System.Diagnostics.Process.WaitForInputIdleCore C# (CSharp) Method

        private bool WaitForInputIdleCore(int milliseconds)
        {
            const int WAIT_OBJECT_0 = 0x00000000;
            const int WAIT_FAILED = unchecked((int)0xFFFFFFFF);
            const int WAIT_TIMEOUT = 0x00000102;

            
            bool idle;
            using (SafeProcessHandle handle = GetProcessHandle(Interop.Advapi32.ProcessOptions.SYNCHRONIZE | Interop.Advapi32.ProcessOptions.PROCESS_QUERY_INFORMATION))
            {
                int ret = Interop.User32.WaitForInputIdle(handle, milliseconds);
                switch (ret)
                {
                    case WAIT_OBJECT_0:
                        idle = true;
                        break;
                    case WAIT_TIMEOUT:
                        idle = false;
                        break;
                    case WAIT_FAILED:
                    default:
                        throw new InvalidOperationException(SR.InputIdleUnkownError);
                }
            }
            return idle;
        }