CMake语法—调用顺序（calling sequence）

目录

• CMake语法—调用顺序（calling sequence）
  • 1 示例代码
  • 2 代码结构
  • 3 代码内容
  • 4 运行结果
  • 5 总结

CMake语法—调用顺序（calling sequence）

1 示例代码

2 代码结构

• learn_cmake：为根目录

• CMakeLists.txt：CMake主脚本

• cmake_config.bat：执行CMake配置过程的脚本（双击直接运行）

  @echo off
  set currentDir=%~dp0
  set buildDir=%currentDir%
  set cmakeOutputDir=%currentDir%\build
  cmake -S %buildDir% -B %cmakeOutputDir% -G"Visual Studio 16 2019" -T v140 -A x64
  pause

• src：工程源文件目录

• main.cpp：源文件

• include：工程头文件目录

• libs：工程业务模块库

• tools：工程业务工具库

3 代码内容

1. 工程主CMakeLists.txt，即最外层的CMake脚本，也是CMake配置的入口

   cmake_minimum_required(VERSION 3.18)
    
   # 设置工程名称
   set(PROJECT_NAME KAIZEN)
    
   # 设置工程版本号
   set(PROJECT_VERSION "1.0.0.10" CACHE STRING "默认版本号")
    
   # 工程定义
   project(${PROJECT_NAME}
       LANGUAGES CXX C
       VERSION ${PROJECT_VERSION}
   )
    
   # 打印开始日志
   message(STATUS "########## BEGIN_TEST")
    
   include(CMakePrintHelpers)
    
   set(prefix "call_stack_prefix")
    
   cmake_print_variables(prefix PROJECT_NAME)
    
   ## 一般会先编译业务模块库
   add_subdirectory(libs)
    
   ## 再编译业务工具库
   add_subdirectory(tools)
    
   # 打印结束日志
   message(STATUS "########## END_TEST\n")

2. libs目录下的主CMakeLists.txt，即libs目录下最外层的CMake脚本，也是CMake配置在libs目录的入口

   cmake_minimum_required(VERSION  3.15)
    
   set(DIR_NAME libs)
    
   cmake_print_variables(prefix DIR_NAME)
    
   add_subdirectory(moduleA)
   add_subdirectory(moduleB)
   add_subdirectory(moduleC)

   • libs下moduleA业务模块目录的CMakeLists.txt

     cmake_minimum_required(VERSION  3.15)
      
     set(TARGET_NAME moduleA)
      
     cmake_print_variables(prefix TARGET_NAME)

   • libs下moduleB业务模块目录的CMakeLists.txt

     cmake_minimum_required(VERSION  3.15)
      
     set(TARGET_NAME moduleB)
      
     cmake_print_variables(prefix TARGET_NAME)

   • libs下moduleC业务模块目录的CMakeLists.txt

     cmake_minimum_required(VERSION  3.15)
      
     set(TARGET_NAME moduleC)
      
     cmake_print_variables(prefix TARGET_NAME)

3. tools目录下的主CMakeLists.txt，即tools目录下最外层的CMake脚本，也是CMake配置在tools目录的入口

   cmake_minimum_required(VERSION  3.15)
    
   set(DIR_NAME tools)
    
   cmake_print_variables(prefix DIR_NAME)
    
   add_subdirectory(toolA)
    
   add_subdirectory(toolC)
    
   add_subdirectory(toolB)

   • tools下toolA工具目录下的CMakeLists.txt

     cmake_minimum_required(VERSION  3.15)
      
     set(TARGET_NAME toolA)
      
     cmake_print_variables(prefix TARGET_NAME)

   • tools下toolB工具目录下的CMakeLists.txt

     cmake_minimum_required(VERSION  3.15)
      
     set(TARGET_NAME toolB)
      
     cmake_print_variables(prefix TARGET_NAME)

   • tools下toolC工具目录下的CMakeLists.txt

     cmake_minimum_required(VERSION  3.15)
      
     set(TARGET_NAME toolC)
      
     cmake_print_variables(prefix TARGET_NAME)

4. main.cpp

   int main()
   {
       return 0;
   }

4 运行结果

执行顺序运行结果如下：

-- Selecting Windows SDK version 10.0.18362.0 to target Windows 10.0.17763.
-- The CXX compiler identification is MSVC 19.0.24245.0
-- The C compiler identification is MSVC 19.0.24245.0
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: C:/Program Files (x86)/Microsoft Visual Studio 14.0/VC/bin/amd64/cl.exe - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working C compiler: C:/Program Files (x86)/Microsoft Visual Studio 14.0/VC/bin/amd64/cl.exe - skipped
-- Detecting C compile features
-- Detecting C compile features - done
-- ########## BEGIN_TEST
-- prefix="call_stack_prefix" ; PROJECT_NAME="KAIZEN"
-- prefix="call_stack_prefix" ; DIR_NAME="libs"
-- prefix="call_stack_prefix" ; TARGET_NAME="moduleA"
-- prefix="call_stack_prefix" ; TARGET_NAME="moduleB"
-- prefix="call_stack_prefix" ; TARGET_NAME="moduleC"
-- prefix="call_stack_prefix" ; DIR_NAME="tools"
-- prefix="call_stack_prefix" ; TARGET_NAME="toolA"
-- prefix="call_stack_prefix" ; TARGET_NAME="toolC"
-- prefix="call_stack_prefix" ; TARGET_NAME="toolB"
-- ########## END_TEST
 
-- Configuring done
-- Generating done
-- Build files have been written to: F:/learn_cmake/build
请按任意键继续. . .

5 总结

CMake配置项目时，会从主CMakeLists.txt开始配置（比如此示例中最外层的CMakeLists.txt）

接下来顺序，会严格按主CMakeLists.txt的具体写法（比如此示例中先添加libs子目录，后添加tools子目录，运行结果打印也是如此）

遇见add_subdirectory，就先对此子目录先执行配置（比如此示例中在子目录tools中，先添加toolC，后添加toolB，运行结果打印也是如此）

遵循此规律，以此类推，直至到配置完成。