REGEX "#define BOOST_(LIB_)?VERSION ")
      if(contents MATCHES "#define BOOST_VERSION ([0-9]+)")
        _boost_set_if_unset(Boost_VERSION_MACRO "${CMAKE_MATCH_1}")
      endif()
      if(contents MATCHES "#define BOOST_LIB_VERSION \"([0-9_]+)\"")
        _boost_set_if_unset(Boost_LIB_VERSION "${CMAKE_MATCH_1}")
      endif()
    endif()
  endif()
  _boost_set_if_unset(Boost_MAJOR_VERSION ${Boost_VERSION_MAJOR})
  _boost_set_if_unset(Boost_MINOR_VERSION ${Boost_VERSION_MINOR})
  _boost_set_if_unset(Boost_SUBMINOR_VERSION ${Boost_VERSION_PATCH})
  if(WIN32)
    _boost_set_if_unset(Boost_LIB_DIAGNOSTIC_DEFINITIONS "-DBOOST_LIB_DIAGNOSTIC")
  endif()
  if(NOT TARGET Boost::headers)
    add_library(Boost::headers INTERFACE IMPORTED)
    target_include_directories(Boost::headers INTERFACE ${Boost_INCLUDE_DIRS})
  endif()
  # Legacy targets w/o functionality as all handled by defined targets
  foreach(lib diagnostic_definitions disable_autolinking dynamic_linking)
    if(NOT TARGET Boost::${lib})
      add_library(Boost::${lib} INTERFACE IMPORTED)
    endif()
  endforeach()
  if(NOT TARGET Boost::boost)
    add_library(Boost::boost INTERFACE IMPORTED)
    target_link_libraries(Boost::boost INTERFACE Boost::headers)
  endif()
endfunction()

#-------------------------------------------------------------------------------
# Before we go searching, check whether a boost cmake package is available, unless
# the user specifically asked NOT to search for one.
#
# 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)
  if (DEFINED Boost_DIR)
    mark_as_advanced(Boost_DIR)
  endif ()

  # If we found a boost cmake package, then we're done. Print out what we found.
  # Otherwise let the rest of the module try to find it.
  if(Boost_FOUND)
    # Convert component found variables to standard variables if required
    # Necessary for legacy boost-cmake and 1.70 builtin BoostConfig
    if(Boost_FIND_COMPONENTS)
      # Ignore the meta-component "ALL", introduced by Boost 1.73
      list(REMOVE_ITEM Boost_FIND_COMPONENTS "ALL")

      foreach(_comp IN LISTS Boost_FIND_COMPONENTS)
        if(DEFINED Boost_${_comp}_FOUND)
          continue()
        endif()
        string(TOUPPER ${_comp} _uppercomp)
        if(DEFINED Boost${_comp}_FOUND) # legacy boost-cmake project
          set(Boost_${_comp}_FOUND ${Boost${_comp}_FOUND})
        elseif(DEFINED Boost_${_uppercomp}_FOUND) # Boost 1.70
          set(Boost_${_comp}_FOUND ${Boost_${_uppercomp}_FOUND})
        endif()
      endforeach()
    endif()

    find_package_handle_standard_args(Boost HANDLE_COMPONENTS CONFIG_MODE)
    _boost_set_legacy_variables_from_config()

    # Restore project's policies
    cmake_policy(POP)
    return()
  endif()
endif()


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

#
# Print debug text if Boost_DEBUG is set.
# Call example:
# _Boost_DEBUG_PRINT("${CMAKE_CURRENT_LIST_FILE}" "${CMAKE_CURRENT_LIST_LINE}" "debug message")
#
function(_Boost_DEBUG_PRINT file line text)
  if(Boost_DEBUG)
    message(STATUS "[ ${file}:${line} ] ${text}")
  endif()
endfunction()

