Specify command-line C++ version for cl.exe (Visual Studio Code) - c++

Question

I'm testing the C++17 fallthrough attribute in Visual Studio Code. The IDE has been configured to compile C/C++ code using the Microsoft Visual Studio cl.exe compiler. My task definition (in tasks.json) to build a simple .cpp file in DEBUG mode is:
{
"type": "shell",
"label": "cl.exe: Build active file",
"command": "cl.exe",
"args": [
"/Zi",
"/EHsc",
"/Fe:",
"${file}",
"/link",
"/OUT:${fileDirname}\\${fileBasenameNoExtension}.exe"
],
"options": {
"cwd": "${workspaceFolder}"
},
"problemMatcher": [
"$msCompile"
]
}
This has been tested on several programs and works well. Now I include a switch statement using the new [[fallthrough]]; attribute and the compiler generates:
warning C5051: attribute 'fallthrough' requires at least '/std:c++17'; ignored
Adding "/std:c++17", to the "args" for cl.exe changed nothing (the same compiler warning is generated). Here is the new version:
"args": [
"/Zi",
"/EHsc",
"/Fe:",
"/std:c++17",
"${file}",
"/link",
"/OUT:${fileDirname}\\${fileBasenameNoExtension}.exe"
],
As far as I can see, my syntax is correct according to the Microsoft documentation for specifying the language standard.
What am I doing wrong?

Answer 1

I found this issue while searching for something else, but here's a fix for you :).
Your problem is the order in which you supply the arguments. /Fe: is expecting the file path straight after - https://learn.microsoft.com/en-us/cpp/build/reference/fe-name-exe-file?view=msvc-160
Here's an example args section taken from the VSCode documentation but I've added the /std:c++17 compiler flag
"args": [
"/Zi",
"/EHsc",
"/std:c++17", // <= put your compiler flag here
"/Fe:", // <= /Fe: followed by the path + filename
"${fileDirname}\\${fileBasenameNoExtension}.exe",
"${file}"
]
Hope this helps, happy coding!