ENH: Cleanup FindBoost module, fixing several small bugs and providing better diagnostic information when things go wrong

Modules/FindBoost.cmake

@@ -41,7 +41,7 @@
 #                                version set this variable to a list of
 #                                strings, where each string contains a number, i.e.
 #                                SET(Boost_ADDITIONAL_VERSIONS "0.99.0" "1.35.0")
-#  BOOST_ROOT                    Preferred installation prefix for searching for Boost,
+#  BOOST_ROOT or BOOSTROOT       Preferred installation prefix for searching for Boost,
 #                                set this if the module has problems finding the proper Boost installation
 #  BOOST_INCLUDEDIR              Set this to the include directory of Boost, if the
 #                                module has problems finding the proper Boost installation
@@ -91,20 +91,28 @@
 #  BSD license.
 #  For details see the accompanying COPYING-CMAKE-SCRIPTS file.
 #
-
-# this module required CMake 2.5 for the Boost_FIND_VERSION stuff
-
-# this must not be done in find modules, it changes the policy settings, which may have been
-# set in the projects cmake files.
-# beside that this module comes with cmake, so the cmake version is always correct, Alex
-# CMAKE_MINIMUM_REQUIRED(VERSION "2.6" FATAL_ERROR)
-
-# MESSAGE(STATUS "Finding Boost libraries.... ")
-
-OPTION(Boost_USE_MULTITHREADED "Use the multithreaded versions of the boost libraries" ON)
-
-SET( _boost_TEST_VERSIONS ${Boost_ADDITIONAL_VERSIONS} "1.36.1" "1.36.0" "1.35.1" "1.35.0" "1.35" "1.34.1" "1.34.0" "1.34" "1.33.1" "1.33.0" "1.33" )
-
+OPTION(Boost_USE_MULTITHREADED 
+  "Use the multithreaded versions of the Boost libraries" ON)
+
+if (Boost_FIND_VERSION_EXACT)
+  if (Boost_FIND_VERSION_PATCH)
+    set( _boost_TEST_VERSIONS 
+      "${Boost_FIND_VERSION_MAJOR}.${Boost_FIND_VERSION_MINOR}.${Boost_FIND_VERSION_PATCH}")
+  else (Boost_FIND_VERSION_PATCH)
+    set( _boost_TEST_VERSIONS 
+      "${Boost_FIND_VERSION_MAJOR}.${Boost_FIND_VERSION_MINOR}.0"
+      "${Boost_FIND_VERSION_MAJOR}.${Boost_FIND_VERSION_MINOR}")
+  endif (Boost_FIND_VERSION_PATCH)
+else (Boost_FIND_VERSION_EXACT)
+  set( _boost_TEST_VERSIONS ${Boost_ADDITIONAL_VERSIONS} 
+    "1.36.1" "1.36.0" "1.35.1" "1.35.0" "1.35" "1.34.1" "1.34.0" "1.34" "1.33.1"
+    "1.33.0" "1.33" )
+endif (Boost_FIND_VERSION_EXACT)
+
+# 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)
 
 ############################################
 #
@@ -119,8 +127,6 @@ SET( _boost_TEST_VERSIONS ${Boost_ADDITIONAL_VERSIONS} "1.36.1" "1.36.0" "1.35.1
 
 MACRO (_Boost_ADJUST_LIB_VARS basename)
   IF (Boost_INCLUDE_DIR )
-    #MESSAGE(STATUS "Adjusting ${basename} ")
-
     IF (Boost_${basename}_LIBRARY_DEBUG AND Boost_${basename}_LIBRARY_RELEASE)
       # if the generator supports configuration types then set
       # optimized and debug libraries, or if the CMAKE_BUILD_TYPE has a value
@@ -152,7 +158,7 @@ MACRO (_Boost_ADJUST_LIB_VARS basename)
       SET(Boost_${basename}_LIBRARY ${Boost_${basename}_LIBRARY} CACHE FILEPATH "The Boost ${basename} library")
       GET_FILENAME_COMPONENT(Boost_LIBRARY_DIRS "${Boost_${basename}_LIBRARY}" PATH)
       SET(Boost_LIBRARY_DIRS ${Boost_LIBRARY_DIRS} CACHE FILEPATH "Boost library directory")
-      SET(Boost_${basename}_FOUND ON CACHE INTERNAL "Was the boost boost ${basename} library found")
+      SET(Boost_${basename}_FOUND ON CACHE INTERNAL "Whether the Boost ${basename} library found")
     ENDIF (Boost_${basename}_LIBRARY)
 
