cmake编译（编译目标）x86或x64

if(CMAKE_CL_64)    #CMAKE的内建变量，如果是true，就说明编译器的64位的，自然可以编译64bit的程序
set(ADDRESS_MODEL 64)
set(NODE_TARGET x64)
else()
set(ADDRESS_MODEL 32)
set(NODE_TARGET x86)
endif()

看以上代码，判断下就行了

CMAKE_CL_64内建的这个变量，官方文档给出来的解释是：

Using the 64 bit compiler from Microsoft

Set to true when using the 64 bit cl compiler from Microsoft.

###############update####################

如果是GCC编译器或者其他的诸如sun Studio之类的，可以设置CFLAGS CXXFLAGS变量，加入-m32 或者-m64来编译x86或者x64的程序。

如果是windows平台下VS的project文件的话，请使用VS generator，cmake -G "Visual Studio 10 Win64"就是编译为x64，cmake -G "Visual Studio 10 "就是编译为x86.

如果是Mac OS X上，使用CMAKE_OSX_ARCHITECTURES这个CMAKE的内建变量。

• cmake -DCMAKE_OSX_ARCHITECTURES=i386 /path/to/source/dir------编译为32位

  cmake -DCMAKE_OSX_ARCHITECTURES=x86_64 /path/to/source/dir------编译为64位

  cmake "-DCMAKE_OSX_ARCHITECTURES=x86_64;i386" /path/to/source/dir -------编译为通用8664架构和i386架构的二进制

或者可以用另外一种方式，思路是这样的，其实编译为x86或者x64，本质上都是向linker传递特定的参数。如果是VS,或者是NMake的Makefiles的话，直接使用CMAKE内建的变量CMAKE_EXE_LINKER_FLAGS,来设置链接器的参数。VS toolchain 可以这样 set(CMAKE_EXE_LINKER_FLAGS "/machine:x86")。

这个变量官方给出来的解释是：

Linker flags to be used to create executables.

These flags will be used by the linker when creating an executable.

以下是构建一个console的demo：

 SET(PROJECT_NAME dls_test)

 PROJECT(${PROJECT_NAME})

 CMAKE_MINIMUM_REQUIRED(VERSION 2.8)

 #ADD_DEFINITIONS(-DUNICODE -D_UNICODE)
 ADD_DEFINITIONS(-D_CONSOLE)

 SET(CMAKE_MFC_FLAG 1)  #0: Use Standard Windows Libraries            1: Use MFC in a Static Library        2: Use MFC in a Shared DLL

 include_directories(${PROJECT_SOURCE_DIR})
 include_directories(${PROJECT_SOURCE_DIR}/../inc)
 include_directories(${PROJECT_SOURCE_DIR}/../wlp_adapter)
 include_directories(${PROJECT_SOURCE_DIR}/../include)

 LINK_DIRECTORIES(${PROJECT_SOURCE_DIR}/../lib)
 #LINK_DIRECTORIES(${CMAKE_BINARY_DIR}/lib)

 file(GLOB SRC RELATIVE ${CMAKE_CURRENT_SOURCE_DIR}  main.cpp )
 source_group("src" FILES ${SRC})

 file(GLOB hdrs RELATIVE ${CMAKE_CURRENT_SOURCE_DIR} *.h)
 source_group("include" FILES ${hdrs})

 ADD_EXECUTABLE(${PROJECT_NAME}  ${SRC} ${hdrs})

 if(WIN32)
 if(CMAKE_BUILD_TYPE MATCHES "Debug")
   #set(OPENCV_LIB "opencv_core246d.lib" "opencv_highgui246d.lib" "opencv_imgproc246d.lib" IlmImfd.lib Comctl32.lib)
   TARGET_LINK_LIBRARIES(${PROJECT_NAME} wlp_adapter.lib hal.lib cbs.lib libglog_staticd.lib )
 else()
     TARGET_LINK_LIBRARIES(${PROJECT_NAME} wlp_adapter.lib hal.lib cbs.lib libglog_static.lib )
 endif()

 set_target_properties(${PROJECT_NAME} PROPERTIES LINK_FLAGS "/SUBSYSTEM:CONSOLE") 

 else()

    TARGET_LINK_LIBRARIES(${PROJECT_NAME} wlp_adapter hal cbs glog  pthread gomp rt glib-2.0 dl GL boost_system boost_filesystem boost_program_options boost_regex)

 endif()

 if(WIN32)
 else()
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}   -std=c++0x  -fPIC ")
 endif()

 set(CompilerFlags
         CMAKE_CXX_FLAGS
         CMAKE_CXX_FLAGS_DEBUG
         CMAKE_CXX_FLAGS_RELEASE
         CMAKE_C_FLAGS
         CMAKE_C_FLAGS_DEBUG
         CMAKE_C_FLAGS_RELEASE
         )
 foreach(CompilerFlag ${CompilerFlags})
   string(REPLACE "/MD" "/MT" ${CompilerFlag} "${${CompilerFlag}}")
   string(REPLACE "/Ob0" "" ${CompilerFlag} "${${CompilerFlag}}")
   string(REPLACE "/TC" "" ${CompilerFlag} "${${CompilerFlag}}")
 endforeach()

 INSTALL(TARGETS ${prj_name}
     RUNTIME DESTINATION bin
     LIBRARY DESTINATION lib
     ARCHIVE DESTINATION lib
 )

 install(DIRECTORY ${PROJECT_SOURCE_DIR}
     DESTINATION "."
     )

reference：

http://stackoverflow.com/questions/5334095/cmake-multiarchitecture-compilation

http://blog.csdn.net/wh_xiexing/article/details/18301923

http://www.cmake.org/cmake/help/v3.0/variable/CMAKE_CL_64.html

http://www.cmake.org/cmake/help/v3.0/variable/CMAKE_EXE_LINKER_FLAGS.html