C++ vscode 开发环境搭建

笔记内容：

• C++ vscode 开发环境搭建准备
• 了解g++命令编译调试
• 掌握使用launch.json和tasks.json配置文件编译调试
• 了解使用cmake构建

git:
https://github.com/weichangk/hellocpp/tree/master/vscodecmakecpp

环境搭建准备

• 安装vscode
• 安装qt，通过Qt在线安装工具可以选择安装cmake（构建工具），mingw64（编译套件）
  Qt安装可以参考：https://blog.csdn.net/qq_39827640/article/details/127411878?spm=1001.2014.3001.5502
  Qt在线安装工具下载：https://download.qt.io/archive/online_installers/4.5/
• 配置cmake，mingw64环境变量
  • D:\Qt\Tools\CMake_64\bin
  • D:\Qt\Tools\mingw810_64\bin
• 安装插件
  • C/C++
  • C/C++ Themes
  • C/C++ Extension Pack
  • CMake

创建一个hello World

基于g++命令编译调试

参考：
https://www.runoob.com/w3cnote/cpp-header.html
https://www.runoob.com/w3cnote/gcc-parameter-detail.html
https://blog.csdn.net/Three_dog/article/details/103688043

C++的编译过程

1. 编译预处理：主要对包含的头文件（＃include ）和宏定义（＃define,#ifdef … ）还有注释等进行处理。
   g++ -E test.cpp -o test.ii
   g++ -E main.cpp -o main.ii

2. 编译：C++ 语法错误的检查，检查无误后，g++ 把代码翻译成汇编语言。
   g++ -S test.ii -o test.s
   g++ -S main.ii -o main.s

3. 汇编：g++ 汇编阶段：生成目标代码 *.o
   g++ -c test.s -o test.o
   g++ -c main.s -o main.o

4. g++ 链接阶段：生成可执行文件；Windows下生成.exe
   g++ main.o test.o -o multi.exe

带-g参数生成带调试信息的可执行文件并执行调试

1. g++编译单文件
   g++ -g main.cpp -o single
   .\single.exe

2. g++编译多个文件
   g++ -g main.cpp test.h test.cpp -o multi
   .\multi.exe

使用launch.json和tasks.json配置文件启动编译调试

参考：
https://code.visualstudio.com/docs/cpp/config-mingw

.vscode文件夹中文件作用注释:

• tasks.json (构建指令)
• launch.json (设置调试器)
• c_cpp_properties.json (编译器路径和智能感知设置)
• settings.json

1. 生成默认的tasks.json文件
   VSCode中Task的使用参考：https://blog.csdn.net/qq_53653262/article/details/120859147
   选择一个cpp文件，打开“终端”菜单“配置默认生成任务”选择“C/C++: g++.exe 生成活动文件”，文件如下：

   {"version": "2.0.0","tasks": [{"type": "cppbuild","label": "C/C++: g++.exe 生成活动文件","command": "D:\\Qt\\Tools\\mingw810_64\\bin\\g++.exe","args": ["-fdiagnostics-color=always","-g","${file}","-o","${fileDirname}\\${fileBasenameNoExtension}.exe"],"options": {"cwd": "${fileDirname}"},"problemMatcher": ["$gcc"],"group": {"kind": "build","isDefault": true},"detail": "编译器: D:\\Qt\\Tools\\mingw810_64\\bin\\g++.exe"}]
   }
   

2. 生成默认的launch.json文件
   更多内容可参考：https://blog.csdn.net/qq_16587307/article/details/106593867
   点击调试按钮，创建launch.json文件，选择对应的项目或工作区，选择g++.exe生成和调试活动文件，如果没有g++(GDB/LLDB)选项可以将c++插件退回到1.8.4（右键插件安装另一个版本），文件如下：