   ENDIF (Boost_INCLUDE_DIR )
@@ -197,120 +203,113 @@ ELSE (_boost_IN_CACHE)
   # Need to search for boost
 
   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.
+    # 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.
+    # 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" CACHE STRING "Boost diagnostic define")
+    # 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" CACHE STRING "Boost diagnostic define")
   ENDIF(WIN32)
 
-
   SET(_boost_INCLUDE_SEARCH_DIRS
     C:/boost/include
-    "C:/Program Files/boost/boost_${Boost_FIND_VERSION_MAJOR}_${Boost_FIND_VERSION_MINOR}_${Boost_FIND_VERSION_PATCH}"
-    # D: is very often the cdrom drive, IF you don't have a
-    # cdrom inserted it will popup a very annoying dialog
-    #D:/boost/include
+    "${ENV}{ProgramFiles}/boost/boost_${Boost_FIND_VERSION_MAJOR}_${Boost_FIND_VERSION_MINOR}_${Boost_FIND_VERSION_PATCH}"
     /sw/local/include
   )
 
   SET(_boost_LIBRARIES_SEARCH_DIRS
     C:/boost/lib
-    "C:/Program Files/boost/boost_${Boost_FIND_VERSION_MAJOR}_${Boost_FIND_VERSION_MINOR}_${Boost_FIND_VERSION_PATCH}/lib"
+    "${ENV}{ProgramFiles}/boost/boost_${Boost_FIND_VERSION_MAJOR}_${Boost_FIND_VERSION_MINOR}_${Boost_FIND_VERSION_PATCH}/lib"
     /sw/local/lib
   )
 
-  IF( NOT $ENV{BOOST_ROOT} STREQUAL "" )
-    SET(_boost_INCLUDE_SEARCH_DIRS $ENV{BOOST_ROOT}/include ${_boost_INCLUDE_SEARCH_DIRS})
-    SET(_boost_LIBRARIES_SEARCH_DIRS $ENV{BOOST_ROOT}/lib ${_boost_INCLUDE_SEARCH_DIRS})
-  ENDIF( NOT $ENV{BOOST_ROOT} STREQUAL "" )
+  # If BOOST_ROOT was defined in the environment, use it.
+  if (NOT BOOST_ROOT AND NOT $ENV{BOOST_ROOT} STREQUAL "")
+    set(BOOST_ROOT $ENV{BOOST_ROOT})
+  endif(NOT BOOST_ROOT AND NOT $ENV{BOOST_ROOT} STREQUAL "")
+
+  # If BOOSTROOT was defined in the environment, use it.
+  if (NOT BOOST_ROOT AND NOT $ENV{BOOSTROOT} STREQUAL "")
+    set(BOOST_ROOT $ENV{BOOSTROOT})
+  endif(NOT BOOST_ROOT AND NOT $ENV{BOOSTROOT} STREQUAL "")
 
+  # If BOOST_INCLUDEDIR was defined in the environment, use it.
   IF( NOT $ENV{BOOST_INCLUDEDIR} STREQUAL "" )
-    SET(_boost_INCLUDE_SEARCH_DIRS $ENV{BOOST_INCLUDEDIR} ${_boost_INCLUDE_SEARCH_DIRS})
+    set(BOOST_INCLUDEDIR $ENV{BOOST_INCLUDEDIR})
   ENDIF( NOT $ENV{BOOST_INCLUDEDIR} STREQUAL "" )
 
+  # If BOOST_LIBRARYDIR was defined in the environment, use it.
   IF( NOT $ENV{BOOST_LIBRARYDIR} STREQUAL "" )
-    SET(_boost_LIBRARIES_SEARCH_DIRS $ENV{BOOST_LIBRARYDIR} ${_boost_INCLUDE_SEARCH_DIRS})
+    set(BOOST_LIBRARYDIR $ENV{BOOST_LIBRARYDIR})
   ENDIF( NOT $ENV{BOOST_LIBRARYDIR} STREQUAL "" )
 
