CMake

CMake 官方教程

一、CMake介绍

CMake 是个一个开源的跨平台自动化建构系统，用来管理软件建置的程序，并不依赖于某特定编译器，并可支持多层目录、多个应用程序与多个函数库。
CMake 通过使用简单的配置文件 CMakeLists.txt，自动生成不同平台的构建文件（如 Makefile、Ninja 构建文件、Visual Studio 工程文件等），简化了项目的编译和构建过程。
CMake 本身不是构建工具，而是生成构建系统的工具，它生成的构建系统可以使用不同的编译器和工具链。

从创建项目到编译和运行的整个过程包含以下步骤：

1. 创建 CMakeLists.txt 文件：定义项目、库、可执行文件和测试。
2. 编写源代码和测试：编写代码和测试文件。
3. 创建构建目录：保持源代码目录整洁。
4. 配置项目：生成构建系统文件。
5. 编译项目：生成目标文件。
6. 运行可执行文件：执行程序。
7. 运行测试：验证功能正确性。
8. 使用自定义命令和目标：执行额外操作。
9. 跨平台和交叉编译：支持不同平台和架构。

二、实战举例

具体命令用法查看官方文档

假设项目结构如下：

.
├── CMakeLists.txt
├── MathFunctions
│   ├── CMakeLists.txt
│   ├── MathFunctions.cxx
│   ├── MathFunctions.h
│   ├── mysqrt.cxx
│   └── mysqrt.h
├── TutorialConfig.h.in
└── tutorial.cxx

根目录下的 CMakeLists.txt 文件：

cmake_minimum_required(VERSION 3.10)

# set the project name and version
project(Tutorial VERSION 1.0)

# Replace the following code by:
# * Creating an interface library called tutorial_compiler_flags
#   Hint: use add_library() with the INTERFACE signature
# * Add compiler feature cxx_std_11 to tutorial_compiler_flags
#   Hint: Use target_compile_features()

# specify the C++ standard
add_library(tutorial_compiler_flags INTERFACE)
target_compile_features(tutorial_compiler_flags INTERFACE cxx_std_11)

# configure a header file to pass some of the CMake settings
# to the source code
configure_file(TutorialConfig.h.in TutorialConfig.h)

# add the MathFunctions library
add_subdirectory(MathFunctions)
list(APPEND "${PROJECT_SOURCE_DIR}/MathFunctions")

# add the executable
add_executable(Tutorial tutorial.cxx)

# Link Tutorial to tutorial_compiler_flags
target_link_libraries(Tutorial PUBLIC MathFunctions tutorial_compiler_flags)

# add the binary tree to the search path for include files
# so that we will find TutorialConfig.h
target_include_directories(Tutorial PUBLIC
                           "${PROJECT_BINARY_DIR}"
                           )

MathFunctions 目录下的 CMakeLists.txt 文件：

add_library(MathFunctions MathFunctions.cxx)

# State that anybody linking to MathFunctions needs to include the
# current source directory, while MathFunctions itself doesn't.
# Hint: Use target_include_directories with the INTERFACE keyword
target_include_directories(MathFunctions
                           INTERFACE ${CMAKE_CURRENT_SOURCE_DIR}
                           )

# should we use our own math functions
option(USE_MYMATH "Use tutorial provided math implementation" ON)
if (USE_MYMATH)
  target_compile_definitions(MathFunctions PRIVATE "USE_MYMATH")

  # library that just does sqrt
  add_library(SqrtLibrary STATIC
              mysqrt.cxx
              )

  # Link SqrtLibrary to tutorial_compiler_flags
  target_link_libraries(SqrtLibrary PUBLIC tutorial_compiler_flags)

  target_link_libraries(MathFunctions PRIVATE SqrtLibrary)
endif()

# Link MathFunctions to tutorial_compiler_flags
target_link_libraries(MathFunctions PUBLIC tutorial_compiler_flags)

编译步骤：

/home/bb/cmake-4.0.0-tutorial-source/Step2# mkdir build
/home/bb/cmake-4.0.0-tutorial-source/Step2# cd build
/home/bb/cmake-4.0.0-tutorial-source/Step2# cmake ..
/home/bb/cmake-4.0.0-tutorial-source/Step2# cmake --build .
/home/bb/cmake-4.0.0-tutorial-source/Step2# ./Tutorial 25 // 运行