#
# _Boost_DEBUG_PRINT_VAR(file line variable_name [ENVIRONMENT]
#                        [SOURCE "short explanation of origin of var value"])
#
#   ENVIRONMENT - look up environment variable instead of CMake variable
#
# Print variable name and its value if Boost_DEBUG is set.
# Call example:
# _Boost_DEBUG_PRINT_VAR("${CMAKE_CURRENT_LIST_FILE}" "${CMAKE_CURRENT_LIST_LINE}" BOOST_ROOT)
#
function(_Boost_DEBUG_PRINT_VAR file line name)
  if(Boost_DEBUG)
    cmake_parse_arguments(_args "ENVIRONMENT" "SOURCE" "" ${ARGN})

    unset(source)
    if(_args_SOURCE)
      set(source " (${_args_SOURCE})")
    endif()

    if(_args_ENVIRONMENT)
      if(DEFINED ENV{${name}})
        set(value "\"$ENV{${name}}\"")
      else()
        set(value "<unset>")
      endif()
      set(_name "ENV{${name}}")
    else()
      if(DEFINED "${name}")
        set(value "\"${${name}}\"")
      else()
        set(value "<unset>")
      endif()
      set(_name "${name}")
    endif()

    _Boost_DEBUG_PRINT("${file}" "${line}" "${_name} = ${value}${source}")
  endif()
endfunction()

############################################
#
# 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)
    _Boost_DEBUG_PRINT_VAR("${CMAKE_CURRENT_LIST_FILE}" "${CMAKE_CURRENT_LIST_LINE}"
                           "Boost_LIBRARY_DIR_${build_type}")
    _Boost_DEBUG_PRINT_VAR("${CMAKE_CURRENT_LIST_FILE}" "${CMAKE_CURRENT_LIST_LINE}"
                           "_boost_LIBRARY_SEARCH_DIRS_${build_type}")
  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" OR "x${CMAKE_CXX_SIMULATE_ID}" STREQUAL "xMSVC")
    if(MSVC_TOOLSET_VERSION GREATER_EQUAL 150)
      # Not yet known.
      set(_boost_COMPILER "")
    elseif(MSVC_TOOLSET_VERSION GREATER_EQUAL 140)
      # MSVC toolset 14.x versions are forward compatible.
      set(_boost_COMPILER "")
      foreach(v 9 8 7 6 5 4 3 2 1 0)
        if(MSVC_TOOLSET_VERSION GREATER_EQUAL 14${v})
          list(APPEND _boost_COMPILER "-vc14${v}")
        endif()
      endforeach()
    elseif(MSVC_TOOLSET_VERSION GREATER_EQUAL 80)
      set(_boost_COMPILER "-vc${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()