   IF( BOOST_ROOT )
-    IF( WIN32 )
-      SET(_boost_INCLUDE_SEARCH_DIRS ${BOOST_ROOT} ${_boost_INCLUDE_SEARCH_DIRS})
-    ELSE( WIN32 )
-      SET(_boost_INCLUDE_SEARCH_DIRS ${BOOST_ROOT}/include ${_boost_INCLUDE_SEARCH_DIRS})
-    ENDIF( WIN32 )
-    SET(_boost_LIBRARIES_SEARCH_DIRS ${BOOST_ROOT}/lib ${_boost_LIBRARIES_SEARCH_DIRS})
+    file(TO_CMAKE_PATH ${BOOST_ROOT} BOOST_ROOT)
+    SET(_boost_INCLUDE_SEARCH_DIRS 
+      ${BOOST_ROOT}/include 
+      ${BOOST_ROOT}
+      ${_boost_INCLUDE_SEARCH_DIRS})
+    SET(_boost_LIBRARIES_SEARCH_DIRS 
+      ${BOOST_ROOT}/lib 
+      ${BOOST_ROOT}/stage/lib 
+      ${_boost_LIBRARIES_SEARCH_DIRS})
   ENDIF( BOOST_ROOT )
 
   IF( BOOST_INCLUDEDIR )
-    SET(_boost_INCLUDE_SEARCH_DIRS ${BOOST_INCLUDEDIR} ${_boost_INCLUDE_SEARCH_DIRS})
+    file(TO_CMAKE_PATH ${BOOST_INCLUDEDIR} BOOST_INCLUDEDIR)
+    SET(_boost_INCLUDE_SEARCH_DIRS 
+      ${BOOST_INCLUDEDIR} ${_boost_INCLUDE_SEARCH_DIRS})
   ENDIF( BOOST_INCLUDEDIR )
 
   IF( BOOST_LIBRARYDIR )
-    SET(_boost_LIBRARIES_SEARCH_DIRS ${BOOST_LIBRARYDIR} ${_boost_LIBRARIES_SEARCH_DIRS})
+    file(TO_CMAKE_PATH ${BOOST_LIBRARYDIR} BOOST_LIBRARYDIR)
+    SET(_boost_LIBRARIES_SEARCH_DIRS 
+      ${BOOST_LIBRARYDIR} ${_boost_LIBRARIES_SEARCH_DIRS})
   ENDIF( BOOST_LIBRARYDIR )
 
-  #Try first in our own include search paths (e.g. BOOST_ROOT)
+  # Try to find Boost by stepping backwards through the Boost versions
+  # we know about.
   FOREACH(_boost_VER ${_boost_TEST_VERSIONS})
     IF( NOT Boost_INCLUDE_DIR )
-
-      # Add in a path suffix, based on the required version, ideally we could
-      # read this from version.hpp, but for that to work we'd need to know the include
-      # dir already
-      SET(_boost_PATH_SUFFIX
-        boost-${_boost_VER}
-      )
+      # 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
+      if (WIN32 AND NOT CYGWIN)
+        set(_boost_PATH_SUFFIX boost_${_boost_VER})
+      else (WIN32 AND NOT CYGWIN)
+        set(_boost_PATH_SUFFIX boost-${_boost_VER})
+      endif (WIN32 AND NOT CYGWIN)
 
       IF(_boost_PATH_SUFFIX MATCHES "[0-9]+\\.[0-9]+\\.[0-9]+")
-          STRING(REGEX REPLACE "([0-9]+)\\.([0-9]+)\\.([0-9]+)" "\\1_\\2_\\3" _boost_PATH_SUFFIX ${_boost_PATH_SUFFIX})
+          STRING(REGEX REPLACE "([0-9]+)\\.([0-9]+)\\.([0-9]+)" "\\1_\\2_\\3" 
+            _boost_PATH_SUFFIX ${_boost_PATH_SUFFIX})
       ELSEIF(_boost_PATH_SUFFIX MATCHES "[0-9]+\\.[0-9]+")
-          STRING(REGEX REPLACE "([0-9]+)\\.([0-9]+)" "\\1_\\2" _boost_PATH_SUFFIX ${_boost_PATH_SUFFIX})
+          STRING(REGEX REPLACE "([0-9]+)\\.([0-9]+)" "\\1_\\2" 
+            _boost_PATH_SUFFIX ${_boost_PATH_SUFFIX})
       ENDIF(_boost_PATH_SUFFIX MATCHES "[0-9]+\\.[0-9]+\\.[0-9]+")
 
