利用CMake搭建软件编译架构

0 写在前面的话

本博文主要介绍如何利用cmake组织软件编译，并且提供一个简单的软件编译架构的模板。大家可以根据自己实际情况进行改动，本文主要的内容：

cmake 命令简介
cmake 常用API详解
利用cmake搭建软件编译框架

主要的软件环境如下：

cmake版本：3.15
os:Ubuntu 18.04 64bit
Language:c/c++
cmake 命令行模式
大家可以从cmake官网下载cmake工具、查看相关的文档
Cmake官网

1 CMake 能做什么

CMake是一种管理源代码编译的工具，最初被设计成Makefile的生成器，随着应用越来越广泛，利用CMake可以生成Visual Studio 等IDE的工程文件以便于其进行编译。CMake主要在c/c++中使用，当然也可以利用它进行编译其他语言。

2 CMake编译模板整体框架

目录结构如下：

.
├── app  // 生成各种可执行文件
│   ├── CMakeLists.txt  // 添加各种子目录
│   └── cmake_test
│       ├── CMakeLists.txt  // 生成可执行文件 cmake_test
│       └── cmake_test.cpp
├── cmake_config  // cmake相关配置文件
│   ├── cm_commom.cmake  // 添加cmake一些公共的配置信息：比如说编译选项等
│   ├── cm_device_type.cmake // 设备型号配置文件
│   ├── cm_platform.cmake  // 平台相关的配置文件 比如说：硬件平台 软件平台等
│   └── cm_X86_64.cmake  // X86_64对应的配置文件
├── CMakeLists.txt  // 总体的cmake文件
├── components  // 组件类的配置文件 软件系统的各个组件
│   ├── CMakeLists.txt  // 本级目录的cmake文件
│   └── dpdk_fifo  // 无锁队列目录
│       ├── CMakeLists.txt // 生成 静态库或者动态库
│       ├── rte_atomic.h
│       ├── rte_ring.cpp
│       └── rte_ring.h
├── include  // 公共的头文件
├── lib  // Generate Dynamic Library or Static Library  in this directory ，all kinds of platform
│   └── X86_64  // X86_64 platform
│       ├── libdpdk_fifo.a
│       └── libdpdk_fifo.so
├── main_frame   // the main frame directory:include the main frame of the software system
│   ├── CMakeLists.txt
│   └── Event  // the event modle  handles all kinds of event,such as: read write timer signal etc..
│       └── CMakeLists.txt
├── out  // the out directory : the exe file and the dynamic library
│   └── cmake_test
│       ├── cmake_test
│       └── libdpdk_fifo.so
└── third_party  // the third party header file in this directory

3 项目使用

建立一个临时的编译目录在该目录中生成大量的中间文件

root@wan:/wan/fly_in_coding# mkdir build
root@wan:/wan/fly_in_coding# cd build/
root@wan:/wan/fly_in_coding/build# pwd
/wan/fly_in_coding/build
root@wan:/wan/fly_in_coding/build# pwd
/wan/fly_in_coding/build

生成Makefile

root@wan:/wan/fly_in_coding/build# cmake ../ -Dplatform=X86_64
-- The C compiler identification is GNU 7.4.0
-- The CXX compiler identification is GNU 7.4.0
-- Check for working C compiler: /usr/bin/cc
-- Check for working C compiler: /usr/bin/cc -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Detecting C compile features
-- Detecting C compile features - done
-- Check for working CXX compiler: /usr/bin/c++
-- Check for working CXX compiler: /usr/bin/c++ -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Configuring done
-- Generating done
-- Build files have been written to: /wan/fly_in_coding/build

执行编译

root@wan:/wan/fly_in_coding/build# make
Scanning dependencies of target dpdk_fifo
[ 25%] Building CXX object components/dpdk_fifo/CMakeFiles/dpdk_fifo.dir/rte_ring.cpp.o
[ 50%] Linking CXX shared library ../../../lib/X86_64/libdpdk_fifo.so
[ 50%] Built target dpdk_fifo
Scanning dependencies of target cmake_test
[ 75%] Building CXX object app/cmake_test/CMakeFiles/cmake_test.dir/cmake_test.cpp.o
[100%] Linking CXX executable cmake_test
[100%] Built target cmake_test
root@wan:/wan/fly_in_coding/build# ls
app  CMakeCache.txt  CMakeFiles  cmake_install.cmake  components  Makefile

进行安装将动态库和可执行文件复制到一个单独的目录下

root@wan:/wan/fly_in_coding/build# make install
[ 50%] Built target dpdk_fifo
[100%] Built target cmake_test
Install the project...
-- Install configuration: ""
-- Installing: /wan/fly_in_coding/out/cmake_test/cmake_test
-- Set runtime path of "/wan/fly_in_coding/out/cmake_test/cmake_test" to ""
-- Up-to-date: /wan/fly_in_coding/out/cmake_test
-- Installing: /wan/fly_in_coding/out/cmake_test/libdpdk_fifo.so

4 cmake文件清单及详解

4.1 顶级CMakeLists.txt

cmake_minimum_required(VERSION 3.5)
add_subdirectory(components)
add_subdirectory(app)

4.2 app CMakeLists.txt

cmake_minimum_required(VERSION 3.5)
add_subdirectory(cmake_test)

