NtGetTickCount - NtDoc

Native API online documentation, based on the System Informer (formerly Process Hacker) phnt headers

#ifndef _NTEXAPI_H
#if (PHNT_MODE != PHNT_MODE_KERNEL)

FORCEINLINE
ULONG
NtGetTickCount(
    VOID
    )
{
#ifdef _WIN64

    return (ULONG)((USER_SHARED_DATA->TickCountQuad * USER_SHARED_DATA->TickCountMultiplier) >> 24);

#else

    ULARGE_INTEGER tickCount;

    while (TRUE)
    {
        tickCount.HighPart = (ULONG)USER_SHARED_DATA->TickCount.High1Time;
        tickCount.LowPart = USER_SHARED_DATA->TickCount.LowPart;

        if (tickCount.HighPart == (ULONG)USER_SHARED_DATA->TickCount.High2Time)
            break;

        YieldProcessor();
    }

    return (ULONG)((UInt32x32To64(tickCount.LowPart, USER_SHARED_DATA->TickCountMultiplier) >> 24) +
        UInt32x32To64((tickCount.HighPart << 8) & 0xffffffff, USER_SHARED_DATA->TickCountMultiplier));

#endif
}

#endif
#endif
View code on GitHub

Function NtGetTickCount returns system Timer's ticks counter. This counter is also available in KUSER_SHARED_DATA structure as TickCountLow member.

Calling NtSetTimerResolution doesn't effect in counter's update resolution.

Documented by

Tomasz Nowak

Documented by

See also