-
       FIND_PATH(Boost_INCLUDE_DIR
           NAMES         boost/config.hpp
-          PATHS         ${_boost_INCLUDE_SEARCH_DIRS}
+          HINTS         ${_boost_INCLUDE_SEARCH_DIRS}
           PATH_SUFFIXES ${_boost_PATH_SUFFIX}
-          NO_DEFAULT_PATH
       )
 
     ENDIF( NOT Boost_INCLUDE_DIR )
   ENDFOREACH(_boost_VER)
 
-  # If nothing is found search again using system default paths
-  FOREACH(_boost_VER ${_boost_TEST_VERSIONS})
-    IF( NOT Boost_INCLUDE_DIR )
-
-      # Add in a path suffix, based on the required version, ideally we could
-      # read this from version.hpp, but for that to work we'd need to know the include
-      # dir already
-      SET(_boost_PATH_SUFFIX
-        boost-${_boost_VER}
-      )
-
-      IF(_boost_PATH_SUFFIX MATCHES "[0-9]+\\.[0-9]+\\.[0-9]+")
-          STRING(REGEX REPLACE "([0-9]+)\\.([0-9]+)\\.([0-9]+)" "\\1_\\2_\\3" _boost_PATH_SUFFIX ${_boost_PATH_SUFFIX})
-      ELSEIF(_boost_PATH_SUFFIX MATCHES "[0-9]+\\.[0-9]+")
-          STRING(REGEX REPLACE "([0-9]+)\\.([0-9]+)" "\\1_\\2" _boost_PATH_SUFFIX ${_boost_PATH_SUFFIX})
-      ENDIF(_boost_PATH_SUFFIX MATCHES "[0-9]+\\.[0-9]+\\.[0-9]+")
-
-      FIND_PATH(Boost_INCLUDE_DIR
-          NAMES         boost/config.hpp
-          PATH_SUFFIXES ${_boost_PATH_SUFFIX}
-      )
- 
-    ENDIF( NOT Boost_INCLUDE_DIR )
-  ENDFOREACH(_boost_VER)
   IF(Boost_INCLUDE_DIR)
     # Extract Boost_VERSION and Boost_LIB_VERSION from version.hpp
     # Read the whole file:
@@ -329,52 +328,53 @@ ELSE (_boost_IN_CACHE)
       MATH(EXPR Boost_MAJOR_VERSION "${Boost_VERSION} / 100000")
       MATH(EXPR Boost_MINOR_VERSION "${Boost_VERSION} / 100 % 1000")
       MATH(EXPR Boost_SUBMINOR_VERSION "${Boost_VERSION} % 100")
-  
+
+      set(Boost_ERROR_REASON
+          "${Boost_ERROR_REASON}Boost version: ${Boost_MAJOR_VERSION}.${Boost_MINOR_VERSION}.${Boost_SUBMINOR_VERSION}\nBoost include path: ${Boost_INCLUDE_DIR}")
     ENDIF(NOT "${Boost_VERSION}" STREQUAL "0")
+  ELSE(Boost_INCLUDE_DIR)
+    set(Boost_ERROR_REASON
+      "${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(Boost_INCLUDE_DIR)
 
