用CMake 替换 Makefile

原文：https://blog.csdn.net/love131452098/article/details/116241448

CMake实质上是用于生成Makefile的工具，现在越来越多开源的项目, 在项目的编译框架上使用CMake替换Makefile. CMake 相对于Makefile规则更加简单，重要的是CMake官方网站提供了较为友好的指南.

CMake 官方学习资料指引

CMake 入门指南(英文版)

CMake tutorial CMake 教程

CMake 学习资料集合

学习资料集合

CMake 替换Makefile CMake 替换Makefile

接下来会以以下三个点来展示CMake 替换Makefile.

1. 编译目标文件，直接生成可执行程序
2. .a 或者 .so 库文件编译生成
3. 链接库文件

1. 直接生成可执行程序

打开Linux下的终端，创建如下目录和文件.

➜  cmake_example tree
.
├── build
└── src
    ├── CMakeLists.txt
    └── hello.c

-> hello.c, 只是简单的一个main函数，然后打印字符串"Hello"

#include <stdio.h>

int main(int argc, char **argv){
    printf("Hello \r\n");
    return 0;                                                   
}

-> src/CMakeLists.txt, 只是设置了项目名称(最终可执行程序的名称)，和直接直接编译可执行程序

# set the project name and version
cmake_minimum_required(VERSION 3.10)

#set the project name
project(Hello VERSION 2.0)


#add the executable
add_executable(Hello hello.c)

在完成目录和文件的创建后，我们通过cmake指令进行Makefile的生成和代码工程编译.

在工程的顶层目录，执行cd指令进入build目录，然后运行cmake指令+源码所在目录(也就是CMakeLists.txt的所在目录). 具体过程如下，cmake命令运行成功后在build目录生成了Makefile文件和其它相关文件.

➜  cmake_example cd build 
➜  build ls
➜  build cmake ../src/
-- The C compiler identification is GNU 7.5.0
-- The CXX compiler identification is GNU 7.5.0
-- 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: /home/tracy/Work_Space/Apollo/base_tech/apollo_cmake/basic_start/cmake_example/build
➜  build ls
CMakeCache.txt  CMakeFiles  cmake_install.cmake  Makefile

在生成Makefile文件后，可以直接在build目录下执行: make或者cmake指令，具体如下,

➜  build cmake --build .
Scanning dependencies of target Hello
[ 50%] Building C object CMakeFiles/Hello.dir/hello.c.o
[100%] Linking C executable Hello
[100%] Built target Hello
➜  build make
[100%] Built target Hello

最后会在build目录下生成，可执行程序Hello.

➜  build make
[100%] Built target Hello
➜  build ls
CMakeCache.txt  cmake_install.cmake  Makefile
CMakeFiles      Hello
➜  build ./Hello 
Hello 

2. .so或者 .a 库文件编译生成

打开Linux下的终端，创建如下目录和文件

➜  cmake_example tree
.
├── build
└── src
    ├── CMakeLists.txt
    ├── hello.c
    └── hello.h

hello.c, 库的源文件

#include <stdio.h>

int say_hello(void){
    printf("Hello \r\n");
    return 0;
}

hello.h

#ifndef __HELLO__
#define __HELLO__

int say_hello(void);

#endif

CMakeLists.txt

cmake_minimum_required(VERSION 3.10)

#set the project name
project(Hello VERSION 2.0)

# SHARED 为动态库， STATIC为静态库
add_library(hello SHARED 
            hello.c) 

 target_include_directories(hello PUBLIC
                           "${PROJECT_BINARY_DIR}"
                           )
                           
在以上文件完成创建后，在工程的顶层目录，执行cd指令进入build目录，然后运行cmake指令+源码所在目录(也就是CMakeLists.txt的所在目录). 具体过程如下，cmake命令运行成功后在build目录生成了Makefile文件和其它相关文件
```bash
➜  build cmake ../src
-- The C compiler identification is GNU 7.5.0
-- The CXX compiler identification is GNU 7.5.0
-- 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: /home/tracy/Work_Space/Apollo/base_tech/apollo_cmake/basic_start/cmake_example/build
➜  build make
Scanning dependencies of target hello
[ 50%] Building C object CMakeFiles/hello.dir/hello.c.o
[100%] Linking C shared library libhello.so
[100%] Built target hello

最后会在build目录下生成，库文件libhello.so

3. 链接库文件

打开Linux下的终端，创建如下目录和文件

➜  cmake_example tree
.
├── build
└── src
    ├── CMakeLists.txt
    ├── hello.c
    ├── hello.h
    └── main.c

main.c, 调用libhello.so 中的say_hello()
main.c, 调用libhello.so 中的say_hello()

#include <stdio.h>
#include "hello.h"

int main(int argc, char **argv){
    say_hello();
    return 0;
}

hello.c, 库的源文件

#include <stdio.h>

int say_hello(void){
    printf("Hello \r\n");
    return 0;
}

hello.h

#ifndef __HELLO__
#define __HELLO__

int say_hello(void);

#endif

CMakeLists.txt

cmake_minimum_required(VERSION 3.10)

#set the project name
project(Hello VERSION 2.0)

# add the executable
add_executable(Hello main.c)

add_library(hello SHARED 
            hello.c)

target_link_libraries(Hello PUBLIC hello)

target_include_directories(hello PUBLIC
                           "${PROJECT_BINARY_DIR}"
                           )

在以上文件完成创建后，在工程的顶层目录，执行cd指令进入build目录，然后运行cmake指令+源码所在目录(也就是CMakeLists.txt的所在目录). 具体过程如下，cmake命令运行成功后在build目录生成了Makefile文件和其它相关文件.

最后在build目录，生成了可执行程序Hello.

refs：

https://blog.csdn.net/love131452098/article/details/116241448

https://www.cnblogs.com/silence-cho/p/16212503.html