EngQueryPerformanceFrequency
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EngQueryPerformanceFrequency function

The EngQueryPerformanceFrequency function queries the frequency of the performance counter.

Syntax


VOID EngQueryPerformanceFrequency(
  _Out_ LONGLONG *pFrequency
);

Parameters

pFrequency [out]

Pointer to a location that receives the performance counter frequency.

Return value

None

Remarks

The resolution of the timer is 1/x, where x is the value returned in the location to which pFrequency points. For example, if the value returned in pFrequency is 2 million, each tick is 1/2 millionth of a second. Each 1/x millionth increment of the count corresponds to one second of elapsed time.

A driver should call this routine sparingly. Frequent calls to EngQueryPerformanceFrequency can degrade the I/O performance for the calling driver and for the system as a whole.

Requirements

Target platform

Universal

Version

Available in Windows 2000 and later versions of the Windows operating systems.

Header

Winddi.h (include Winddi.h)

Library

Win32k.lib

DLL

Win32k.sys

See also

EngQueryPerformanceCounter

 

 

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