如何获得当前的Windows系统范围内的计时器分辨率 [英] How to get the current Windows system-wide timer resolution

问题描述

我知道，默认值是15.6＆NBSP;每个时钟毫秒，但有些失败者可能会改变它，然后来回换一次又一次，我需要轮询当前值是什么进行有效QueryPerformanceCounter的同步

那么，有没有一个API的方式，以得到定时器分辨率？

我在C ++ BTW。

解决方案

的Windows计时器的分辨率是由隐藏的API调用提供的：

  NTSTATUS NtQueryTimerResolution（OUT PULONG MinimumResolution，
                                OUT PULONG MaximumResolution，
                                OUT PULONG ActualResolution）;
 

NtQueryTimerResolution是由本地的Windows NT库ntdll.dll输出。

通用硬件平台156,250报告或为100144的 ActualResolution 的;旧平台可能会报告甚至更大的数字;较新的系统中，当HPET（高precision事件定时器）或恒定/ TSC不变的支持格外，可能为ActualResolution返回156001。

拨打 timeBeginPeriod（N）反映在的 ActualResolution 的

在更多细节这个答案

I know that the default is 15.6 ms per tick, but some loser may change it and then change back and forth again and again, and I need to poll what the current value is to perform valid QueryPerformanceCounter synchronization.

So is there an API way to get the timer resolution?

I'm on C++ BTW.

解决方案

Windows timer resolution is provided by the hidden API call:

NTSTATUS NtQueryTimerResolution(OUT PULONG MinimumResolution, 
                                OUT PULONG MaximumResolution, 
                                OUT PULONG ActualResolution);

NtQueryTimerResolution is exported by the native Windows NT library NTDLL.DLL.

Common hardware platforms report 156,250 or 100,144 for ActualResolution; older platforms may report even larger numbers; newer systems, particulary when HPET (High Precision Event Timer) or constant/invariant TSC are supported, may return 156,001 for ActualResolution.

Calls to timeBeginPeriod(n) are reflected in ActualResolution.

More details in this answer.

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