timestamp in milliseconds in Windows

Question

I need to measure two separate events in time and compare them (not in the same application), so I would like to know the timestamp from the same reference (different applications on the same machine).

What's the simplest way of doing this on a Windows system? I've read about gettimeofday but that seems to be a Unix-specific function.

Also I don't want to use boost or any other external library (windows libraries are fine).

Note you'll likely only be getting millisecond *precision*, not millisecond *accuracy*. — Timothy Shields, Aug 26 '13 at 17:05
@TimothyShields: He said he has the same reference (same machine, different processes), so precision is the concern here. That said, having a return value in units of milliseconds (or smaller) doesn't guarantee millisecond precision. — Ben Voigt, Aug 26 '13 at 17:06
[Accuracy and precision](http://en.wikipedia.org/wiki/Accuracy_and_precision) - read this. — Timothy Shields, Aug 26 '13 at 17:06
More important is the difference between *precision* and *resolution*. — Ben Voigt, Aug 26 '13 at 17:07

score 6 · Answer 1 · answered Aug 26 '13 at 17:02

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You could use GetSystemTime, which returns a SYSTEMTIME (with milliseconds).

answered Aug 26 '13 at 17:02

Reed Copsey

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score 1 · Answer 2 · answered Aug 26 '13 at 17:07

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GetTickCount gives you a one millisecond timer. It's perfect for timestamps since you don't need to convert anything. Even timespans can be calculated within a 49,6 days period.

answered Aug 26 '13 at 17:07

harper

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"The resolution of the GetTickCount function is limited to... the range of 10 milliseconds to 16 milliseconds. " – Mooing Duck Aug 26 '13 at 17:08
@MooingDuck: Definitely something to be aware of, because it affects a LOT of time functions. – Ben Voigt Aug 26 '13 at 17:11

timestamp in milliseconds in Windows

2 Answers2