CMakeList笔记

• 定义

  CMake是一种跨平台编译工具，CMake主要是编写CMakeLists.txt文件，然后通过cmake命令将CMakeLists.txt文件转化为make所需要的Makefile文件，最后用make命令编译源码生成可执行程序或者库文件。

• 语法规则

  指令是大小写无关的，参数和变量是大小写相关的

  • CMakeLists.txt常见指令
    1、cmake_minimum_required(VERSION 2.6)命令
    #指定CMake编译最低要求版本
    例：CMAKE_MINIMUM_REQUIRED(VERSION 3.14)

    2、PROJECT()命令
    #给项目命名
    PROJECT(TEST)

    3、ADD_SUBDIRECTORY命令
    #该命令告诉CMake去子目录中查看可用的CMakeLists.txt文件

    4、ADD_EXECUTABLE命令
    #将hello.cpp生成可执行文件hello
    ADD_EXECUTABLE(hello ${SOURCE})

    5、ADD_LIBRARY命令
    #变量SRC_LIST_CPP 与SRC_LIST_C 指定生成test动态库 默认生成静态库 SHARED指定生成库类型为动态库
    ADD_LIBRARY(test SHARED ${SRC_LIST_CPP} ${SRC_LIST_C})
    ADD_LIBRARY(test STATIC util.cpp) # 生成静态库

    6、FILE命令
    #收集c/c++文件并赋值给变量SRC_LIST_CPP ${PROJECT_SOURCE_DIR}代表区当前项目录
    FILE(GLOB SRC_LIST_CPP ${PROJECT_SOURCE_DIR}/src/*.cpp)

    7、INCLUDE_DIRECTORIES命令
    #指定头文件目录
    INCLUDE_DIRECTORIES(${PROJECT_SOURCE_DIR}/include)

    8、LINK_DIRECTORIES命令
    #指定链接库文件目录
    LINK_DIRECTORIES(${PROJECT_SOURCE_DIR}/lib)

    9、TARGET_LINK_LIBRARIES命令
    #指定hello 链接库test
    TARGET_LINK_LIBRARIES(hello test)

    10、AUX_SOURCE_DIRECTORY命令
    #AUX_SOURCE_DIRECTORY(dir VAR) 发现一个目录下所有的源代码文件并将列表存储在一个变量中
    AUX_SOURCE_DIRECTORY(. SRC_LIST) # 搜索当前目录下的所有.cpp文件，放到SRC_LIST变量中

    8、SET命令
    #用来显式的定义变量
    例子：
    #用变量代替值，例子中定义SRC_LST代替后面的字符串
    SET (SRC_LST main.c test.c)
    #指定生成库文件的目录
    SET(LIBRARY_OUTPUT_PATH ${PROJECT_SOURCE_DIR}/lib)

    • 常用变量

    变量名	含义
    JECT_NAME	project命令中写的项目名
    KE_VERSION	当前使用CMake的版本
    KE_SOURCE_DIR	工程顶层目录，即入口CMakeLists文件所在路径
    JECT_SOURCE_DIR	同CMAKE_SOURCE_DIR
    KE_BINARY_DIR	工程编译发生的目录，即执行cmake命令进行项目配置的目录，一般为build
    JECT_BINARY_DIR	同CMAKE_BINARY_DIR
    KE_CURRENT_SOURCE_DIR	当前处理的CMakeLists.txt所在的路径
    KE_CURRRENT_BINARY_DIR	当前处理的CMakeLists.txt中生成目标文件所在编译目录
    KE_CURRENT_LIST_FILE	输出调用这个变量的CMakeLists.txt文件的完整路径
    KE_CURRENT_LIST_DIR	当前处理的CMakeLists.txt文件所在目录的路径
    KE_INSTALL_PREFIX	指定make install命令执行时包安装路径
    KE_MODULE_PATH	find_package命令搜索包路径之一，默认为空
    KE_BUILD_TYPE	编译选项，Release或者Debug，如set(CMAKE_BUILD_TYPE “Release”)
    KE_CXX_FLAGS	编译标志，设置C++11编译，set(CMAKE_CXX_FLAGS “${CMAKE_CXX_FLAGS} -std=c++11”)

• 例子

#指定CMake编译最低要求版本3.6
cmake_minimum_required(VERSION 3.6)

#CMAKE_BUILD_TYPE 代替后面的字符串RelWithDebInfo CACHE STRING "build type"
set(CMAKE_BUILD_TYPE RelWithDebInfo CACHE STRING "build type")

#给项目命名tutorial
project(tutorial
		LANGUAGES C CXX
)