-
-  #Setting some more suffixes for the library
+  # Setting some more suffixes for the library
   SET (Boost_LIB_PREFIX "")
   IF ( WIN32 AND Boost_USE_STATIC_LIBS )
     SET (Boost_LIB_PREFIX "lib")
   ENDIF ( WIN32 AND Boost_USE_STATIC_LIBS )
   SET (_boost_COMPILER "-gcc")
-  IF (MSVC71)
-    SET (_boost_COMPILER "-vc71")
-  ENDIF(MSVC71)
-  IF (MSVC80)
-    SET (_boost_COMPILER "-vc80")
-  ENDIF(MSVC80)
   IF (MSVC90)
     SET (_boost_COMPILER "-vc90")
-  ENDIF (MSVC90)
+  ELSEIF (MSVC80)
+    SET (_boost_COMPILER "-vc80")
+  ELSEIF (MSVC71)
+    SET (_boost_COMPILER "-vc71")
+  ENDIF(MSVC90)
   IF (MINGW)
     EXEC_PROGRAM(${CMAKE_CXX_COMPILER}
-      ARGS --version
+      ARGS -dumpversion
       OUTPUT_VARIABLE _boost_COMPILER_VERSION
       )
-    STRING(REGEX REPLACE ".* ([0-9])\\.([0-9])\\.[0-9] .*" "\\1\\2"
+    STRING(REGEX REPLACE "([0-9])\\.([0-9])\\.[0-9]" "\\1\\2"
       _boost_COMPILER_VERSION ${_boost_COMPILER_VERSION})
     SET (_boost_COMPILER "-mgw${_boost_COMPILER_VERSION}")
   ENDIF(MINGW)
-  IF (CYGWIN)
-    SET (_boost_COMPILER "-gcc")
-  ENDIF (CYGWIN)
   IF (UNIX)
     IF (APPLE)
-        SET (_boost_COMPILER "")
+      # Due to a quirk in Boost.Build, there is no compiler name
+      # mangled into library names on Mac OS X/Darwin.
+      SET (_boost_COMPILER "")
     ELSE (APPLE)
       IF (NOT CMAKE_COMPILER_IS_GNUCC)
-        # This is for the intel compiler
+        # We assume that we have the Intel compiler.
         SET (_boost_COMPILER "-il")
       ELSE (NOT CMAKE_COMPILER_IS_GNUCC)
-        #find out the version of gcc being used.
+        # Determine which version of GCC we have.
         EXEC_PROGRAM(${CMAKE_CXX_COMPILER}
-            ARGS --version
+            ARGS -dumpversion
             OUTPUT_VARIABLE _boost_COMPILER_VERSION
         )
-        STRING(REGEX REPLACE ".* ([0-9])\\.([0-9])\\.[0-9] .*" "\\1\\2"
+        STRING(REGEX REPLACE "([0-9])\\.([0-9])\\.[0-9]" "\\1\\2"
                _boost_COMPILER_VERSION ${_boost_COMPILER_VERSION})
         SET (_boost_COMPILER "-gcc${_boost_COMPILER_VERSION}")
       ENDIF (NOT CMAKE_COMPILER_IS_GNUCC)
@@ -423,39 +423,18 @@ ELSE (_boost_IN_CACHE)
                ${Boost_LIB_PREFIX}boost_${COMPONENT}${_boost_MULTITHREADED}
                ${Boost_LIB_PREFIX}boost_${COMPONENT}${_boost_MULTITHREADED}${_boost_STATIC_TAG}
                ${Boost_LIB_PREFIX}boost_${COMPONENT}
-        PATHS  ${_boost_LIBRARIES_SEARCH_DIRS}
-        NO_DEFAULT_PATH
+        HINTS  ${_boost_LIBRARIES_SEARCH_DIRS}
     )
 
