C++ requires keyword does not work, compiler error [duplicate] - c++

Question

This question already has answers here:
Visual Studio Code: how to add arguments for g++ compiler?
(2 answers)
Closed 10 months ago.
Code is supposed to work but it gives compiler error:
#include <iostream>
#include <concepts>
using namespace std;
template <typename T> requires integral<T>
T add( T a, T b){
return a + b;
}
int main(){
char a_0{10};
char a_1{20};
auto result_a = add(a_0,a_1);
cout << "result_a : " << static_cast<int>(result_a) << endl;
int b_0{11};
int b_1{5};
auto result_b = add(b_0,b_1);
cout << "result_b : " << result_b << endl;
return 0;
}
Compiler error:
error: 'requires' does not name a type;
6 | requires integral
Im using vs code and mingw64 from this site: https://winlibs.com
Here is my vscode task.json file:
{
"version": "2.0.0",
"tasks": [
{
"type": "cppbuild",
"label": "C/C++: g++.exe build active file",
"command": "C:\\mingw64\\bin\\g++.exe",
"args": [
"-fdiagnostics-color=always",
"-g",
"${file}",
"-o",
"${fileDirname}\\${fileBasenameNoExtension}.exe"
],
"options": {
"cwd": "${fileDirname}"
},
"problemMatcher": [
"$gcc"
],
"group": {
"kind": "build",
"isDefault": true
},
"detail": "compiler: C:\\mingw64\\bin\\g++.exe"
}
]
}

Answer 1

requires is a keyword available since C++20.
To compile this code using GCC, specify -std=c++20 as a command-line argument.
{
"version": "2.0.0",
"tasks": [
{
"type": "cppbuild",
"label": "C/C++: g++.exe build active file",
"command": "C:\\mingw64\\bin\\g++.exe",
"args": [
"-fdiagnostics-color=always",
"-g",
"${file}",
"-std=c++20",
"-o",
"${fileDirname}\\${fileBasenameNoExtension}.exe"
],
"options": {
"cwd": "${fileDirname}"
},
"problemMatcher": [
"$gcc"
],
"group": {
"kind": "build",
"isDefault": true
},
"detail": "compiler: C:\\mingw64\\bin\\g++.exe"
}
]
}