    if("x${CMAKE_CXX_COMPILER_ID}" STREQUAL "xClang")
      string(REPLACE "." ";" VERSION_LIST "${CMAKE_CXX_COMPILER_VERSION}")
      list(GET VERSION_LIST 0 CLANG_VERSION_MAJOR)
      set(_boost_COMPILER "-clangw${CLANG_VERSION_MAJOR};${_boost_COMPILER}")
    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_VERSION_STRING 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${_boost_COMPILER_VERSION}")
    endif()
  elseif (UNIX)
    _Boost_COMPILER_DUMPVERSION(_boost_COMPILER_VERSION _boost_COMPILER_VERSION_MAJOR _boost_COMPILER_VERSION_MINOR)
    if(NOT Boost_VERSION_STRING VERSION_LESS 1.69.0)
      # From GCC 5 and clang 4, versioning changes and minor becomes patch.
      # For those compilers, patch is exclude from compiler tag in Boost 1.69+ library naming.
      if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU" AND _boost_COMPILER_VERSION_MAJOR VERSION_GREATER 4)
        set(_boost_COMPILER_VERSION "${_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_VERSION_STRING 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_VERSION_STRING VERSION_LESS 1.36.0)
            # In Boost <= 1.35.0, there is no mangled compiler name for
            # the macOS/Darwin version of GCC.
            set(_boost_COMPILER "")
          else()
            # In Boost 1.36.0 and newer, the mangled compiler name used
            # on macOS/Darwin is "xgcc".
            set(_boost_COMPILER "-xgcc${_boost_COMPILER_VERSION}")
          endif()
        else()
          set(_boost_COMPILER "-gcc${_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${_boost_COMPILER_VERSION}")
    endif()
  else()
    set(_boost_COMPILER "")
  endif()
  _Boost_DEBUG_PRINT_VAR("${CMAKE_CURRENT_LIST_FILE}" "${CMAKE_CURRENT_LIST_LINE}"
                         "_boost_COMPILER" SOURCE "guessed")
  set(${_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_STRING VERSION_LESS \1\.\2\.\3 AND Boost_VERSION_STRING 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. 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_STRING)
    if(Boost_VERSION_STRING VERSION_LESS 1.33.0)
      message(WARNING "Imported targets and dependency information not available for Boost version ${Boost_VERSION_STRING} (all versions older than 1.33)")
      set(_Boost_IMPORTED_TARGETS FALSE)
    elseif(Boost_VERSION_STRING VERSION_LESS 1.35.0)
      set(_Boost_IOSTREAMS_DEPENDENCIES regex thread)
      set(_Boost_REGEX_DEPENDENCIES thread)
      set(_Boost_WAVE_DEPENDENCIES filesystem thread)
      set(_Boost_WSERIALIZATION_DEPENDENCIES serialization)
    elseif(Boost_VERSION_STRING VERSION_LESS 1.36.0)
      set(_Boost_FILESYSTEM_DEPENDENCIES system)
      set(_Boost_IOSTREAMS_DEPENDENCIES regex)
      set(_Boost_MPI_DEPENDENCIES serialization)
      set(_Boost_MPI_PYTHON_DEPENDENCIES python${component_python_version} mpi serialization)
      set(_Boost_WAVE_DEPENDENCIES filesystem system thread)
      set(_Boost_WSERIALIZATION_DEPENDENCIES serialization)
    elseif(Boost_VERSION_STRING VERSION_LESS 1.38.0)
      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${component_python_version} mpi serialization)
      set(_Boost_WAVE_DEPENDENCIES filesystem system thread)
      set(_Boost_WSERIALIZATION_DEPENDENCIES serialization)
    elseif(Boost_VERSION_STRING VERSION_LESS 1.43.0)
      set(_Boost_FILESYSTEM_DEPENDENCIES system)
      set(_Boost_IOSTREAMS_DEPENDENCIES regex)
      set(_Boost_MATH_DEPENDENCIES math_c99 math_c99f math_c99l math_tr1 math_tr1f math_tr1l)
      set(_Boost_MPI_DEPENDENCIES serialization)
      set(_Boost_MPI_PYTHON_DEPENDENCIES python${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(Boost_VERSION_STRING VERSION_LESS 1.44.0)
      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${component_python_version} mpi serialization)
      set(_Boost_THREAD_DEPENDENCIES date_time)
      set(_Boost_WAVE_DEPENDENCIES filesystem system thread date_time)
      set(_Boost_WSERIALIZATION_DEPENDENCIES serialization)
    elseif(Boost_VERSION_STRING VERSION_LESS 1.45.0)
      set(_Boost_FILESYSTEM_DEPENDENCIES system)
      set(_Boost_IOSTREAMS_DEPENDENCIES regex)
      set(_Boost_MATH_DEPENDENCIES math_c99 math_c99f math_c99l math_tr1 math_tr1f math_tr1l random serialization)
      set(_Boost_MPI_DEPENDENCIES serialization)
      set(_Boost_MPI_PYTHON_DEPENDENCIES python${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(Boost_VERSION_STRING VERSION_LESS 1.47.0)
      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${component_python_version} mpi serialization)
      set(_Boost_THREAD_DEPENDENCIES date_time)
      set(_Boost_WAVE_DEPENDENCIES filesystem system serialization thread date_time)
      set(_Boost_WSERIALIZATION_DEPENDENCIES serialization)
    elseif(Boost_VERSION_STRING VERSION_LESS 1.48.0)
      set(_Boost_CHRONO_DEPENDENCIES system)
      set(_Boost_FILESYSTEM_DEPENDENCIES system)
      set(_Boost_IOSTREAMS_DEPENDENCIES regex)
      set(_Boost_MATH_DEPENDENCIES math_c99 math_c99f math_c99l math_tr1 math_tr1f math_tr1l random)
      set(_Boost_MPI_DEPENDENCIES serialization)
      set(_Boost_MPI_PYTHON_DEPENDENCIES python${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(Boost_VERSION_STRING VERSION_LESS 1.50.0)
      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${component_python_version} mpi serialization)
      set(_Boost_THREAD_DEPENDENCIES date_time)
      set(_Boost_TIMER_DEPENDENCIES chrono system)
      set(_Boost_WAVE_DEPENDENCIES filesystem system serialization thread date_time)
      set(_Boost_WSERIALIZATION_DEPENDENCIES serialization)
    elseif(Boost_VERSION_STRING VERSION_LESS 1.53.0)
      set(_Boost_CHRONO_DEPENDENCIES system)
      set(_Boost_FILESYSTEM_DEPENDENCIES system)
      set(_Boost_IOSTREAMS_DEPENDENCIES regex)
      set(_Boost_MATH_DEPENDENCIES math_c99 math_c99f math_c99l math_tr1 math_tr1f math_tr1l regex random)
      set(_Boost_MPI_DEPENDENCIES serialization)
      set(_Boost_MPI_PYTHON_DEPENDENCIES python${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(Boost_VERSION_STRING VERSION_LESS 1.54.0)
      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${component_python_version} mpi serialization)
      set(_Boost_THREAD_DEPENDENCIES chrono system date_time atomic)