#CMAKE_RUNTIME_OUTPUT_DIRECTORY 代替后面的字符串${PROJECT_SOURCE_DIR}
set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${PROJECT_SOURCE_DIR})

if(ANDROID)
	#指定链接库文件目录${OPENSSL_LINK_DIR}
	link_directories(${OPENSSL_LINK_DIR})
else()
	find_library(LIBRT rt)
	find_package(OpenSSL REQUIRED)
endif()
find_package(workflow REQUIRED CONFIG HINTS ..)
#指定头文件目录${OPENSSL_INCLUDE_DIR} ${WORKFLOW_INCLUDE_DIR}
include_directories(${OPENSSL_INCLUDE_DIR} ${WORKFLOW_INCLUDE_DIR})
#指定链接库文件目录${WORKFLOW_LIB_DIR}
link_directories(${WORKFLOW_LIB_DIR})

if (KAFKA STREQUAL "y")
	find_path(SNAPPY_INCLUDE_PATH NAMES snappy.h)
	#指定头文件目录${SNAPPY_INCLUDE_PATH}
	include_directories(${SNAPPY_INCLUDE_PATH})
endif ()

if (WIN32)
		set(CMAKE_C_FLAGS   "${CMAKE_C_FLAGS}   /MP /wd4200")
		set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /MP /wd4200 /std:c++14")
else ()
		#CMAKE_C_FLAGS代替后面的字符串"${CMAKE_C_FLAGS}   -Wall -fPIC -pipe -std=gnu90"
		set(CMAKE_C_FLAGS   "${CMAKE_C_FLAGS}   -Wall -fPIC -pipe -std=gnu90")
		set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -fPIC -pipe -std=c++11 -fno-exceptions")
endif ()

#TUTORIAL_LIST代替后面的字符串
set(TUTORIAL_LIST
	tutorial-00-helloworld
	tutorial-01-wget
	tutorial-04-http_echo_server
	tutorial-05-http_proxy
	tutorial-06-parallel_wget
	tutorial-07-sort_task
	tutorial-08-matrix_multiply
	tutorial-09-http_file_server
	tutorial-11-graph_task
	tutorial-15-name_service
	tutorial-20-reducer
)

if (APPLE)
	set(WORKFLOW_LIB workflow pthread OpenSSL::SSL OpenSSL::Crypto)
elseif (ANDROID)
	set(WORKFLOW_LIB workflow ssl crypto c)
else ()
	set(WORKFLOW_LIB workflow pthread OpenSSL::SSL OpenSSL::Crypto ${LIBRT})
endif ()

foreach(src ${TUTORIAL_LIST})
	string(REPLACE "-" ";" arr ${src})
	list(GET arr -1 bin_name)
	#将${src}.cc生成可执行文件${bin_name} 
	add_executable(${bin_name} ${src}.cc)
	#指定${bin_name}链接库${WORKFLOW_LIB}
	target_link_libraries(${bin_name} ${WORKFLOW_LIB})
endforeach()

if (NOT REDIS STREQUAL "n")
set(TUTORIAL_LIST
	tutorial-02-redis_cli
	tutorial-03-wget_to_redis
)
foreach(src ${TUTORIAL_LIST})
	string(REPLACE "-" ";" arr ${src})
	list(GET arr -1 bin_name)
	add_executable(${bin_name} ${src}.cc)
	
	target_link_libraries(${bin_name} ${WORKFLOW_LIB})
endforeach()
endif()

if (NOT MYSQL STREQUAL "n")
set(TUTORIAL_LIST
	tutorial-12-mysql_cli
)
foreach(src ${TUTORIAL_LIST})
	string(REPLACE "-" ";" arr ${src})
	list(GET arr -1 bin_name)
	add_executable(${bin_name} ${src}.cc)
	target_link_libraries(${bin_name} ${WORKFLOW_LIB})
endforeach()
endif()

if (KAFKA STREQUAL "y")
	add_executable("kafka_cli" "tutorial-13-kafka_cli.cc")
	target_link_libraries("kafka_cli" wfkafka ${WORKFLOW_LIB} z snappy lz4 zstd)
endif ()

set(DIR10 tutorial-10-user_defined_protocol)
add_executable(server ${DIR10}/server.cc ${DIR10}/message.cc)
add_executable(client ${DIR10}/client.cc ${DIR10}/message.cc)
target_link_libraries(server ${WORKFLOW_LIB})
target_link_libraries(client ${WORKFLOW_LIB})

set_target_properties(server PROPERTIES
	RUNTIME_OUTPUT_DIRECTORY ${PROJECT_SOURCE_DIR}/${DIR10})
set_target_properties(client PROPERTIES
	RUNTIME_OUTPUT_DIRECTORY ${PROJECT_SOURCE_DIR}/${DIR10})