-    IF( NOT ${Boost_${UPPERCOMPONENT}_LIBRARY_RELEASE} )
-      FIND_LIBRARY(Boost_${UPPERCOMPONENT}_LIBRARY_RELEASE
-          NAMES  ${Boost_LIB_PREFIX}boost_${COMPONENT}${_boost_COMPILER}${_boost_MULTITHREADED}-${Boost_LIB_VERSION}
-                 ${Boost_LIB_PREFIX}boost_${COMPONENT}${_boost_COMPILER}${_boost_MULTITHREADED}${_boost_STATIC_TAG}-${Boost_LIB_VERSION}
-                 ${Boost_LIB_PREFIX}boost_${COMPONENT}${_boost_MULTITHREADED}
-                 ${Boost_LIB_PREFIX}boost_${COMPONENT}${_boost_MULTITHREADED}${_boost_STATIC_TAG}
-                 ${Boost_LIB_PREFIX}boost_${COMPONENT}
-      )
-    ENDIF( NOT ${Boost_${UPPERCOMPONENT}_LIBRARY_RELEASE} )
-
     FIND_LIBRARY(Boost_${UPPERCOMPONENT}_LIBRARY_DEBUG
         NAMES  ${Boost_LIB_PREFIX}boost_${COMPONENT}${_boost_COMPILER}${_boost_MULTITHREADED}-${_boost_ABI_TAG}-${Boost_LIB_VERSION}
                ${Boost_LIB_PREFIX}boost_${COMPONENT}${_boost_COMPILER}${_boost_MULTITHREADED}${_boost_STATIC_TAG}${_boost_ABI_TAG}-${Boost_LIB_VERSION}
                ${Boost_LIB_PREFIX}boost_${COMPONENT}${_boost_MULTITHREADED}-${_boost_ABI_TAG}
                ${Boost_LIB_PREFIX}boost_${COMPONENT}${_boost_MULTITHREADED}${_boost_STATIC_TAG}${_boost_ABI_TAG}
                ${Boost_LIB_PREFIX}boost_${COMPONENT}-${_boost_ABI_TAG}
-        PATHS  ${_boost_LIBRARIES_SEARCH_DIRS}
-        NO_DEFAULT_PATH
+        HINTS  ${_boost_LIBRARIES_SEARCH_DIRS}
     )
 
-    IF( NOT ${Boost_${UPPERCOMPONENT}_LIBRARY_DEBUG} )
-      FIND_LIBRARY(Boost_${UPPERCOMPONENT}_LIBRARY_DEBUG
-          NAMES  ${Boost_LIB_PREFIX}boost_${COMPONENT}${_boost_COMPILER}${_boost_MULTITHREADED}-${_boost_ABI_TAG}-${Boost_LIB_VERSION}
-               ${Boost_LIB_PREFIX}boost_${COMPONENT}${_boost_COMPILER}${_boost_MULTITHREADED}${_boost_STATIC_TAG}${_boost_ABI_TAG}-${Boost_LIB_VERSION}
-               ${Boost_LIB_PREFIX}boost_${COMPONENT}${_boost_MULTITHREADED}-${_boost_ABI_TAG}
-               ${Boost_LIB_PREFIX}boost_${COMPONENT}${_boost_MULTITHREADED}${_boost_STATIC_TAG}${_boost_ABI_TAG}
-               ${Boost_LIB_PREFIX}boost_${COMPONENT}-${_boost_ABI_TAG}
-      )
-    ENDIF( NOT ${Boost_${UPPERCOMPONENT}_LIBRARY_DEBUG} )
     _Boost_ADJUST_LIB_VARS(${UPPERCOMPONENT})
     IF( Boost_USE_STATIC_LIBS )
       SET(CMAKE_FIND_LIBRARY_SUFFIXES ${_boost_ORIG_CMAKE_FIND_LIBRARY_SUFFIXES})
@@ -469,33 +448,103 @@ ELSE (_boost_IN_CACHE)
     ${Boost_INCLUDE_DIR}
   )
 
