CMake 实例学习（0）开始

1：CMake概述
   说简单点，CMake 就是为我们生成 makefile 文件的，你是否在为撰写makefile而头疼呢，那就试试CMake吧，我也是一边学习，一边做一些笔记，难免会有一些理解错误的地方，还望各位看客及时指出，Thanks.

2：从“Hello world”开始

[onezeroone@ ex-1]$ pwd
/home/onezeroone/work/backup/cmake/ex-1
[onezeroone@ ex-1]$ ls
hello.c

#include <stdio.h>
int
main(void)
{
        printf("Hello world\n");

        return 0;
}

3: 撰写CMakeLists.txt

[onezeroone@ ex-1]$ ls
CMakeLists.txt  hello.c
[onezeroone@ ex-1]$ cat CMakeLists.txt
PROJECT(HELLO)
ADD_EXECUTABLE(hello hello.c)

CMakeLists.txt内容够简单吧，当然相对makefile来说。
PROJECT语法：
PROJECT(projectname [CXX] [C] [JAVA])
用于指定工程名字，[]为可选内容，默认表示支持所有语言。

ADD_EXECUTABLE(hello hello.c)
定义工程生产的可执行文件名为hello， 源文件为hello.c

4：执行cmake .

[onezeroone@ ex-1]$ cmake .
-- The C compiler identification is GNU
-- The CXX compiler identification is GNU
-- Check for working C compiler: /usr/bin/gcc
-- Check for working C compiler: /usr/bin/gcc -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - 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
-- Configuring done
-- Generating done
-- Build files have been written to: /home/onezeroone/work/backup/cmake/ex-1

我们可以看到，cmake过程中为我们打印出了很多信息，现在我们不需要关心这些，没有ERROR就OK

[onezeroone@ ex-1]$ ls
CMakeCache.txt  CMakeFiles  cmake_install.cmake  CMakeLists.txt  hello.c  Makefile

我们可以看到cmake为我们生成了很多文件，我们只关心我们的Makefile，现在我们可以make了。

5.make

[onezeroone@ ex-1]$ make
Scanning dependencies of target hello
[100%] Building C object CMakeFiles/hello.dir/hello.c.o
Linking C executable hello
[100%] Built target hello

我们可以看到成功生成hello文件，至此我们可以我们的hello world了

[onezeroone@ ex-1]$ ls
CMakeCache.txt  CMakeFiles  cmake_install.cmake  CMakeLists.txt  hello  hello.c  Makefile
[onezeroone@ ex-1]$ ./hello
Hello world

当然，这只是最简单的cmake在Linux下的应用，后面我们继续学习我们的cmake.