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ExQueryTimerResolution routine

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

MaximumTime [out]

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.

MinimumTime [out]

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.

CurrentTime [out]

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

Version

Available starting with Windows 8.

Header

Wdm.h (include Wdm.h, Ntddk.h, or Ntifs.h)

IRQL

Any level.

See also

ExSetTimerResolution
KeSetTimerEx

 

 

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