      set(_Boost_TIMER_DEPENDENCIES chrono system)
      set(_Boost_WAVE_DEPENDENCIES filesystem system serialization thread chrono date_time)
      set(_Boost_WSERIALIZATION_DEPENDENCIES serialization)
    elseif(Boost_VERSION_STRING VERSION_LESS 1.55.0)
      set(_Boost_ATOMIC_DEPENDENCIES thread chrono system date_time)
      set(_Boost_CHRONO_DEPENDENCIES system)
      set(_Boost_FILESYSTEM_DEPENDENCIES system)
      set(_Boost_IOSTREAMS_DEPENDENCIES regex)
      set(_Boost_LOG_DEPENDENCIES log_setup date_time system filesystem thread regex chrono)
      set(_Boost_MATH_DEPENDENCIES math_c99 math_c99f math_c99l math_tr1 math_tr1f math_tr1l regex random)
      set(_Boost_MPI_DEPENDENCIES serialization)
      set(_Boost_MPI_PYTHON_DEPENDENCIES python${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(Boost_VERSION_STRING VERSION_LESS 1.56.0)
      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${component_python_version} mpi serialization)
      set(_Boost_THREAD_DEPENDENCIES chrono system date_time atomic)
      set(_Boost_TIMER_DEPENDENCIES chrono system)
      set(_Boost_WAVE_DEPENDENCIES filesystem system serialization thread chrono date_time atomic)
      set(_Boost_WSERIALIZATION_DEPENDENCIES serialization)
    elseif(Boost_VERSION_STRING VERSION_LESS 1.59.0)
      set(_Boost_CHRONO_DEPENDENCIES system)
      set(_Boost_COROUTINE_DEPENDENCIES context system)
      set(_Boost_FILESYSTEM_DEPENDENCIES system)
      set(_Boost_IOSTREAMS_DEPENDENCIES regex)
      set(_Boost_LOG_DEPENDENCIES log_setup date_time system filesystem thread regex chrono)
      set(_Boost_MATH_DEPENDENCIES math_c99 math_c99f math_c99l math_tr1 math_tr1f math_tr1l atomic)
      set(_Boost_MPI_DEPENDENCIES serialization)
      set(_Boost_MPI_PYTHON_DEPENDENCIES python${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(Boost_VERSION_STRING VERSION_LESS 1.60.0)
      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${component_python_version} mpi serialization)
      set(_Boost_RANDOM_DEPENDENCIES system)
      set(_Boost_THREAD_DEPENDENCIES chrono system date_time atomic)
      set(_Boost_TIMER_DEPENDENCIES chrono system)
      set(_Boost_WAVE_DEPENDENCIES filesystem system serialization thread chrono date_time atomic)
      set(_Boost_WSERIALIZATION_DEPENDENCIES serialization)
    elseif(Boost_VERSION_STRING VERSION_LESS 1.61.0)
      set(_Boost_CHRONO_DEPENDENCIES system)
      set(_Boost_COROUTINE_DEPENDENCIES context system)
      set(_Boost_FILESYSTEM_DEPENDENCIES system)
      set(_Boost_IOSTREAMS_DEPENDENCIES regex)
      set(_Boost_LOG_DEPENDENCIES date_time log_setup system filesystem thread regex chrono atomic)
      set(_Boost_MATH_DEPENDENCIES math_c99 math_c99f math_c99l math_tr1 math_tr1f math_tr1l atomic)
      set(_Boost_MPI_DEPENDENCIES serialization)
      set(_Boost_MPI_PYTHON_DEPENDENCIES python${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(Boost_VERSION_STRING VERSION_LESS 1.62.0)
      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${component_python_version} mpi serialization)
      set(_Boost_RANDOM_DEPENDENCIES system)
      set(_Boost_THREAD_DEPENDENCIES chrono system date_time atomic)
      set(_Boost_WAVE_DEPENDENCIES filesystem system serialization thread chrono date_time atomic)
      set(_Boost_WSERIALIZATION_DEPENDENCIES serialization)
    elseif(Boost_VERSION_STRING VERSION_LESS 1.63.0)
      set(_Boost_CHRONO_DEPENDENCIES system)
      set(_Boost_CONTEXT_DEPENDENCIES thread chrono system date_time)
      set(_Boost_COROUTINE_DEPENDENCIES context system)
      set(_Boost_FIBER_DEPENDENCIES context thread chrono system date_time)
      set(_Boost_FILESYSTEM_DEPENDENCIES system)
      set(_Boost_IOSTREAMS_DEPENDENCIES regex)
      set(_Boost_LOG_DEPENDENCIES date_time log_setup system filesystem thread regex chrono atomic)
      set(_Boost_MATH_DEPENDENCIES math_c99 math_c99f math_c99l math_tr1 math_tr1f math_tr1l atomic)
      set(_Boost_MPI_DEPENDENCIES serialization)
      set(_Boost_MPI_PYTHON_DEPENDENCIES python${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(Boost_VERSION_STRING VERSION_LESS 1.65.0)
      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${component_python_version} mpi serialization)
      set(_Boost_RANDOM_DEPENDENCIES system)
      set(_Boost_THREAD_DEPENDENCIES chrono system date_time atomic)
      set(_Boost_WAVE_DEPENDENCIES filesystem system serialization thread chrono date_time atomic)
      set(_Boost_WSERIALIZATION_DEPENDENCIES serialization)
    elseif(Boost_VERSION_STRING VERSION_LESS 1.67.0)
      set(_Boost_CHRONO_DEPENDENCIES system)
      set(_Boost_CONTEXT_DEPENDENCIES thread chrono system date_time)
      set(_Boost_COROUTINE_DEPENDENCIES context system)
      set(_Boost_FIBER_DEPENDENCIES context thread chrono system date_time)
      set(_Boost_FILESYSTEM_DEPENDENCIES system)
      set(_Boost_IOSTREAMS_DEPENDENCIES regex)
      set(_Boost_LOG_DEPENDENCIES date_time log_setup system filesystem thread regex chrono atomic)
      set(_Boost_MATH_DEPENDENCIES math_c99 math_c99f math_c99l math_tr1 math_tr1f math_tr1l atomic)
      set(_Boost_MPI_DEPENDENCIES serialization)
      set(_Boost_MPI_PYTHON_DEPENDENCIES python${component_python_version} mpi serialization)
      set(_Boost_NUMPY_DEPENDENCIES python${component_python_version})
      set(_Boost_RANDOM_DEPENDENCIES system)
      set(_Boost_THREAD_DEPENDENCIES chrono system date_time atomic)
      set(_Boost_TIMER_DEPENDENCIES chrono system)
      set(_Boost_WAVE_DEPENDENCIES filesystem system serialization thread chrono date_time atomic)
      set(_Boost_WSERIALIZATION_DEPENDENCIES serialization)
    elseif(Boost_VERSION_STRING VERSION_LESS 1.68.0)
      set(_Boost_CHRONO_DEPENDENCIES system)
      set(_Boost_CONTEXT_DEPENDENCIES thread chrono system date_time)
      set(_Boost_COROUTINE_DEPENDENCIES context system)
      set(_Boost_FIBER_DEPENDENCIES context thread chrono system date_time)
      set(_Boost_FILESYSTEM_DEPENDENCIES system)
      set(_Boost_IOSTREAMS_DEPENDENCIES regex)
      set(_Boost_LOG_DEPENDENCIES date_time log_setup system filesystem thread regex chrono atomic)
      set(_Boost_MATH_DEPENDENCIES math_c99 math_c99f math_c99l math_tr1 math_tr1f math_tr1l atomic)
      set(_Boost_MPI_DEPENDENCIES serialization)
