Execute windows command and get results as string | Capture Output of Spawned Process to string

WindowsCommandOutput.cpp

//
// Execute a command and get the results in a CString. (Only standard output)
//
CStringA ExecCmd(
    const wchar_t* cmd              // [in] command to execute
)
{
    CStringA strResult;
    HANDLE hPipeRead, hPipeWrite;

    SECURITY_ATTRIBUTES saAttr = { sizeof(SECURITY_ATTRIBUTES) };
    saAttr.bInheritHandle = TRUE;   //Pipe handles are inherited by child process.
    saAttr.lpSecurityDescriptor = NULL;

    // Create a pipe to get results from child's stdout.
    if ( !CreatePipe(&hPipeRead, &hPipeWrite, &saAttr, 0) )
        return strResult;

    STARTUPINFO si = { sizeof(STARTUPINFO) };
    si.dwFlags     = STARTF_USESHOWWINDOW | STARTF_USESTDHANDLES;
    si.hStdOutput  = hPipeWrite;
    si.hStdError   = hPipeWrite;
    si.wShowWindow = SW_HIDE;       // Prevents cmd window from flashing. Requires STARTF_USESHOWWINDOW in dwFlags.

    PROCESS_INFORMATION pi  = { 0 };

    BOOL fSuccess = CreateProcessW( NULL, (LPWSTR)cmd, NULL, NULL, TRUE, CREATE_NEW_CONSOLE, NULL, NULL, &si, &pi);
    if (! fSuccess)
    {
        CloseHandle( hPipeWrite );
        CloseHandle( hPipeRead );
        return strResult;
    }

    bool bProcessEnded = false;
    for (; !bProcessEnded ;)
    {
        // Give some timeslice (50ms), so we won't waste 100% cpu.
        bProcessEnded = WaitForSingleObject( pi.hProcess, 50) == WAIT_OBJECT_0;

        // Even if process exited - we continue reading, if there is some data available over pipe.
        for (;;)
        {
            char buf[1024];
            DWORD dwRead = 0;
            DWORD dwAvail = 0;

            if (!::PeekNamedPipe(hPipeRead, NULL, 0, NULL, &dwAvail, NULL))
                break;

            if (!dwAvail) // no data available, return
                break;

            if (!::ReadFile(hPipeRead, buf, min(sizeof(buf) - 1, dwAvail), &dwRead, NULL) || !dwRead)
                // error, the child process might ended
                break;

            buf[dwRead] = 0;
            strResult += buf;
        }
    } //for

    CloseHandle( hPipeWrite );
    CloseHandle( hPipeRead );
    CloseHandle( pi.hProcess );
    CloseHandle( pi.hThread );
    return strResult;
} //ExecCmd

Credit: http://stackoverflow.com/a/35658917/2628257