[手游新项目历程]第16天-cmake

#win32->linux注意事项

#linux fprintf 需要加入#include <stdio.h> 头文件，而win32不需要

#--linux关键字
cmake_minimum_required(VERSION 3.5.1)		#版本号
project(Gate)								#工程名
add_executable(Gate Gate.cpp)				#生成exe文件
add_library(AddFunction AddFunction.cpp)	#add_library 生成lib库


set ( HelloCMake_VERSION_MAJOR 1 )		#定义c++的宏，类似于define HelloCMake_VERSION_MAJOR 1
			
configure_file(							#根据配置文件生成C++用的头文件

         "${PROJECT_SOURCE_DIR}/HelloCMakeConfig.h.in"	#(全路径/src) PROJECT_SOURCE_DIR 是工程源文件所在的目录

         "${PROJECT_BINARY_DIR}/HelloCMakeConfig.h"		#(全路径/build)

         )

#PROJECT_SOURCE_DIR 和 	PROJECT_BINARY_DIR区别   http://blog.csdn.net/sukhoi27smk/article/details/46388711	 
		 
#define HelloCMake_VERSION_MAJOR @HelloCMake_VERSION_MAJOR@	//定义在HelloCMakeConfig.h.in, 生成的头文件 HelloCMakeConfig.h 内容#define HelloCMake_VERSION_MAJOR 1


Include_directories ("${PROJECT_BINARY_DIR}") #路径(是工程源文件所在的目录)加入到工程头文件的搜索路径中去，这样工程编译链接时就能够找到HelloCMakeConfig.h这个头文件。

Include_directories 例子：
INCLUDE_DIRECTORIES(
  ${VTK_INCLUDE_DIRS_BUILD_TREE}
  ${VTK_INCLUDE_DIRS_SOURCE_TREE}
  ${VTK_INCLUDE_DIRS_BUILD_TREE_CXX}
  ${VTK_INCLUDE_DIRS_SYSTEM}
)

#define HelloCMake_VERSION_MAJOR @HelloCMake_VERSION_MAJOR@ #放在.h.in文件，@X@对X取值，取你宏定义的值 = define  HelloCMake_VERSION_MAJOR 1,


if (USE_AddFunction)										#if/endif语句块必须要成对出现，if和endif后面所带的参数也必须一致。				
  include_directories ("${PROJECT_SOURCE_DIR}/AddFunction")
  #add_subdirectory (AddFunction)							#为构建添加一个子路径  CMake:add_subdirectory(...)隐含的用法 http://www.cnblogs.com/Need4Speak/p/5418818.html
  set (EXTRA_LIBS ${EXTRA_LIBS} AddFunction)				#设置变量EXTRA_LIBS的值为AddFunction.lib
endif (USE_AddFunction)										#USE_AddFunction cmake宏定义 .h.in文件 #cmakedefine USE_AddFunction
	
#完整例子	
cmake_minimum_required (VERSION 2.8.3)
project (HelloCMake)

option(USE_AddFunction "Use our Add Function" ON)			#option是CMake里的命令，它的作用就是在CMake GUI上增加一个选项

set ( HelloCMake_VERSION_MAJOR 1 )
set ( HelloCMake_VERSION_MINOR 0 )

configure_file(
         "${PROJECT_SOURCE_DIR}/HelloCMakeConfig.h.in"
         "${PROJECT_BINARY_DIR}/HelloCMakeConfig.h"
         )
 
Include_directories ("${PROJECT_BINARY_DIR}")

if (USE_AddFunction)
  include_directories ("${PROJECT_SOURCE_DIR}/AddFunction")
  #add_subdirectory (AddFunction)
  set (EXTRA_LIBS ${EXTRA_LIBS} AddFunction)
endif (USE_AddFunction)

add_library(AddFunction AddFunction.cpp)
add_executable(HelloCMake HelloCMake.cpp)
target_link_libraries (HelloCMake ${EXTRA_LIBS})