[cpptools] Unknown C++ standard control flag: -std=gnu++2b

[Wongboo]

Brief Issue Summary

I think it's bug about C/C++ extension doesn't support control flag: -std=gnu++2b, anyway it eventually pops up in CMake/Build

CMake Tools Diagnostics

I cannot run CMake: Log Diagnostics, insteead run C/C++: Log Diagnostics

Version: 1.6.0
Current Configuration:
{
    "name": "Win32",
    "includePath": [
        "${workspaceFolder}/**",
        "${vcpkgRoot}/x64-windows/include"
    ],
    "defines": [
        "_DEBUG",
        "UNICODE",
        "_UNICODE"
    ],
    "windowsSdkVersion": "10.0.19041.0",
    "compilerPath": "C:\\Program Files (x86)\\Microsoft Visual Studio\\2019\\Community\\VC\\Tools\\MSVC\\14.29.30133\\bin\\Hostx64\\x64\\cl.exe",
    "cStandard": "c17",
    "intelliSenseMode": "windows-msvc-x64",
    "compilerArgs": [],
    "cppStandard": "c++20",
    "intelliSenseModeIsExplicit": false,
    "cStandardIsExplicit": false,
    "cppStandardIsExplicit": true,
    "compilerPathIsExplicit": false,
    "browse": {
        "path": [
            "${workspaceFolder}/**",
            "${vcpkgRoot}/x64-windows/include"
        ],
        "limitSymbolsToIncludedHeaders": true
    }
}

Debug Log

[cpptools] Unknown C++ standard control flag: -std=gnu++2b
[cpptools] Unknown standard control flag: -std=gnu++2b
[cpptools] Unknown C++ standard control flag: -std=gnu++2b
[cpptools] Unknown standard control flag: -std=gnu++2b
[cpptools] Unknown C++ standard control flag: -std=gnu++2b
[cpptools] Unknown standard control flag: -std=gnu++2b
[cpptools] Unknown C++ standard control flag: -std=gnu++2b
[cpptools] Unknown standard control flag: -std=gnu++2b
[cpptools] Unknown C++ standard control flag: -std=gnu++2b
[cpptools] Unknown standard control flag: -std=gnu++2b

[linquize]

It seems you are using MSVC.
gnu++2b is for GCC.

[linquize]

Where do you put gnu++2b flag?

[Wongboo]

I'm using Clang 12.0.0 (GNU CLI) for MSVC 16.11.31702.278 (Visual Studio Community 2019 Release - amd64), so I can put gnu++2b while seems to be using MSVC, and that's just intellisence mode which shouldn't bother, once I set CMAKE_CXX_STANDARD to 20, it disappears, so it must be plugin's problem

[linquize]

gnu++2b is C++23, not C++20

[Wongboo]

@linquize , clearly you misundertand me for multiple times, when I set CMAKE_CXX_STANDARD to 23, the bug appears, to 20, it disappears, am I clear?

[andreeis]

@Wongboo, thank you for opening this report. We will fix this.

[andreeis]

This fix is included in the 1.9.0 CMake Tools release. Please upgrade your extension in VSCode and let us know if you encounter any other issues.

[Wongboo]

I think the same issue appears for -std=c2x, for CMAKE_C_STANDARD

[andreeis]

@Wongboo, thank you for pointing that out. We fixed the remaining C standard bug in CMake Tools 1.9.1 which was just released. Please try it and let us know if you encounter any other issues.