Conversion error while trying to use CreateProcess Windows API-CodePudding

I am trying to run a C program that creates a process:

int main()
{
    HANDLE hProcess;
    HANDLE hThread;
    STARTUPINFO si;
    PROCESS_INFORMATION pi;
    DWORD dwProcessId = 0;
    DWORD dwThreadId = 0;
    ZeroMemory(&si, sizeof(si));
    ZeroMemory(&pi, sizeof(pi));
    BOOL bCreateProcess = NULL;
    
    bCreateProcess = CreateProcessW(L"C:\\Windows\\System32\\notepad.exe", NULL, NULL, NULL, FALSE, 0, NULL, NULL, &si, &pi);
                            
    if (bCreateProcess == FALSE) {
        cout << "Create Process Failed & Error No. " << GetLastError() << endl;
    }
    
    cout << "Process Creation Successful!" << endl;
    
    cout << "Process ID: " << pi.dwProcessId << endl;
    cout << "Thread ID: " << pi.dwThreadId << endl;
    cout << "GetProcessID: " << GetProcessId(pi.hProcess) << endl;
    cout << "GetThreadID: " << GetThreadId(pi.hThread) << endl;
    
    WaitForSingleObject(pi.hProcess, INFINITE);
    
    CloseHandle(pi.hThread);
    CloseHandle(pi.hProcess);

    return 0;
}

However, I returns the following error:

main.cpp(19): error C2664: 'BOOL CreateProcessW(LPCWSTR,LPWSTR,LPSECURITY_ATTRIBUTES,LPSECURITY_ATTRIBUTES,BOOL,DWORD,LPVOID,LPCWSTR,LPSTARTUPINFOW,LPPROCESS_INFORMATION)': cannot convert argument 9 from 'LPSTARTUPINFOW *' to 'LPSTARTUPINFOW'
main.cpp(27): note: Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast
C:\Program Files (x86)\Windows Kits\10\include\10.0.20348.0\um\processthreadsapi.h(372): note: see declaration of 'CreateProcessW'

I am compiling it on Windows 10 using the following command:

cl.exe /EHsc main.cpp

Also, if you could please suggest some tutorials (courses, book, youtube channels, blogs, etc.) for Windows system programming.

CodePudding user response：

It seems you are compiling with Ansi strings rather than Wide strings, so STARTUPINFO becomes STARTUPINFOA, which is incompatible with CreateProcessW().

When I compile your code, I get error cannot convert argument 9 from 'STARTUPINFO *' to 'LPSTARTUPINFOW', which makes more sense than the error you posted.

Either change the compiler options or write STARTUPINFOW si; in your code.