从头开始构建一个带第三方库的cmake

程序目录文件

root@aw:~/test# tree .
.
├── libsupp             # 第三方库文件和头文件
│   ├── include
│   │   └── jansson.h
│   └── lib
│       └── libjansson.a
└── src
    └── main.c          # 自己项目的源文件

首先确定cmake最低版本
1
cmake_minimum_required(VERSION 2.8)
确定项目名
1
project(hello)
设置语言标准
1
set(CMAKE_C_STANDARD 99)

设置编译选项

1	set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall -g -D_GNU_SOURCE")

指定源文件目录

1 2	# ${CMAKE_CURRENT_LIST_DIR}表示CMakeLists.txt文件所在目录 aux_source_directories(${CMAKE_CURRENT_LIST_DIR}/src SOURCE_FILES)

指定头文件目录

1	include_directories(${CMAKE_CURRENT_LIST_DIR}/libsupp/include)

指定第三方库文件目录

1	link_directories(${CMAKE_CURRENT_LIST_DIR}/libsupp/lib)

指定目标文件

1	add_executable(${PROJECT_NAME} ${SOURCE_FILES})

需要引用第三方库

1	target_link_libraries(${PROJECT_NAME} jansson)

有时候cmake会报不认识链接库语言的错，加上这个

1	set_target_properties(${PROJECT_NAME} PROPERTIES LINKER_LANGUAGE C)

合起来就是下边这个CMakeLists.txt

cmake_minimum_required(VERSION 2.8)
project(hello)

#set(CMAKE_CXX_STANDARD 11)
# 设置系统标准
set(CMAKE_C_STANDARD 99)

# 设置编译选项
set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall -g  -D_GNU_SOURCE")

# 指定源文件目录
aux_source_directory(${CMAKE_CURRENT_LIST_DIR}/src SOURCE_FILES)

# 指定头文件目录
include_directories(${CMAKE_CURRENT_LIST_DIR}/libsupp/include)

# 指定第三方库文件目录
link_directories(${CMAKE_CURRENT_LIST_DIR}/libsupp/lib)

# 指定目标文件
add_executable(${PROJECT_NAME} ${SOURCE_FILES})

# 引用第三方库
target_link_libraries(${PROJECT_NAME} jansson)

# 设置第三方库的语言
set_target_properties(traceroute_k PROPERTIES LINKER_LANGUAGE C)

出现这个错

-- The CXX compiler identification is unknown
CMake Error at CMakeLists.txt:2 (PROJECT):
  No CMAKE_CXX_COMPILER could be found.

  Tell CMake where to find the compiler by setting either the environment
  variable "CXX" or the CMake cache entry CMAKE_CXX_COMPILER to the full path
  to the compiler, or to the compiler name if it is in the PATH.


-- Configuring incomplete, errors occurred!
See also "/ioda/ipwave_rt/bgpstream/build/CMakeFiles/CMakeOutput.log".
See also "/ioda/ipwave_rt/bgpstream/build/CMakeFiles/CMakeError.log".

但是我的项目是纯C的，用不到CXX，可以设置项目语言为C

1	PROJECT(hello LANGUAGES C)

CheckCxxCompilerFlag 模块

检查cxx编译器是否支持某个flag

include(CheckCxxCompilerFlag)
CHECK_CXX_COMPILER_FLAG("-std=c++1" COMPILER_SUPPORTS_CXX11)
if (COMPILER_SUPPORTS_CXX11)
    set(CMAKE_CXX_FLAGS ${CMAKE_CXX_FLAGS} "-std=c++1")
else()
    message(FATAL "not support c++11.")
endif()

示例

cmake_minimum_required(VERSION 3.0)
project(ua)

set(CMAKE_CXX_STANDARD 11)


add_executable(${PROJECT_NAME} ua.c)
target_link_libraries(${PROJECT_NAME} PUBLIC eXosip2 osip2 osipparser2 pthread)
target_include_directories(${PROJECT_NAME} PUBLIC ${CMAKE_SOURCE_DIR}/deps/include )
target_link_directories(${PROJECT_NAME} PUBLIC ${CMAKE_SOURCE_DIR}/deps/lib)

引入第三方库

add_custom_target(third)

externalproject_add(
    deps_osip2
    PREFIX ${CMAKE_BINARY_DIR}/deps/
    URL ${CMAKE_SOURCE_DIR}/deps/libosip2-5.0.0.tar.gz
    CONFIGURE_COMMAND ./configure --prefix=${CMAKE_BINARY_DIR}/deps/
    BUILD_COMMAND make -j2
    BUILD_IN_SOURCE 1
    INSTALL_COMMAND make install
)

add_dependencies(third deps_osip2)
add_executable(${PROJECT_NAME} ua.c)
add_dependencies(${PROJECT_NAME} third)
target_link_libraries(${PROJECT_NAME} PUBLIC
    ${CMAKE_BINARY_DIR}/deps/lib/libeXosip2.a
    ${CMAKE_BINARY_DIR}/deps/lib/libosip2.a
    ${CMAKE_BINARY_DIR}/deps/lib/libosipparser2.a pthread ssl crypto resolv)
target_include_directories(${PROJECT_NAME} PUBLIC ${CMAKE_BINARY_DIR}/deps/include)

memo

cmake_minimum_required(VERSION 2.8)

project(sokk)

指定编译器标准 –std=c++11
set(CMAKE_CXX_FLAGS “${CMAKE_CXX_FLAGS} -std=c++11”)
指定编译选项
set(CMAKE_CXX_FLAGS “${CMAKE_CXX_FLAGS} -g -Wall”)
打开详细输出
set(CMAKE_VERBOSE_MAKEFILE ON)
生成DEBUG
set(CMAKE_BUILD_TYPE DEBUG)
控制宏定义
add_definitions(-DSPDLOG_HEADER_ONLY=1)

set(SRC src/sokk.cpp)
set(DEPS_STATIC deps/libhv/lib/libhv_static.a)

链接静态库，需要指明具体地址
add_executable(sokk ${SRC} ${DEPS_STATIC})
链接动态库
target_include_directories(sokk
PUBLIC ${CMAKE_SOURCE_DIR}/deps/libhv/include)

安装

安装目录
set(CMAKE_INSTALL_PREFIX ${PROJECT_SOURCE_DIR}/install)
install(DIRECTORY ${PROJECT_SOURCE_DIR}/etc DESTINATION . PATTERN etc/*.json EXCLUDE)
install(FILES ${PROJECT_SOURCE_DIR}/README.md DESTINATION .)

cache 变量

normal variable: 普通变量，局部作用域
cache variable: 缓存变量，全局变量, 同一个CMAKE功能任何地方都可以用

set( … CACHE [FORCE])
variable：变量名称
value：变量值列表
CACHE：cache变量的标志
type：变量类型，取决于变量的值。类型分为：BOOL、FILEPATH、PATH、STRING、INTERNAL
docstring：必须是字符串，作为变量概要说明
FORCE：强制选项，强制修改变量值

Morning~Sun.

用到的cmake

CheckCxxCompilerFlag 模块

示例

引入第三方库

memo

安装

cache 变量