vscode C++ 分文件、文件夹编译配置与错误解决

问题

如下图文件夹

> include: *.h文件
> out: 编译后的输出文件夹
> source：*.cpp文件

先看看我们的几个文件夹里有什么文件，还有文件里有什么内容。

include

• add.h
  • 这里就是add()函数的声明
  • 还需要要加上 int test_add();这个声明
    

source

• main.cpp
  • 简单的一个程序入口
    
• add.cpp
  • 这里是我们主要的程序部分，定义了几个add()函数。还有test_add()函数
  • 还需要#include “add.h”
    

out

• 现在还没有编译过，所以为空

那我们要怎样配置vscode里的一些环境呢？

配置过程遇到的问题与解决

遇到的问题1

identifier "test_add" is undefinedC/C++(20)

说白了，就是test_add这个标识符不能识别（没有定义），可我们从上面的文件里看到了，该函数都是有的。再往下看，我们一个一个来解决。

解决步骤

1. ctrl + shift + p

然后选择如下箭头所指示

出现如下，选择Debug Anyway

完成这一步了，我们可以参文件下面，会有一个.vscode的文件夹，还有两个.json的文件。

2. 配置json文件

修改task.json文件

默认的如下，主要要修改三个地方

1. 添加 -I，及-I对应的文件夹 (include)
2. 修改 -o，及-o对文件夹 (out)
3. 修改-g，及-g对应的文件(source)

{
    "tasks": [
        {
            "type": "cppbuild",
            "label": "C/C++: g++ build active file",
            "command": "/usr/bin/g++",
            "args": [
                "-g",
                "${file}",
                "-o",
                "${fileDirname}/${fileBasenameNoExtension}"
            ],
            "options": {
                "cwd": "${fileDirname}"
            },
            "problemMatcher": [
                "$gcc"
            ],
            "group": {
                "kind": "build",
                "isDefault": true
            },
            "detail": "Task generated by Debugger."
        }
    ],
    "version": "2.0.0"
}

修改如下

{
    "tasks": [
        {
            "type": "cppbuild",
            "label": "C/C++: g++ build active file",
            "command": "/usr/bin/g++",
            "args": [
                "-g",
                "${workspaceFolder}/source/*.cpp", //all cpp from source
                "-I", //include
                "${workspaceFolder}/include", //include path
                "-o",
                "${workspaceFolder}/out/${fileBasenameNoExtension}" //out path
            ],
            "options": {
                "cwd": "${fileDirname}"
            },
            "problemMatcher": [
                "$gcc"
            ],
            "group": {
                "kind": "build",
                "isDefault": true
            },
            "detail": "Task generated by Debugger."
        }
    ],
    "version": "2.0.0"
}

修改launch.json

默认的launch.json如下，
只需要修改2版主即可

1. “program” 后的属性，修改成与tasks.json -o 后的属性一样
2. “cwd”: 属性修改为 “${workspaceFolder}/out”

{
    // Use IntelliSense to learn about possible attributes.
    // Hover to view descriptions of existing attributes.
    // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
    "version": "0.2.0",
    "configurations": [
        {
            "name": "g++ - Build and debug active file",
            "type": "cppdbg",
            "request": "launch",
            "program": "${fileDirname}/${fileBasenameNoExtension}",
            "args": [],
            "stopAtEntry": false,
            "cwd": "${fileDirname}",
            "environment": [],
            "externalConsole": false,
            "MIMode": "gdb",
            "setupCommands": [
                {
                    "description": "Enable pretty-printing for gdb",
                    "text": "-enable-pretty-printing",
                    "ignoreFailures": true
                }
            ],
            "preLaunchTask": "C/C++: g++ build active file",
            "miDebuggerPath": "/usr/bin/gdb"
        }
    ]
}

修改如下，都已经加注释了

{
    // Use IntelliSense to learn about possible attributes.
    // Hover to view descriptions of existing attributes.
    // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
    "version": "0.2.0",
    "configurations": [
        {
            "name": "g++ - Build and debug active file",
            "type": "cppdbg",
            "request": "launch",
            "program": "${workspaceFolder}/out/${fileBasenameNoExtension}", //program output name, same as tasks.json -o path
            "args": [],
            "stopAtEntry": false,
            "cwd": "${workspaceFolder}/out", //out here is the folder named out
            "environment": [],
            "externalConsole": false,
            "MIMode": "gdb",
            "setupCommands": [
                {
                    "description": "Enable pretty-printing for gdb",
                    "text": "-enable-pretty-printing",
                    "ignoreFailures": true
                }
            ],
            "preLaunchTask": "C/C++: g++ build active file",
            "miDebuggerPath": "/usr/bin/gdb"
        }
    ]
}

保存以上文件后，已经不报错了

• F5: 调试程序
• CTRL+F5：运行程序
• ctrl + shift + B (build)

可能遇到的错误

1. collect2: error: ld returned 1 exit status

/usr/bin/g++ -g /mnt/d/tmp/c++/source/main.cpp -I /mnt/d/tmp/c++/include -o /mnt/d/tmp/c++/out/main
/tmp/ccBwxewk.o: In function `main':
/mnt/d/tmp/c++/source/main.cpp:8: undefined reference to `test_add()'
collect2: error: ld returned 1 exit status

tasks.json -g 后面的参数改为 “${workspaceFolder}/source/*.cpp”

2. /mnt/d/tmp/c++/source/add.cpp:3:10: fatal error: add.h: No such file or directory

Starting build...
/usr/bin/g++ -g /mnt/d/tmp/c++/source/*.cpp -o /mnt/d/tmp/c++/out/main
/mnt/d/tmp/c++/source/add.cpp:3:10: fatal error: add.h: No such file or directory
 #include "add.h"
          ^~~~~~~
compilation terminated.
/mnt/d/tmp/c++/source/main.cpp:2:10: fatal error: add.h: No such file or directory
 #include 
          ^~~~~~~
compilation terminated.

Build finished with error(s).
The terminal process failed to launch (exit code: -1).

tasks.json 加上"-I", “${workspaceFolder}/include”,

c_cpp_properties.json

c_cpp_properties.json配置文件默认是不会产生的，ctrl+shift+p 再输入configuration选择后便会出现。

在这里我们可以设置 includePath

{
    "configurations": [
        {
            "name": "Linux",
            "includePath": [
                "${workspaceFolder}/**",
                "${workspaceFolder}/include/**"  //your include path
            ],
            "defines": [],
            "compilerPath": "/usr/bin/gcc",
            "cStandard": "gnu11",
            "cppStandard": "gnu++14",
            "intelliSenseMode": "linux-gcc-x64"
        }
    ],
    "version": 4
}

注：请注意，这里使用是的WSL环境下的g++。