CMakeLists.txt的简单使用

参考：http://blog.csdn.net/cust_hf/article/category/345853

(1):要求CMake根据指定的源文件生成可执行文件

Demo1:

add_executable(hello main.cpp)

    这将从main.cpp源码文件创建一个叫“hello”（Windows下叫“hello.exe”）的可执行文件。你可以根据自己的需要将C和C++文件混合。在同一个CMakeLists.txt可以有多个可执行文件和库。同一个源码文件可以用于不同的目的，源码可以从其他目标中为每个目的独立的编译。 

Demo2:

add_executable(demo main.cpp main.h main.rc)

    这奖使用main.cpp源文件,main.h文件,main.rc文件构造可执行文件。至于如何使用这些文件,CMake比我们都清楚。

 

(2):调试CMakeLists.txt的办法 
这个是调试CMakeLists.txt的一个手段啦。不得不学习哦。 

演示1如下:
MESSAGE("俺们正在生成项目文件")
会显示一个警告框。

演示2如下:
MESSAGE(STATUS "俺们正在创建项目文件")
遇到这条指令,会把文字显示在状态栏里面(一闪而过，不容易发现)。

演示3如下:
MESSAGE(FATAL_ERROR "严重错误，俺们搞不定啦")
这条指令会提示出错，并退出。

(3):使用标准模块 
cmake提供了很多标准模块，扩展名都是txt.我们可以直接包含进来。就像使用C语言的#include指令一般。比如:
INCLUDE(FindBoost)
一句话,就告诉了CMake“我们的程序需要Boost”。

(4):使用变量 .
SET( MY_SOURCES main.cpp widget.cpp)
MESSAGE(STATUS "my sources: ${MY_SOURCES}")使用SET()命令来为变量设置值。如果你列出了一个以上的字符串，变量将是串列表。列表是一列由分号隔开的字符串。如果只设置个一项，那么这项只有一个值。可以通过${VAR}获得变量的值。可以使用FOREACH()来迭代一份列表：

FOREACH(next_ITEM ${MY_SOURCES})
   MESSAGE(STATUS "next item: ${next_ITEM}")
ENDFOREACH(next_ITEM ${MY_SOURCES})

CMake中的命令是大小写无关的。变量名和参数名是大小写相关的。

(5):测试平台相关信息 .
办法一(这个代码没有检验过哦) 
IF (UNIX)
   MESSAGE("这个是UNIX操作系统")
ENDIF (UNIX)
 
IF (MSVC)
   MESSAGE("这个需要做VC的项目文件")
ENDIF (MSVC)

办法二(这个测试过)

IF (${CMAKE_SYSTEM_NAME} STREQUAL "Windows")
 SET(option WIN32)
 SET(win32_LIBRARIES comctl32.lib shlwapi.lib shell32.lib odbc32.lib odbccp32.lib  kernel32.lib user32.lib gdi32.lib winspool.lib comdlg32.lib advapi32.lib shell32.lib ole32.lib oleaut32.lib uuid.lib odbc32.lib odbccp32.lib)
 #SET(defs -DUNICODE -D_UNICODE)
ENDIF (${CMAKE_SYSTEM_NAME} STREQUAL "Windows")

(6):要求CMake根据指定的源文件生成库文件 .
ADD_LIBRARY: Add a library to the project using the specified source files.

  ADD_LIBRARY(libname [SHARED | STATIC | MODULE] [EXCLUDE_FROM_ALL]              source1 source2 ... sourceN)Adds a library target. SHARED, STATIC or MODULE keywords are used to set the library type. If the keyword MODULE appears, the library type is set to MH_BUNDLE on systems which use dyld. On systems without dyld, MODULE is treated like SHARED. If no keywords appear as the second argument, the type defaults to the current value of BUILD_SHARED_LIBS. If this variable is not set, the type defaults to STATIC.

If EXCLUDE_FROM_ALL is given the target will not be built by default. It will be built only if the user explicitly builds the target or another target that requires the target depends on it.

(7):添加查找头文件的路径 .
INCLUDE_DIRECTORIES: Add include directories to the build.

