#ifndef _NTEXAPI_H
#if (PHNT_MODE != PHNT_MODE_KERNEL)

/**
 * The NtQueryTimerResolution routine retrieves the range and current value of the system interrupt timer.
 *
 * @param MaximumTime The maximum timer resolution, in 100-nanosecond units.
 * @param MinimumTime The minimum timer resolution, in 100-nanosecond units.
 * @param CurrentTime The current timer resolution, in 100-nanosecond units.
 * @return NTSTATUS Successful or errant status.
 */
NTSYSCALLAPI
NTSTATUS
NTAPI
NtQueryTimerResolution(
    _Out_ PULONG MaximumTime,
    _Out_ PULONG MinimumTime,
    _Out_ PULONG CurrentTime
    );

#endif
#endif
View code on GitHub

#ifndef _NTZWAPI_H

NTSYSCALLAPI
NTSTATUS
NTAPI
ZwQueryTimerResolution(
    _Out_ PULONG MaximumTime,
    _Out_ PULONG MinimumTime,
    _Out_ PULONG CurrentTime
    );

#endif
View code on GitHub

Function NtQueryTimerResolution returns resolution of system Timer in context of calling process. See also description of NtSetTimerResolution.

MinimumResolution

Means highest possible delay (in 100-ns units) between timer events.

MaximumResolution

Means lowest possible delay (in 100-ns units) between timer events.

CurrentResolution

Current timer resolution, in 100-ns units.

Documented by

Tomasz Nowak