      set(_Boost_MPI_PYTHON_DEPENDENCIES python${component_python_version} mpi serialization)
      set(_Boost_NUMPY_DEPENDENCIES python${component_python_version})
      set(_Boost_RANDOM_DEPENDENCIES system)
      set(_Boost_THREAD_DEPENDENCIES chrono system date_time atomic)
      set(_Boost_TIMER_DEPENDENCIES chrono system)
      set(_Boost_WAVE_DEPENDENCIES filesystem system serialization thread chrono date_time atomic)
      set(_Boost_WSERIALIZATION_DEPENDENCIES serialization)
    elseif(Boost_VERSION_STRING VERSION_LESS 1.69.0)
      set(_Boost_CHRONO_DEPENDENCIES system)
      set(_Boost_CONTEXT_DEPENDENCIES thread chrono system date_time)
      set(_Boost_CONTRACT_DEPENDENCIES thread chrono system date_time)
      set(_Boost_COROUTINE_DEPENDENCIES context system)
      set(_Boost_FIBER_DEPENDENCIES context thread chrono system date_time)
      set(_Boost_FILESYSTEM_DEPENDENCIES system)
      set(_Boost_IOSTREAMS_DEPENDENCIES regex)
      set(_Boost_LOG_DEPENDENCIES date_time log_setup system filesystem thread regex chrono atomic)
      set(_Boost_MATH_DEPENDENCIES math_c99 math_c99f math_c99l math_tr1 math_tr1f math_tr1l atomic)
      set(_Boost_MPI_DEPENDENCIES serialization)
      set(_Boost_MPI_PYTHON_DEPENDENCIES python${component_python_version} mpi serialization)
      set(_Boost_NUMPY_DEPENDENCIES python${component_python_version})
      set(_Boost_RANDOM_DEPENDENCIES system)
      set(_Boost_THREAD_DEPENDENCIES chrono system date_time atomic)
      set(_Boost_TIMER_DEPENDENCIES chrono system)
      set(_Boost_WAVE_DEPENDENCIES filesystem system serialization thread chrono date_time atomic)
      set(_Boost_WSERIALIZATION_DEPENDENCIES serialization)
    elseif(Boost_VERSION_STRING VERSION_LESS 1.70.0)
      set(_Boost_CONTRACT_DEPENDENCIES thread chrono date_time)
      set(_Boost_COROUTINE_DEPENDENCIES context)
      set(_Boost_FIBER_DEPENDENCIES context)
      set(_Boost_IOSTREAMS_DEPENDENCIES regex)
      set(_Boost_LOG_DEPENDENCIES date_time log_setup filesystem thread regex chrono atomic)
      set(_Boost_MATH_DEPENDENCIES math_c99 math_c99f math_c99l math_tr1 math_tr1f math_tr1l atomic)
      set(_Boost_MPI_DEPENDENCIES serialization)
      set(_Boost_MPI_PYTHON_DEPENDENCIES python${component_python_version} mpi serialization)
      set(_Boost_NUMPY_DEPENDENCIES python${component_python_version})
      set(_Boost_THREAD_DEPENDENCIES chrono date_time atomic)
      set(_Boost_TIMER_DEPENDENCIES chrono system)
      set(_Boost_WAVE_DEPENDENCIES filesystem serialization thread chrono date_time atomic)
      set(_Boost_WSERIALIZATION_DEPENDENCIES serialization)
    elseif(Boost_VERSION_STRING VERSION_LESS 1.72.0)
      set(_Boost_CONTRACT_DEPENDENCIES thread chrono date_time)
      set(_Boost_COROUTINE_DEPENDENCIES context)
      set(_Boost_FIBER_DEPENDENCIES context)
      set(_Boost_IOSTREAMS_DEPENDENCIES regex)
      set(_Boost_LOG_DEPENDENCIES date_time log_setup filesystem thread regex chrono atomic)
      set(_Boost_MATH_DEPENDENCIES math_c99 math_c99f math_c99l math_tr1 math_tr1f math_tr1l atomic)
      set(_Boost_MPI_DEPENDENCIES serialization)
      set(_Boost_MPI_PYTHON_DEPENDENCIES python${component_python_version} mpi serialization)
      set(_Boost_NUMPY_DEPENDENCIES python${component_python_version})
      set(_Boost_THREAD_DEPENDENCIES chrono date_time atomic)
      set(_Boost_TIMER_DEPENDENCIES chrono)
      set(_Boost_WAVE_DEPENDENCIES filesystem serialization thread chrono date_time atomic)
      set(_Boost_WSERIALIZATION_DEPENDENCIES serialization)
    elseif(Boost_VERSION_STRING VERSION_LESS 1.73.0)
      set(_Boost_CONTRACT_DEPENDENCIES thread chrono date_time)
      set(_Boost_COROUTINE_DEPENDENCIES context)
      set(_Boost_FIBER_DEPENDENCIES context)
      set(_Boost_IOSTREAMS_DEPENDENCIES regex)
      set(_Boost_LOG_DEPENDENCIES date_time log_setup filesystem thread regex chrono atomic)
      set(_Boost_MATH_DEPENDENCIES math_c99 math_c99f math_c99l math_tr1 math_tr1f math_tr1l chrono atomic)
      set(_Boost_MPI_DEPENDENCIES serialization)
      set(_Boost_MPI_PYTHON_DEPENDENCIES python${component_python_version} mpi serialization)
      set(_Boost_NUMPY_DEPENDENCIES python${component_python_version})
      set(_Boost_THREAD_DEPENDENCIES chrono date_time atomic)
      set(_Boost_TIMER_DEPENDENCIES chrono)
      set(_Boost_WAVE_DEPENDENCIES filesystem serialization thread chrono date_time atomic)
      set(_Boost_WSERIALIZATION_DEPENDENCIES serialization)
    else()
      set(_Boost_CONTRACT_DEPENDENCIES thread chrono date_time)
      set(_Boost_COROUTINE_DEPENDENCIES context)
      set(_Boost_FIBER_DEPENDENCIES context)
      set(_Boost_IOSTREAMS_DEPENDENCIES regex)
      set(_Boost_LOG_DEPENDENCIES date_time log_setup filesystem thread regex chrono atomic)
      set(_Boost_MATH_DEPENDENCIES math_c99 math_c99f math_c99l math_tr1 math_tr1f math_tr1l atomic)
      set(_Boost_MPI_DEPENDENCIES serialization)
      set(_Boost_MPI_PYTHON_DEPENDENCIES python${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)
      set(_Boost_WAVE_DEPENDENCIES filesystem serialization thread chrono date_time atomic)
      set(_Boost_WSERIALIZATION_DEPENDENCIES serialization)
      if(NOT Boost_VERSION_STRING VERSION_LESS 1.73.0)
        message(WARNING "New Boost version may have incorrect or missing dependencies and imported targets")
      endif()
    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_STRING VERSION_LESS 1.61.0)
    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_NOWIDE_HEADERS              "boost/nowide/cstdlib.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
# - `${Boost_ROOT}/libs/fiber/build/Jamfile.v2`;
# - `${Boost_ROOT}/libs/context/build/Jamfile.v2`.
#
# TODO (Re)Check compiler features on (every?) release ???
# One may use the following command to get the files to check:
#
#   $ find . -name Jamfile.v2 | grep build | xargs grep -l cxx1
#
function(_Boost_COMPILER_FEATURES component _ret)
  # Boost >= 1.62
  if(NOT Boost_VERSION_STRING VERSION_LESS 1.62.0)
    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
    )
    # Compiler feature for `context` same as for `fiber`.
    set(_Boost_CONTEXT_COMPILER_FEATURES ${_Boost_FIBER_COMPILER_FEATURES})
  endif()

