c++ createprocess - string var for cmd line parameter - nothing happening

Question

So I'm trying to create a process using string variables.

STARTUPINFO si;
PROCESS_INFORMATION pi;
ZeroMemory(&si, sizeof(si));
ZeroMemory(&pi, sizeof(pi));

si.cb = sizeof(si);

std::string cmd_line = game_path + " " + std::string(game_params);

std::cout << cmd_line << "\n";

if (!CreateProcess(NULL, LPTSTR(cmd_line.c_str()), NULL, NULL, FALSE, 0, NULL, NULL, &si, &pi)) {
    std::cout << "fail\n";
    return false;
}

The output from cout cmd_line is the correct path and parameters:

C:\\Program Files (x86)\\My_Game\\Game.exe -test -admin

The createprocess call is returning false, but I'm not sure exactly why. I'm pretty new to this so any help and advice would be great.

Answer 1

int _tmain(int argc, _TCHAR* argv[])
{
    STARTUPINFO si;
    PROCESS_INFORMATION pi;
    ZeroMemory(&si, sizeof(si));
    ZeroMemory(&pi, sizeof(pi));

    si.cb = sizeof(si);

    std::string game_path = "C:\\Windows\\system32\\calc.exe";
    std::string game_params = "-test -admin";

    std::string cmd_line = game_path + " " + std::string(game_params);

    std::cout<<cmd_line << "\n";

    TCHAR tszCmdLine[1024] = {0};
    mbstowcs(tszCmdLine, cmd_line.c_str(), 1024);
    _tprintf(tszCmdLine);

    if (!CreateProcess(NULL, tszCmdLine, NULL, NULL, FALSE, 0, NULL, NULL, &si, &pi)) {
        std::cout<<"fail\n"<<GetLastError();
        return false;
    }
}

const char* cannot be parameter of CreateProcess() . You have to make char* string to tchar* string using mbstowcs()

Answer 2

I've test your code.

The result of GetLastError() is 2.

That is The system cannot find the file specified.

Use MultiByteToWideChar to convert char* string to TCHAR* string.

MultiByteToWideChar(LC_ALL, 0, cmd_line.c_str(), -1, str_command, MAX_PATH);