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ExQueryTimerResolution function (wdm.h)

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The ExQueryTimerResolution routine reports the range of timer resolutions that are supported by the system clock.

Syntax

void ExQueryTimerResolution(
  [out] PULONG MaximumTime,
  [out] PULONG MinimumTime,
  [out] PULONG CurrentTime
);

Parameters

[out] MaximumTime

A pointer to a location to which the routine writes the maximum time interval, in 100-nanosecond units, between successive ticks of the system clock. A tick is an interrupt caused by the system clock timer.

[out] MinimumTime

A pointer to a location to which the routine writes the minimum time interval, in 100-nanosecond units, between successive ticks of the system clock.

[out] CurrentTime

A pointer to a location to which the routine writes the current time interval, in 100-nanosecond units, between successive ticks of the system clock.

Return value

None

Remarks

If your driver calls the ExSetTimerResolution routine to change the time interval between successive system clock interrupts, the driver can first call ExQueryTimerResolution to determine the range of intervals supported by the system clock.

When your driver calls a routine such as KeSetTimerEx to set a timer, the accuracy of the timer depends on the resolution of the system clock. For more information, see Timer Accuracy.

Requirements

Requirement Value
Minimum supported client Available starting with Windows 8.
Target Platform Universal
Header wdm.h (include Wdm.h, Ntddk.h, Ntifs.h)
Library Ntoskrnl.lib
IRQL Any level.

See also

ExSetTimerResolution

KeSetTimerEx