如果先安装 vscode 再配置 path 可能会造成 vscode 识别不到 includePath 或直接使用 MSVC，此时可以正常编译，但是不能够使用代码补全。

使用以下命令获取 includePath。

g++ -v -x c++ -E -

可以见到如下内容：

 D:/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/8.1.0/include/c++
 D:/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/8.1.0/include/c++/x86_64-w64-mingw32
 D:/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/8.1.0/include/c++/backward
 D:/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/8.1.0/include
 D:/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/8.1.0/include-fixed
 D:/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/8.1.0/../../../../x86_64-w64-mingw32/include

将其全部写入 c_cpp_properties.json 即可，如下所示：

{
    "configurations": [
        {
            "name": "Win32",
            "includePath": [
                "${workspaceFolder}/**",
                "D:/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/8.1.0/include/c++",
                "D:/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/8.1.0/include/c++/x86_64-w64-mingw32",
                "D:/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/8.1.0/include/c++/backward",
                "D:/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/8.1.0/include",
                "D:/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/8.1.0/include-fixed",
                "D:/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/8.1.0/../../../../x86_64-w64-mingw32/include"
            ],
            "defines": [
                "_DEBUG",
                "UNICODE",
                "_UNICODE"
            ],
            "compilerPath": "D:/mingw64/bin/g++.exe",
            "cStandard": "c17",
            "cppStandard": "c++14",
            "intelliSenseMode": "windows-gcc-x64"
        }
    ],
    "version": 4
}