not accepting code of "c++17" or "gnu++17" unable to compile code

Issue Type: Bug

Trying to run code which have "constexpr" keyword and continiously getting this error , the same code is successfully compiled in codeblock.
Note: Also checked by changing cppstandard setting to "c++17" and "gnu++17" but still same error

[Running] cd "d:\codeblock" && g++ t.cpp -o t && "d:\codeblock"t
t.cpp: In member function 'void Solution_3sum::nSumStep(const int*, const int*, int, FoundNums ...)':
t.cpp:178:12: warning: 'if constexpr' only available with -std=c++17 or -std=gnu++17
if constexpr (count == 2)

Extension version: 1.2.2
VS Code version: Code 1.54.2 (fd6f3bce6709b121a895d042d343d71f317d74e7, 2021-03-11T00:56:19.848Z)
OS version: Windows_NT x64 10.0.19042

System Info

Item	Value
CPUs	Intel(R) Core(TM) i3-6006U CPU @ 2.00GHz (4 x 1992)
GPU Status	2d_canvas: enabled gpu_compositing: enabled multiple_raster_threads: enabled_on oop_rasterization: enabled opengl: enabled_on protected_video_decode: unavailable_off rasterization: enabled skia_renderer: enabled_on video_decode: enabled vulkan: disabled_off webgl: enabled webgl2: enabled
Load (avg)	undefined
Memory (System)	3.90GB (0.64GB free)
Process Argv	--crash-reporter-id 05c17531-75db-4467-a8a7-f1e58ae986c6
Screen Reader	no
VM	0%

A/B Experiments

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pythontbcf:30265426
vspre833:30267464

[michelleangela]

@mdsadiqueinam

This sounds like a compiler argument configuration issue and not an issue with the C++ extension. Please note the C++ extension does not provide compiling features, for example it does not provide compilers and it does not configure what arguments to provide compilers.

What compiler is used on Codeblocks IDE and how is it configured or what arguments are passed to it? What compiler is being using on VS Code and what arguments are passed to it? Are you using VS Code's tasks.json to build?

Since I am beginner in programming I don't know that much, but I know that MinGw is used as a compiler in codeblock IDE which was installed along with it and I set the same compiler on VScode and yes I do have task.json and I also set c++17 in there

[sean-mcmanus]

What is the output of running your task.json?

Starting build...
"C:\Program Files\mingw-w64\x86_64-8.1.0-posix-seh-rt_v6-rev0\mingw64\bin\gcc.exe" -g D:\codeblock.vscode\tasks.json -o D:\codeblock.vscode\tasks.exe --std c++17
C:/Program Files/mingw-w64/x86_64-8.1.0-posix-seh-rt_v6-rev0/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/8.1.0/../../../../x86_64-w64-mingw32/bin/ld.exe:D:\codeblock.vscode\tasks.json: file format not recognized; treating as linker script
C:/Program Files/mingw-w64/x86_64-8.1.0-posix-seh-rt_v6-rev0/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/8.1.0/../../../../x86_64-w64-mingw32/bin/ld.exe:D:\codeblock.vscode\tasks.json:1: syntax error
collect2.exe: error: ld returned 1 exit status

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

[sean-mcmanus]

--std c++17 is not valid input to gcc. Does using -std=c++17 fix your issue?

no still same issue
{ "tasks": [ { "type": "cppbuild", "label": "C/C++: gcc.exe build active file", "command": "C:\\Program Files\\mingw-w64\\x86_64-8.1.0-posix-seh-rt_v6-rev0\\mingw64\\bin\\gcc.exe", "args": [ "-g", "${file}", "-o", "${fileDirname}\\${fileBasenameNoExtension}.exe", "-std", "c++17" ], "options": { "cwd": "${workspaceFolder}" }, "problemMatcher": [ "$gcc" ], "group": { "kind": "build", "isDefault": true }, "detail": "Task generated by Debugger." } ], "version": "2.0.0" }
Starting build...
"C:\Program Files\mingw-w64\x86_64-8.1.0-posix-seh-rt_v6-rev0\mingw64\bin\gcc.exe" -g D:\codeblock.vscode\tasks.json -o D:\codeblock.vscode\tasks.exe -std c++17
gcc.exe: error: c++17: No such file or directory
gcc.exe: error: unrecognized command line option '-std'; did you mean '-mrtd'?

