c++ - timeEndPeriod 是恢复之前的值还是默认值？

Question

假设默认计时器分辨率为 15 毫秒。鉴于这种情况:

Process A calls timeBeginPeriod(1);
Now timer resolution is 1ms.
Process B calls timeBeginPeriod(2);
Now timer resolution is 2ms.
Process B calls timeEndPeriod(2);

那么定时器分辨率是多少？它会回落到 1 毫秒还是 15 毫秒？

让我们稍微修改一下场景:

Process A calls timeBeginPeriod(1);
Now timer resolution is 1ms.
Process B calls timeBeginPeriod(2);
Now timer resolution is 2ms.
Process A calls timeEndPeriod(1);

现在定时器分辨率是多少？它是否停留在 2ms 直到进程 B 调用 timeEndPeriod(2)？

Answer 1

来自 MSDN:

Windows uses the lowest value (that is, highest resolution) requested by any process.

假设您的进程是唯一调用 timeBeginPeriod() 的进程，那么:

Q: What is the timer resolution then? Does it fall back to 1 or 15ms?

它没有改变，因为 1 毫秒(进程 A 要求的)是最低分辨率(然后是应用的分辨率)。所以答案是:它是 1 毫秒，当进程 B 发出请求时它没有改变，因为它是一个全局设置，然后应用了最严格(最低)的设置。

Q: Now what is the timer resolution? Does it stay at 2ms until process B calls timeEndPeriod(2)?

是的，因为现在要求的最低分辨率是 2 毫秒，所以系统将遵守该请求，直到调用 timeEndPeriod(2)。