  INCLUDE_DIRECTORIES([AFTER|BEFORE] [SYSTEM] dir1 dir2 ...)Add the given directories to those searched by the compiler for include files. By default the directories are appended onto the current list of directories. This default behavior can be changed by setting CMAKE_INCLUDE_DIRECTORIES_BEFORE to ON. By using BEFORE or AFTER you can select between appending and prepending, independent from the default. If the SYSTEM option is given the compiler will be told that the directories are meant as system include directories on some platforms. 

(8):添加库文件的搜索路径 .
分类： CMake相关 2007-11-04 00:50 421人阅读 评论(0) 收藏 举报 
LINK_DIRECTORIES: Specify directories in which to search for libraries.

  LINK_DIRECTORIES(directory1 directory2 ...)

(9):显式指定链接时需要的库文件 .
分类： CMake相关 2007-11-04 00:54 491人阅读 评论(0) 收藏 举报 
为每个目标分别指定需要链接的库文件(指定部分目标专用的库文件)
 TARGET_LINK_LIBRARIES: Link a target to given libraries.

  TARGET_LINK_LIBRARIES(target library1                        <debug | optimized> library2                        ...)Specify a list of libraries to be linked into the specified target. The debug and optimized strings may be used to indicate that the next library listed is to be used only for that specific type of build

为所有目标统一指定需要的库文件(指定所有目标都用的库文件)
LINK_LIBRARIES: Link libraries to all targets added later.

  LINK_LIBRARIES(library1 <debug | optimized> library2 ...)This is an old CMake command for linking libraries. Use TARGET_LINK_LIBRARIES unless you have a good reason for every target to link to the same set of libraries.

Specify a list of libraries to be linked into any following targets (typically added with the ADD_EXECUTABLE or ADD_LIBRARY calls). This command is passed down to all subdirectories. The debug and optimized strings may be used to indicate that the next library listed is to be used only for that specific type of build.

(10):显式实施宏定义 .
用法演示一(文本宏):

ADD_DEFINITIONS(-DDEBUG) 

用法演示二(常量宏)

ADD_DEFINITIONS(-DVERSION=1) 

 ADD_DEFINITIONS: Adds -D define flags to the command line of C and C++ compilers.
  ADD_DEFINITIONS(-DFOO -DBAR ...)Adds flags to command line of C and C++ compilers. This command can be used to add any flag to a compile line, but the -D flag is accepted most C/C++ compilers. Other flags may not be as portable.

(11)让编译者在界面上设置你提供的选项

#增加一个选项,WXWINDOWS_USE_SHARED_LIBS
    (WXWINDOWS_USE_SHARED_LIBS "Use shared versions (.so) of wxWindows libraries" ON)
    MARK_AS_ADVANCED(WXWINDOWS_USE_SHARED_LIBS) 

 OPTION: Provides an option that the user can optionally select.

•   OPTION(OPTION_VAR "help string describing option"
           [initial value])

  Provide an option for the user to select as ON or OFF. If no initial value is provided, OFF is used.

(12)查找特定软件的安装目录

FIND_PATH(WxRoot NAMES ${CharacteristicFilesOfWx} PATHS ${DirectorOfWxMyBe})

MESSAGE(${WxRoot})

 

 FIND_PATH: Find the directory containing a file.

   FIND_PATH(<VAR> name1 path1 path2 ...)

(13)查找库

FIND_PACKAGE(ZLIB REQUIRED)

查找一个库，库的名字是ZLIB，后面的REQUIRED是可选项，表示这个包是必须的，如果找不到不能生成Makefile。有了这句以后，一定有一个对应的FindZLIB.cmake，在这个文件里面，会有具体的如何查找ZLIB。

FIND_PATH(ZLIB_INCLUDE_DIR zlib.h “/home/release/arm11/include” NO_CMAKE_SYSTEM_PATH)

这句话应该出现在FindZLIB.cmake里面，表示在目录“/home/release/arm11/include”下查找文件zlib.h，找到以后，把路径放到变量ZLIB_INCLUDE_DIR里面。如果有多个目录，用空格或者换行分开放在后面就可以了，最好用引号引起来。

cmake的使用：http://blog.chinaunix.net/uid-23381466-id-3826931.html