c++ - Windows 操作系统多久可以从唤醒计时器唤醒？

Question

我正在使用 C++ 和 Win API 编写程序。我使用SetSuspendState () API 将系统发送到睡眠模式（有可能在唤醒计时器上唤醒，'DisableWakeEvent' 设置为 FALSE。）然后我使用 CreateWaitableTimer 和 SetWaitableTimer API 来设置实际计时器。问题是如果我在系统进入睡眠模式后过早设置唤醒定时器，有时系统不会唤醒。

所以我很好奇，自从系统进入睡眠模式后，是否必须经过最短时间才能通过唤醒定时器以编程方式唤醒它？

Answer 1

马上。您的 PC 可以使用计时器唤醒：

安排机器唤醒

C# 文章，如果你不介意的话：http: //www.codeproject.com/Articles/49798/Wake-the-PC-from-standby-or-hibernation

using System;
using System.Text;
using System.Runtime.InteropServices;
using Microsoft.Win32.SafeHandles;
using System.ComponentModel;
using System.Threading;

namespace WakeUPTimer
{
    class WakeUP
    {
        [DllImport("kernel32.dll")]
        public static extern SafeWaitHandle CreateWaitableTimer(IntPtr lpTimerAttributes, 
                                                                  bool bManualReset,
                                                                string lpTimerName);

        [DllImport("kernel32.dll", SetLastError = true)]
        [return: MarshalAs(UnmanagedType.Bool)]
        public static extern bool SetWaitableTimer(SafeWaitHandle hTimer, 
                                                    [In] ref long pDueTime, 
                                                              int lPeriod,
                                                           IntPtr pfnCompletionRoutine, 
                                                           IntPtr lpArgToCompletionRoutine, 
                                                             bool fResume);

        public event EventHandler Woken;

        private BackgroundWorker bgWorker = new BackgroundWorker();

        public WakeUP()
        {
            bgWorker.DoWork += new DoWorkEventHandler(bgWorker_DoWork);
            bgWorker.RunWorkerCompleted += 
              new RunWorkerCompletedEventHandler(bgWorker_RunWorkerCompleted);
        }

        public void SetWakeUpTime(DateTime time)
        {
            bgWorker.RunWorkerAsync(time.ToFileTime());
        }

        void bgWorker_RunWorkerCompleted(object sender, 
                      RunWorkerCompletedEventArgs e)
        {
            if (Woken != null)
            {
                Woken(this, new EventArgs());
            }
        }

        private void bgWorker_DoWork(object sender, DoWorkEventArgs e) 
        {
            long waketime = (long)e.Argument;

            using (SafeWaitHandle handle = 
                      CreateWaitableTimer(IntPtr.Zero, true, 
                      this.GetType().Assembly.GetName().Name.ToString() + "Timer"))
            {
                if (SetWaitableTimer(handle, ref waketime, 0, 
                                       IntPtr.Zero, IntPtr.Zero, true))
                {
                    using (EventWaitHandle wh = new EventWaitHandle(false, 
                                                           EventResetMode.AutoReset))
                    {
                        wh.SafeWaitHandle = handle;
                        wh.WaitOne();
                    }
                }
                else
                {
                    throw new Win32Exception(Marshal.GetLastWin32Error());
                }
            }
        }

    }
}

或从控制面板：http ://www.anuko.com/content/world_clock/faq/enable_wake_timers.htm