# cmakeTest

**Repository Path**: longlongint/cmake-test

## Basic Information

- **Project Name**: cmakeTest
- **Description**: No description available
- **Primary Language**: Unknown
- **License**: Not specified
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 0
- **Created**: 2021-08-15
- **Last Updated**: 2021-08-22

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

CMake-Demo
=====

[CMake 入门实战](https://hahack.com/codes/cmake) 的源代码。

copy from [github](https://github.com/wzpan/cmake-demo)

> 个人理解，cmake 就是对 makefile 语句的一些封装

# 使用

## windows

> 假设已经安装 MinGW

```sh
mkdir build && cd build
cmake ..\Demo4 -G "MinGW Makefiles"
mingw32-make
```

# Demo 解释

## demo 1

### [cmake_minimum_required][]

指定cmake的最低版本

```cmake
# 版本最低要求2.8
cmake_minimum_required (VERSION 2.8...3.21)
```

### [project][]

设置工程名

```cmake
# 设置工程名叫 Demo1
project (Demo1)
```

### [add_executable][]

使用指定源文件 `创建` 一个可执行文件

```cmake
#用 main.cc 创建可执行文件 a.exe
add_executable(a.exe main.cc)
```

---

## demo 2

### [aux_source_directory][]

收集指定目录中的所有源文件并存储到列表 variable
<br>疑问：哪些扩展名算源文件

```cmake
# 查找当前目录下的所有源文件，并将名称保存到 DIR_SRCS 变量
aux_source_directory(. DIR_SRCS)

# 用 DIR_SRCS 保存的名字 创建 可执行文件
add_executable(a.exe ${DIR_SRCS})
```

---

## demo 3

### [add_subdirectory][]

添加一个需要被构建的子目录

```cmake
# math 目录需要先被构建
add_subdirectory(math)
```

### [target_link_libraries][]

给要链接的目标指定 `库或编译选项`

```cmake
# 编译 a.exe 的时候需要链接 MathFunctions 库
target_link_libraries(a.exe MathFunctions)
```

### [add_library][]

使用指定源文件 `创建` 一个库

```cmake
# 创建 MathFunctions 动态库, 默认静态库
add_library (MathFunctions SHARED MathFunctions.cc MathFunctions.h )
```

---

## demo 4

CMake 允许为项目增加选项，从而可根据需求选择合适的编译方案

### [configure_file][]

```cmake
# 加入一个配置头文件，会将 config.h.in 复制到 config.h
# #cmakedefine VAR ... 被复制为 #define VAR ...
configure_file (
  "${PROJECT_SOURCE_DIR}/config.h.in"
  "${PROJECT_BINARY_DIR}/config.h"
  )
```

### [option][]

给用户提供一个选项

```cmake
# 是否使用自己的 MathFunctions 库，默认开
option (USE_MYMATH
       "Use provided math implementation" ON)
```

### [set][]

### [include_directories][]

增加一个头文件搜索路径

```cmake
# 是否加入 MathFunctions 库
if (USE_MYMATH)
  include_directories ("${PROJECT_SOURCE_DIR}/math")
  add_subdirectory (math)  
  set (EXTRA_LIBS ${EXTRA_LIBS} MathFunctions)
endif (USE_MYMATH)
```

生成命令

```sh
cmake ../Demo4 -DUSE_MYMATH=OFF
```

当 CMakeList.txt 与 config.h.in 都含有 变量 USE_MYMATH 的定义

| CMakeList.txt | config.h.in | config.h |
|--|--|--|
OFF|ON/OFF|#undef
ON|ON/OFF|#defined

所以，[configure_file][] 是为了让普通文件，也能使用CMake中的变量

---

## demo 5

### [install][]

指定安装规则

```cmake
# 指定二进制安装路径
install (TARGETS Demo DESTINATION bin)
# 头文件安装路径
install (FILES "${PROJECT_BINARY_DIR}/config.h" DESTINATION include)
# 指定 MathFunctions 库的安装路径
install (TARGETS ${PROJECT_NAME}_MathFunctions DESTINATION lib)
# 库头文件安装路径
install (FILES MathFunctions.h DESTINATION include)
```

用法：

```sh
mkdir build && cd build
cmake ../Demo5 -DCMAKE_INSTALL_PREFIX=`pwd`/install
make install -j16
```

### [enable_testing()][]

为当前目录和子目录启用测试
* [add_test][]
  + 添加测试项
* [set_tests_properties][]
  + 设置测试结果

---

## demo 6

### [include][]

从文件或模块加载 CMake 代码

### [CheckFunctionExists][]

链接时检查函数是否存在

```cmake
# 检查系统是否支持 pow 函数
include (${CMAKE_ROOT}/Modules/CheckFunctionExists.cmake)
check_function_exists (pow HAVE_POW)
```

---

## demo 7

设置版本信息
* 1、cmake 中加入：
  

```cmake
  set (Demo_VERSION_MAJOR 1)
  set (Demo_VERSION_MINOR 0)
  ```

* 2、config.h.in 中
  

```h
  #define Demo_VERSION_MAJOR @Demo_VERSION_MAJOR@
  #define Demo_VERSION_MINOR @Demo_VERSION_MINOR@
  ```

---

## demo 8

构建 cpack 包

```cmake
# 构建一个 CPack 安装包
include (InstallRequiredSystemLibraries)
set (CPACK_RESOURCE_FILE_LICENSE "${CMAKE_CURRENT_SOURCE_DIR}/License.txt")
include (CPack)
```

用法：

```sh
mkdir build && cd build
cmake ../Demo5 -DCMAKE_INSTALL_PREFIX=`pwd`/install
make install -j16
# 生成二进制安装包
cpack -C CPackConfig.cmake
# 生成源码安装包
cpack -C CPackSourceConfig.cmake
# 安装
sh Demo8-1.0.1-Linux.sh
```

[cmake_minimum_required]:https://cmake.org/cmake/help/latest/command/cmake_minimum_required.html
[project]:https://cmake.org/cmake/help/latest/command/project.html
[add_executable]:https://cmake.org/cmake/help/latest/command/add_executable.html
[aux_source_directory]:https://cmake.org/cmake/help/latest/command/aux_source_directory.html
[add_subdirectory]:https://cmake.org/cmake/help/latest/command/add_subdirectory.html
[target_link_libraries]:https://cmake.org/cmake/help/latest/command/target_link_libraries.html
[add_library]:https://cmake.org/cmake/help/latest/command/add_library.html
[configure_file]:https://cmake.org/cmake/help/latest/command/configure_file.html
[option]:https://cmake.org/cmake/help/latest/command/option.html
[include_directories]:https://cmake.org/cmake/help/latest/command/include_directories.html
[set]:https://cmake.org/cmake/help/latest/command/set.html
[install]:https://cmake.org/cmake/help/latest/command/install.html
[enable_testing()]:https://cmake.org/cmake/help/latest/command/enable_testing.html
[add_test]:https://cmake.org/cmake/help/latest/command/add_test.html
[set_tests_properties]:https://cmake.org/cmake/help/latest/command/set_tests_properties.html
[CheckFunctionExists]:https://cmake.org/cmake/help/latest/module/CheckFunctionExists.html
[include]:https://cmake.org/cmake/help/latest/command/include.html