  # Boost Contract library available in >= 1.67
  if(NOT Boost_VERSION_STRING VERSION_LESS 1.67.0)
    # From `libs/contract/build/boost_contract_build.jam`
    set(_Boost_CONTRACT_COMPILER_FEATURES
        cxx_lambdas
        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${CMAKE_CXX_COMPILER_ID}" STREQUAL "xMSVC")
    if(CMAKE_SIZEOF_VOID_P EQUAL 8)
      set(_arch_suffix 64)
    else()
      set(_arch_suffix 32)
    endif()
    if(MSVC_TOOLSET_VERSION GREATER_EQUAL 150)
      # Not yet known.
    elseif(MSVC_TOOLSET_VERSION GREATER_EQUAL 140)
      # MSVC toolset 14.x versions are forward compatible.
      foreach(v 9 8 7 6 5 4 3 2 1 0)
        if(MSVC_TOOLSET_VERSION GREATER_EQUAL 14${v})
          list(APPEND ${componentlibvar} ${basedir}/lib${_arch_suffix}-msvc-14.${v})
        endif()
      endforeach()
    elseif(MSVC_TOOLSET_VERSION GREATER_EQUAL 80)
      math(EXPR _toolset_major_version "${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}
    "1.72.0" "1.72" "1.71.0" "1.71" "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()

