How to create an independent process?

Question

C++ / C#

Unable to create independent twin process using WinApi methods.
I use the CreateProcess(...) method, and a new process is launched, but if it is closed, the parent is also closed.
And it is necessary that the state does not affect each other
. Here is the code:

int main() {
    int a;
    STARTUPINFO si;
    PROCESS_INFORMATION pi;

    ZeroMemory(&si, sizeof(si));
    si.cb = sizeof(si);
    ZeroMemory(&pi, sizeof(pi));

    si.wShowWindow = SW_HIDE;
    si.dwFlags = STARTF_USEPOSITION | STARTF_USESIZE;

    char szFileName[FILENAME_MAX];
    szFileName[0] = '\0';

    GetModuleFileName(NULL, szFileName, FILENAME_MAX);

    std::cout << "enter - ";
    std::cin >> a;
    if (a == 1) {
        CreateProcess(szFileName, NULL, NULL, NULL, FALSE, CREATE_NEW_CONSOLE, NULL, NULL, &si, &pi);

        WaitForSingleObject(pi.hProcess, INFINITE);

        CloseHandle(pi.hProcess);
        CloseHandle(pi.hThread);
    } else
        std::cout << "Shh";

    return 0;
}

Answer 1

if (a == 1) {
        CreateProcess(szFileName, NULL, NULL, NULL, FALSE, CREATE_NEW_CONSOLE, NULL, NULL, &si, &pi);
        WaitForSingleObject(pi.hProcess, INFINITE);
        ...
    }
    ...
    return 0;

a new process is launched, but if it is closed, the parent is also closed.

Well, that's exactly what you wrote: the parent starts the process and waits for its completion, and after that it ends itself. If you want other behavior, write another behavior.