4.2.1 cmake_test中文件清单

CMakeLists.txt

#要求cmake版本最低3.5
cmake_minimum_required(VERSION 3.5)
include (../../cmake_config/cm_commom.cmake)
#根据设备类型选择不同的cmake配置文件
include (${PROJECT_ROOT_PATH}/cmake_config/cm_X86_64.cmake)
#设置当前工程名字
set(project_name cmake_test)
set (CMAKE_INSTALL_PREFIX ${PROJECT_ROOT_PATH}/out/${project_name})
#添加源文件目录
aux_source_directory(. DIR_SRCS)#当前模块生成可以行文件
add_executable(${project_name} ${DIR_SRCS})#添加当前模块需要的库
target_link_libraries(${project_name}  libdpdk_fifo.so )
install(TARGETS ${project_name} DESTINATION ${CMAKE_INSTALL_PREFIX})
install(DIRECTORY ${LIBRARY_OUTPUT_PATH}/ DESTINATION ${CMAKE_INSTALL_PREFIX} FILES_MATCHING PATTERN "*.so")

cmake_test.cpp

#include <stdio.h>
#include "rte_ring.h"
int main(void)
{struct rte_ring * r = NULL;r = rte_ring_create("test_ring",32,0);if(r != NULL){rte_ring_destory(r);}else{}printf("cmake_test \n");return 0;
}

4.3 cmake_config 文件详解

├── cmake_config // cmake相关配置文件
│ ├── cm_commom.cmake // 添加cmake一些公共的配置信息：比如说编译选项等
│ ├── cm_device_type.cmake // 设备型号配置文件
│ ├── cm_platform.cmake // 平台相关的配置文件比如说：硬件平台软件平台等
│ └── cm_X86_64.cmake // X86_64对应的配置文件

cm_commom.cmake

#添加 c++11 编译选项
add_compile_options(-std=c++11)#添加 debug -g 编译选项
add_compile_options(-g)add_compile_options(-fPIC)#把编译警告当做错误处理
#add_compile_options(-Werror) SET(PROJECT_ROOT_PATH "/wan/fly_in_coding")#添加公共的头文件
include_directories(#当前./ # 第三库文件   ${PROJECT_ROOT_PATH}/third_party/${PROJECT_ROOT_PATH}/app/cmake_test# 主框架头文件${PROJECT_ROOT_PATH}/main_frame/# 组件头文件${PROJECT_ROOT_PATH}/components/${PROJECT_ROOT_PATH}/components/dpdk_fifo/)
#SET(EXECUTABLE_OUTPUT_PATH ${PROJECT_ROOT_PATH}/out)

cm_device_type.cmake

#根据设备类型选择不同的cmake配置文件
if(${DEVICE} STREQUAL "MODLE1")add_definitions(-DMODLE1)
elseif(${DEVICE} STREQUAL "MODLE2")add_definitions(-DMODLE2)
elseif(${DEVICE} STREQUAL "MODLE3")add_definitions(-DMODLE3)
elseif(${DEVICE} STREQUAL "MODLE4")add_definitions(-DMODLE4)
else()
endif()

cm_platform.cmake

#根据设备类型选择不同的cmake配置文件
if(${platform} STREQUAL "X86_64")include (${PROJECT_ROOT_PATH}/cmake_config/cm_X86_64.cmake)
elseif(${platform} STREQUAL "NPNC2")include (${PROJECT_ROOT_PATH}/cmake_config/cm_X86_64.cmake)
else()include (${PROJECT_ROOT_PATH}/cmake_config/cm_X86_64.cmake)
endif()

cm_X86_64.cmake

add_definitions(-DX86_64)
SET(LIBRARY_OUTPUT_PATH  ${PROJECT_ROOT_PATH}/lib/X86_64)
link_directories(${PROJECT_ROOT_PATH}/lib/X86_64)

4.4 components 文件详解

├── components // 组件类的配置文件软件系统的各个组件
│ ├── CMakeLists.txt // 本级目录的cmake文件
CMakeLists.txt

#要求cmake版本最低3.5
cmake_minimum_required(VERSION 3.5)
# 添加子设备
add_subdirectory(dpdk_fifo)

│ └── dpdk_fifo // 无锁队列目录
│ ├── CMakeLists.txt // 生成静态库或者动态库
│ ├── rte_atomic.h
│ ├── rte_ring.cpp
│ └── rte_ring.h

4.4.1 dpdk_fifo中文件清单

CMakeLists.txt

#要求cmake版本最低3.5
cmake_minimum_required(VERSION 3.5)include (../../cmake_config/cm_commom.cmake)
include (${PROJECT_ROOT_PATH}/cmake_config/cm_platform.cmake)#添加源文件目录
aux_source_directory(. DIR_SRCS)#当前模块生成静态库
#add_library(dpdk_fifo STATIC ${DIR_SRCS})
# 当前模块生成动态库
add_library(dpdk_fifo SHARED ${DIR_SRCS})

5 结束语

上述模板可以应用一般的项目，可以根据自己的实际情况进行改动，文件清单中对每个函数的使用也进行了比较详细地解释，如果对于文中API 还有不清楚的可以去cmake官网进行查看。