_Boost_DEBUG_PRINT_VAR("${CMAKE_CURRENT_LIST_FILE}" "${CMAKE_CURRENT_LIST_LINE}" "_boost_TEST_VERSIONS")
_Boost_DEBUG_PRINT_VAR("${CMAKE_CURRENT_LIST_FILE}" "${CMAKE_CURRENT_LIST_LINE}" "Boost_USE_MULTITHREADED")
_Boost_DEBUG_PRINT_VAR("${CMAKE_CURRENT_LIST_FILE}" "${CMAKE_CURRENT_LIST_LINE}" "Boost_USE_STATIC_LIBS")
_Boost_DEBUG_PRINT_VAR("${CMAKE_CURRENT_LIST_FILE}" "${CMAKE_CURRENT_LIST_LINE}" "Boost_USE_STATIC_RUNTIME")
_Boost_DEBUG_PRINT_VAR("${CMAKE_CURRENT_LIST_FILE}" "${CMAKE_CURRENT_LIST_LINE}" "Boost_ADDITIONAL_VERSIONS")
_Boost_DEBUG_PRINT_VAR("${CMAKE_CURRENT_LIST_FILE}" "${CMAKE_CURRENT_LIST_LINE}" "Boost_NO_SYSTEM_PATHS")

cmake_policy(GET CMP0074 _Boost_CMP0074)
if(NOT "x${_Boost_CMP0074}x" STREQUAL "xNEWx")
  _Boost_CHECK_SPELLING(Boost_ROOT)
endif()
unset(_Boost_CMP0074)
_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
  )