-  # MESSAGE(STATUS "Boost_INCLUDE_DIRS: ${Boost_INCLUDE_DIRS}")
-  # MESSAGE(STATUS "Boost_LIBRARIES: ${Boost_LIBRARIES}")
-
   SET(Boost_FOUND FALSE)
   IF(Boost_INCLUDE_DIR)
     SET( Boost_FOUND TRUE )
-    IF( Boost_FIND_VERSION_MAJOR AND Boost_MAJOR_VERSION LESS "${Boost_FIND_VERSION_MAJOR}" )
-      SET( Boost_FOUND FALSE )
-    ELSE( Boost_FIND_VERSION_MAJOR AND Boost_MAJOR_VERSION LESS "${Boost_FIND_VERSION_MAJOR}" )
-      IF( Boost_FIND_VERSION_MINOR AND Boost_MINOR_VERSION LESS "${Boost_FIND_VERSION_MINOR}" )
-        SET( Boost_FOUND FALSE )
-      ELSE( Boost_FIND_VERSION_MINOR AND Boost_MINOR_VERSION LESS "${Boost_FIND_VERSION_MINOR}" )
-        IF( Boost_FIND_VERSION_PATCH AND Boost_SUBMINOR_VERSION LESS "${Boost_FIND_VERSION_PATCH}" )
-          SET( Boost_FOUND FALSE )
-        ENDIF( Boost_FIND_VERSION_PATCH AND Boost_SUBMINOR_VERSION LESS "${Boost_FIND_VERSION_PATCH}" )
-      ENDIF( Boost_FIND_VERSION_MINOR AND Boost_MINOR_VERSION LESS "${Boost_FIND_VERSION_MINOR}" )
-    ENDIF( Boost_FIND_VERSION_MAJOR AND Boost_MAJOR_VERSION LESS "${Boost_FIND_VERSION_MAJOR}" )
-    set(_boost_CHECKED_COMPONENT FALSE)
-    FOREACH(COMPONENT ${Boost_FIND_COMPONENTS})
-      STRING(TOUPPER ${COMPONENT} COMPONENT)
-      set(_boost_CHECKED_COMPONENT TRUE)
-      IF(NOT Boost_${COMPONENT}_FOUND)
-        SET( Boost_FOUND FALSE)
-      ENDIF(NOT Boost_${COMPONENT}_FOUND)
-    ENDFOREACH(COMPONENT)
+
+    # Check the version of Boost against the requested version.
+    if (Boost_FIND_VERSION AND NOT Boost_FIND_VERSION_MINOR)
+      message(SEND_ERROR "When requesting a specific version of Boost, you must provide at least the major and minor version numbers, e.g., 1.34")
+    endif (Boost_FIND_VERSION AND NOT Boost_FIND_VERSION_MINOR)
+    if(Boost_MAJOR_VERSION LESS "${Boost_FIND_VERSION_MAJOR}" )
+      set( Boost_FOUND FALSE )
+      set(_Boost_VERSION_AGE "old")
+    elseif(Boost_MAJOR_VERSION EQUAL "${Boost_FIND_VERSION_MAJOR}" )
+      if(Boost_MINOR_VERSION LESS "${Boost_FIND_VERSION_MINOR}" )
+        set( Boost_FOUND FALSE )
+        set(_Boost_VERSION_AGE "old")
+      elseif(Boost_MINOR_VERSION EQUAL "${Boost_FIND_VERSION_MINOR}" )
+        if( Boost_FIND_VERSION_PATCH AND Boost_SUBMINOR_VERSION LESS "${Boost_FIND_VERSION_PATCH}" )
+          set( Boost_FOUND FALSE )
+          set(_Boost_VERSION_AGE "old")
+        endif( Boost_FIND_VERSION_PATCH AND Boost_SUBMINOR_VERSION LESS "${Boost_FIND_VERSION_PATCH}" )
+      endif( Boost_MINOR_VERSION LESS "${Boost_FIND_VERSION_MINOR}" )
+    endif( Boost_MAJOR_VERSION LESS "${Boost_FIND_VERSION_MAJOR}" )
+
+    if (Boost_FOUND AND Boost_FIND_VERSION_EXACT)
+      # If the user requested an exact version of Boost, check
+      # that. We already know that the Boost version we have is >= the
+      # requested version.
+      set(_Boost_VERSION_AGE "new")
+
+      # If the user didn't specify a patchlevel, it's 0.
+      if (NOT Boost_FIND_VERSION_PATCH)
+        set(Boost_FIND_VERSION_PATCH 0)
+      endif (NOT Boost_FIND_VERSION_PATCH)
+      
+      # We'll set Boost_FOUND true again if we have an exact version match.
+      set(Boost_FOUND FALSE)
+      if(Boost_MAJOR_VERSION EQUAL "${Boost_FIND_VERSION_MAJOR}" )
+        if(Boost_MINOR_VERSION EQUAL "${Boost_FIND_VERSION_MINOR}" )
+          if(Boost_SUBMINOR_VERSION EQUAL "${Boost_FIND_VERSION_PATCH}" )
+            set( Boost_FOUND TRUE )
