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windowsvisual-c++sleepgettickcount
Abhishek Jain
Abhishek Jain

Reputation: 10584

GetTickCount / Sleep not working? or is it a GetTickCount precision issue?

Checkout the below code:

tick1 = GetTickCount();
Sleep (100);
tick2 = GetTickCount ();

The tick2-tick1 most of times comes less than 100. My expectation is it should always 100+. Is my expectation wrong?

Upvotes: -1

Views: 675

Answers (1)

Vlad Feinstein
Vlad Feinstein

Reputation: 11311

Looks like yours (and mine) expectations ARE wrong.

I used better timing:

chrono::time_point<std::chrono::high_resolution_clock> tick1, tick2;
std::chrono::milliseconds timespan(100); // or whatever
for (int i = 0; i < 100; ++i)
{
    tick1 = chrono::high_resolution_clock::now();
    Sleep(100);
    tick2 = chrono::high_resolution_clock::now();
    std::chrono::duration<double> elapsed_seconds = tick2 - tick1;
    cout << elapsed_seconds.count() << endl;
}

The majority of intervals are 0.099XXX with 2 or 3 (out of 100) 0.1000XXX

The std::this_thread::sleep_for(...) recommended in Precise thread sleep needed. Max 1ms error has similar results. But the error is less than 1ms. Do you need better precision?

Upvotes: 0

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