   {// 使用 IntelliSense 了解相关属性。 // 悬停以查看现有属性的描述。// 欲了解更多信息，请访问: https://go.microsoft.com/fwlink/?linkid=830387"version": "0.2.0","configurations": [{"name": "(gdb) 启动","type": "cppdbg","request": "launch","program": "输入程序名称，例如 ${workspaceFolder}/a.exe","args": [],"stopAtEntry": false,"cwd": "${fileDirname}","environment": [],"externalConsole": false,"MIMode": "gdb","miDebuggerPath": "/path/to/gdb","setupCommands": [{"description": "为 gdb 启用整齐打印","text": "-enable-pretty-printing","ignoreFailures": true},{"description": "将反汇编风格设置为 Intel","text": "-gdb-set disassembly-flavor intel","ignoreFailures": true}]}]
   }
   

3. 修改tasks.json launch.json文件关键参数
   详细参数说明参考：
   https://code.visualstudio.com/docs/cpp/config-mingw

• tasks.json
  • label
  • command
  • args
  • options cwd
• launch.json
  • program
  • cwd
  • miDebuggerPath
  • preLaunchTask

4. 修改后的文件

   //tasks.json
   {"version": "2.0.0","tasks": [{"type": "cppbuild","label": "C/C++: g++.exe vscodecmakecpp","command": "D:\\Qt\\Tools\\mingw810_64\\bin\\g++.exe","args": ["-fdiagnostics-color=always","-g","main.cpp","test.cpp","-o","${workspaceFolder}\\src\\${workspaceFolderBasename}.exe"],"options": {"cwd": "${workspaceFolder}\\src"},"problemMatcher": ["$gcc"],"group": {"kind": "build","isDefault": true},"detail": "编译器: D:\\Qt\\Tools\\mingw810_64\\bin\\g++.exe"}]
   }//launch.json
   {"version": "0.2.0","configurations": [{"name": "(gdb) 启动","type": "cppdbg","request": "launch","program": "${workspaceFolder}\\src\\${workspaceFolderBasename}.exe","args": [],"stopAtEntry": false,"cwd": "${workspaceFolder}\\src","environment": [],"externalConsole": false,"MIMode": "gdb","miDebuggerPath": "D:\\Qt\\Tools\\mingw810_64\\bin\\gdb.exe","setupCommands": [{"description": "为 gdb 启用整齐打印","text": "-enable-pretty-printing","ignoreFailures": true},{"description": "将反汇编风格设置为 Intel","text": "-gdb-set disassembly-flavor intel","ignoreFailures": true}],"preLaunchTask": "C/C++: g++.exe vscodecmakecpp"//关联tasks.json文件}]
   }
   

5. tasks.json launch.json之间的关系

• tasks.json：g++构建指令，可以直接在“终端”选择“运行任务”中选择构建任务执行编译。
• launch.json：gdb调试器参数，附加tasks.json可以通过vscode执行编译调试并输出调试信息。

6. c_cpp_properties.json 配置文件作用是：代码提示、代码跳转等
   参考：
   https://blog.csdn.net/fdfdsds/article/details/102248876
   https://blog.csdn.net/weixin_40694527/article/details/84251461

基于cmake编译调试

关于cmake的更多内容参考（后续写关于cmake的学习笔记）：
https://cmake.org/documentation/
https://github.com/microsoft/vscode-cmake-tools/blob/main/docs/README.md

添加CMakeLists.txt文件

cmake_minimum_required(VERSION 3.5)
project(vscodecmakecpp LANGUAGES CXX)set(CMAKE_INCLUDE_CURRENT_DIR ON)
set(CMAKE_CXX_STANDARD 11)
set(CMAKE_CXX_STANDARD_REQUIRED ON)
set(CMAKE_PREFIX_PATH "d:/Qt/5.15.2/mingw81_64")aux_source_directory(./src SRCS)add_executable(${PROJECT_NAME}${SRCS}
)

CMake:select a kit（如果无选项可以先确保配置环境变量后使用Scan for kits搜索，或重启vscode再搜索再选择）
CMake指令：F7编译、Ctrl + F5调试

使用launch.json结合CMakeLists.txt配置文件进行调试，直接使用vscode F5启动调试
通过修改launch.json文件"program": "${command:cmake.launchTargetPath}“参数使得launch.json使用CMakeLists.txt构建输出文件作为启动目标路径。
删掉"preLaunchTask”: “C/C++: g++.exe vscodecmakecpp” 关联了CMakeLists.txt就不需要关联tasks.json文件了。