+          endif(Boost_SUBMINOR_VERSION EQUAL "${Boost_FIND_VERSION_PATCH}" )
+        endif( Boost_MINOR_VERSION EQUAL "${Boost_FIND_VERSION_MINOR}" )
+      endif( Boost_MAJOR_VERSION EQUAL "${Boost_FIND_VERSION_MAJOR}" )
+    endif (Boost_FOUND AND Boost_FIND_VERSION_EXACT)
+
+    if(NOT Boost_FOUND)
+      # State that we found a version of Boost that is too new or too old.
+      set(Boost_ERROR_REASON
+        "${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)
+        set(Boost_ERROR_REASON 
+          "${Boost_ERROR_REASON}.${Boost_FIND_VERSION_PATCH}")
+      endif (Boost_FIND_VERSION_PATCH)
+      if (NOT Boost_FIND_VERSION_EXACT)
+        set(Boost_ERROR_REASON "${Boost_ERROR_REASON} (or newer)")
+      endif (NOT Boost_FIND_VERSION_EXACT)
+      set(Boost_ERROR_REASON "${Boost_ERROR_REASON}.")
+    endif (NOT Boost_FOUND)
+
+    if (Boost_FOUND)
+      set(_boost_CHECKED_COMPONENT FALSE)
+      set(_Boost_MISSING_COMPONENTS)
+      foreach(COMPONENT ${Boost_FIND_COMPONENTS})
+        string(TOUPPER ${COMPONENT} COMPONENT)
+        set(_boost_CHECKED_COMPONENT TRUE)
+        if(NOT Boost_${COMPONENT}_FOUND)
+          string(TOLOWER ${COMPONENT} COMPONENT)
+          list(APPEND _Boost_MISSING_COMPONENTS ${COMPONENT})
+          set( Boost_FOUND FALSE)
+        endif(NOT Boost_${COMPONENT}_FOUND)
+      endforeach(COMPONENT)
+    endif (Boost_FOUND)
+
+    if (_Boost_MISSING_COMPONENTS)
+      # We were unable to find some libraries, so generate a sensible
+      # error message that lists the libraries we were unable to find.
+      set(Boost_ERROR_REASON
+        "${Boost_ERROR_REASON}\nThe following Boost libraries could not be found:\n")
+      foreach(COMPONENT ${_Boost_MISSING_COMPONENTS})
+        set(Boost_ERROR_REASON
+          "${Boost_ERROR_REASON}        boost_${COMPONENT}\n")
+      endforeach(COMPONENT)
+
+      list(LENGTH Boost_FIND_COMPONENTS Boost_NUM_COMPONENTS_WANTED)
+      list(LENGTH _Boost_MISSING_COMPONENTS Boost_NUM_MISSING_COMPONENTS)
+      if (${Boost_NUM_COMPONENTS_WANTED} EQUAL ${Boost_NUM_MISSING_COMPONENTS})
+        set(Boost_ERROR_REASON
+          "${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 (${Boost_NUM_COMPONENTS_WANTED} EQUAL ${Boost_NUM_MISSING_COMPONENTS})
+        set(Boost_ERROR_REASON
+          "${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 (${Boost_NUM_COMPONENTS_WANTED} EQUAL ${Boost_NUM_MISSING_COMPONENTS})
+    endif (_Boost_MISSING_COMPONENTS)
+
     IF( NOT Boost_LIBRARY_DIRS AND NOT _boost_CHECKED_COMPONENT )
-      # Compatibility Code for backwards compatibility with CMake 2.4
+      # 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
@@ -549,8 +598,7 @@ ELSE (_boost_IN_CACHE)
       ENDFOREACH(COMPONENT)
   ELSE (Boost_FOUND)
       IF (Boost_FIND_REQUIRED)
-        MESSAGE(STATUS "Boost version required: ${Boost_FIND_VERSION_MAJOR}.${Boost_FIND_VERSION_MINOR}.${Boost_FIND_VERSION_PATCH}, found: ${Boost_MAJOR_VERSION}.${Boost_MINOR_VERSION}.${Boost_SUBMINOR_VERSION}")
-        MESSAGE(FATAL_ERROR "Couldn't find the Boost libraries and/or include directory, or the version found is too old. Please install the Boost libraries AND development packages. You can set BOOST_ROOT, BOOST_INCLUDEDIR and BOOST_LIBRARYDIR to help find Boost.")
+        message(SEND_ERROR "Unable to find the requested Boost libraries.\n${Boost_ERROR_REASON}")
       ENDIF(Boost_FIND_REQUIRED)
   ENDIF(Boost_FOUND)