_Boost_DEBUG_PRINT_VAR("${CMAKE_CURRENT_LIST_FILE}" "${CMAKE_CURRENT_LIST_LINE}" "BOOST_ROOT")
_Boost_DEBUG_PRINT_VAR("${CMAKE_CURRENT_LIST_FILE}" "${CMAKE_CURRENT_LIST_LINE}" "BOOST_ROOT" ENVIRONMENT)
_Boost_DEBUG_PRINT_VAR("${CMAKE_CURRENT_LIST_FILE}" "${CMAKE_CURRENT_LIST_LINE}" "BOOST_INCLUDEDIR")
_Boost_DEBUG_PRINT_VAR("${CMAKE_CURRENT_LIST_FILE}" "${CMAKE_CURRENT_LIST_LINE}" "BOOST_INCLUDEDIR" ENVIRONMENT)
_Boost_DEBUG_PRINT_VAR("${CMAKE_CURRENT_LIST_FILE}" "${CMAKE_CURRENT_LIST_LINE}" "BOOST_LIBRARYDIR")
_Boost_DEBUG_PRINT_VAR("${CMAKE_CURRENT_LIST_FILE}" "${CMAKE_CURRENT_LIST_LINE}" "BOOST_LIBRARYDIR" ENVIRONMENT)

# ------------------------------------------------------------------------
#  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.