C++ Multibyte/wide character conversions (cuchar) not working in MS VS Code?

Question

I've recently started using Microsoft Visual Studio Code on my Windows PC and integrated the terminal with it to run/debug C/C++ programs (reference: How to Write And Run C and C++ Code in Visual Studio Code).

However, while executing certain programs, I'm getting compilation error messages such as below:

'mbrtoc16' has not been declared in '::'
'c16rtomb' has not been declared in '::'
'mbrtoc32' has not been declared in '::'
'c32rtomb' has not been declared in '::'

May I get help on fixing these, please? I get the errors while debugging/running the below C++ program in VS Code:

#include <bits/stdc++.h>

using namespace std;

string ltrim(const string &);
string rtrim(const string &);
vector<string> split(const string &);

vector<int> freqQuery(vector<vector<int>> queries) {
    int index=0, choice, value, flag;
    vector<int> result;
    unordered_map<int,int> contents;
    unordered_map<int,int> :: iterator content_itr;
    vector<vector<int>> :: iterator query_itr = queries.begin();
    while(query_itr < queries.end()){
        choice = query_itr[0][0];
        value = query_itr[0][1];
        flag = -1;
        if(choice == 1){
            content_itr = contents.find(value);
            if(content_itr == contents.end())
                contents.insert(make_pair(value, 1));                
            else
                content_itr->second += 1;                
        }   
        else if(choice == 2) {
            content_itr = contents.find(value);
            if(content_itr != contents.end())
                content_itr->second -= 1;
        }
        else if (choice == 3){
            for(content_itr = contents.begin(); content_itr != contents.end(); content_itr++)
                if(content_itr->second == value){
                    flag=1;
                    break;
                }
            if(flag == 1)
                result.push_back(1);
            else
                result.push_back(0);
        }
        query_itr++;
    }
    
    return result;
}

int main()
{
    ofstream fout(getenv("OUTPUT_PATH"));

    string q_temp;
    getline(cin, q_temp);

    int q = stoi(ltrim(rtrim(q_temp)));

    vector<vector<int>> queries(q);

    for (int i = 0; i < q; i++) {
        queries[i].resize(2);

        string queries_row_temp_temp;
        getline(cin, queries_row_temp_temp);

        vector<string> queries_row_temp = split(rtrim(queries_row_temp_temp));

        for (int j = 0; j < 2; j++) {
            int queries_row_item = stoi(queries_row_temp[j]);

            queries[i][j] = queries_row_item;
        }
    }

    vector<int> ans = freqQuery(queries);

    for (int i = 0; i < ans.size(); i++) {
        fout << ans[i];

        if (i != ans.size() - 1) {
            fout << "\n";
        }
    }

    fout << "\n";

    fout.close();

    return 0;
}

string ltrim(const string &str) {
    string s(str);

    s.erase(
        s.begin(),
        find_if(s.begin(), s.end(), not1(ptr_fun<int, int>(isspace)))
    );

    return s;
}

string rtrim(const string &str) {
    string s(str);

    s.erase(
        find_if(s.rbegin(), s.rend(), not1(ptr_fun<int, int>(isspace))).base(),
        s.end()
    );

    return s;
}

vector<string> split(const string &str) {
    vector<string> tokens;

    string::size_type start = 0;
    string::size_type end = 0;

    while ((end = str.find(" ", start)) != string::npos) {
        tokens.push_back(str.substr(start, end - start));

        start = end + 1;
    }

    tokens.push_back(str.substr(start));

    return tokens;
}

One way I could figure out to suppress those errors is by commenting out the the line #include <cuchar> in the header file named stdc++.h. However, I believe this is just a workaround that might impact something else possibly, and not an absolute solution.