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

{ "tasks": [ { "type": "cppbuild", "label": "C/C++: gcc.exe build active file", "command": "C:\\Program Files\\mingw-w64\\x86_64-8.1.0-posix-seh-rt_v6-rev0\\mingw64\\bin\\gcc.exe", "args": [ "-g", "${file}", "-o", "${fileDirname}\\${fileBasenameNoExtension}.exe", "-std=c++17" ], "options": { "cwd": "${workspaceFolder}" }, "problemMatcher": [ "$gcc" ], "group": { "kind": "build", "isDefault": true }, "detail": "Task generated by Debugger." } ], "version": "2.0.0" }
Starting build...
"C:\Program Files\mingw-w64\x86_64-8.1.0-posix-seh-rt_v6-rev0\mingw64\bin\gcc.exe" -g D:\codeblock.vscode\tasks.json -o D:\codeblock.vscode\tasks.exe -std=c++17
C:/Program Files/mingw-w64/x86_64-8.1.0-posix-seh-rt_v6-rev0/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/8.1.0/../../../../x86_64-w64-mingw32/bin/ld.exe:D:\codeblock.vscode\tasks.json: file format not recognized; treating as linker script
C:/Program Files/mingw-w64/x86_64-8.1.0-posix-seh-rt_v6-rev0/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/8.1.0/../../../../x86_64-w64-mingw32/bin/ld.exe:D:\codeblock.vscode\tasks.json:1: syntax error
collect2.exe: error: ld returned 1 exit status

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

[sean-mcmanus]

It looks like you fixed the c++17 issue, but you need to run the build task with a .cpp file active and not the tasks.json file active. Does that fix your issues?

You mean I have to change the tasks extension from .json to .cpp

[sean-mcmanus]

No. The build task is setup to reference the currently active file, so you just need to make the .cpp file active and then run the build task in order to build the .cpp; otherwise, it tries to build the tasks.json file.

[michelleangela]

For clarification, a "currently active file" is the file that's currently open or in view in the VS Code editor.

still having some errors(s)

Starting build...
"C:\Program Files\mingw-w64\x86_64-8.1.0-posix-seh-rt_v6-rev0\mingw64\bin\gcc.exe" -g D:\codeblock\MergeSortLinkedList.cpp -o D:\codeblock\MergeSortLinkedList.exe -std=c++17
C:\Users\mdsad\AppData\Local\Temp\ccgbG5xi.o: In function push(Node**, int)': D:/codeblock/MergeSortLinkedList.cpp:86: undefined reference to operator new(unsigned long long)'
C:\Users\mdsad\AppData\Local\Temp\ccgbG5xi.o: In function main': D:/codeblock/MergeSortLinkedList.cpp:94: undefined reference to std::istream::operator>>(long&)'
D:/codeblock/MergeSortLinkedList.cpp:98: undefined reference to std::istream::operator>>(long&)' D:/codeblock/MergeSortLinkedList.cpp:100: undefined reference to std::istream::operator>>(long&)'
C:\Users\mdsad\AppData\Local\Temp\ccgbG5xi.o: In function __tcf_0': C:/Program Files/mingw-w64/x86_64-8.1.0-posix-seh-rt_v6-rev0/mingw64/lib/gcc/x86_64-w64-mingw32/8.1.0/include/c++/iostream:74: undefined reference to std::ios_base::Init::~Init()'
C:\Users\mdsad\AppData\Local\Temp\ccgbG5xi.o: In function __static_initialization_and_destruction_0': C:/Program Files/mingw-w64/x86_64-8.1.0-posix-seh-rt_v6-rev0/mingw64/lib/gcc/x86_64-w64-mingw32/8.1.0/include/c++/iostream:74: undefined reference to std::ios_base::Init::Init()'
C:\Users\mdsad\AppData\Local\Temp\ccgbG5xi.o:MergeSortLinkedList.cpp:(.rdata$.refptr._ZSt3cin[.refptr._ZSt3cin]+0x0): undefined reference to `std::cin'
collect2.exe: error: ld returned 1 exit status

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

[sean-mcmanus]

Does switching from gcc.exe to g++.exe fix it?