CMake简介

cmake 是一个跨平台、开源的构建系统。它是一个集软件构建、测试、打包于一身的软件。它使用与平台和编译器独立的配置文件来对软件编译过程进行控制。

CMake是一种跨平台编译工具，比make更为高级，使用起来要方便得多。CMake主要是编写CMakeLists.txt文件，然后用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共享库（so(shared object)）

源码结构

.
├── build
├── CMakeLists.txt
├── include
│   └── b.h
└── src
    ├── b.c
    └── main.c

 

//b.h
#ifndef B_FILE_HEADER_INC
#define B_FIEL_HEADER_INC

#include<math.h>

double cal_sqrt(double value);

#endif

 

//b.c
#include "../include/b.h"

double cal_sqrt(double value)
{
    return sqrt(value);
}

 

//main.c
#include "../include/b.h"
#include <stdio.h>
int main(int argc, char** argv)
{
    double a = 49.0; 
    double b = 0.0;

    printf("input a:%f\n",a);
    b = cal_sqrt(a);
    printf("sqrt result:%f\n",b);
    return 0;
}

编写CMakeLists.txt

CMakeLists.txt文件，该文件放在和src，include的同级目录，实际方哪里都可以，只要里面编写的路径能够正确指向就好了

#1.cmake verson，指定cmake版本 
cmake_minimum_required(VERSION 3.2)

#2.project name，指定项目的名称，一般和项目的文件夹名称对应
PROJECT(test_sqrt)

#3.head file path，头文件目录
INCLUDE_DIRECTORIES(
include
)

#4.source directory，源文件目录
AUX_SOURCE_DIRECTORY(src DIR_SRCS)

#5.set environment variable，设置环境变量，编译用到的源文件全部都要放到这里，否则编译能够通过，但是执行的时候会出现各种问题，比如"symbol lookup error xxxxx , undefined symbol"
SET(TEST_MATH
${DIR_SRCS}
)

#6.add executable file，添加要编译的可执行文件
ADD_EXECUTABLE(${PROJECT_NAME} ${TEST_MATH})

#7.add link library，添加可执行文件所需要的库，比如我们用到了libm.so（命名规则：lib+name+.so），就添加该库的名称
TARGET_LINK_LIBRARIES(${PROJECT_NAME} m)

 

caoming@caoming:~/cm/test/test_sqrt$ mkdir build
caoming@caoming:~/cm/test/test_sqrt$ cd build/
caoming@caoming:~/cm/test/test_sqrt/build$ cmake ..
-- The C compiler identification is GNU 5.4.0
-- The CXX compiler identification is GNU 5.4.0
-- 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: /home/caoming/cm/test/test_sqrt/build
caoming@caoming:~/cm/test/test_sqrt/build$ make
Scanning dependencies of target test_sqrt
[ 33%] Building C object CMakeFiles/test_sqrt.dir/src/b.c.o
[ 66%] Building C object CMakeFiles/test_sqrt.dir/src/main.c.o
[100%] Linking C executable test_sqrt
[100%] Built target test_sqrt
caoming@caoming:~/cm/test/test_sqrt/build$ ./test_sqrt
input a:49.000000
sqrt result:7.000000