QueryPerformanceFrequency

QueryPerformanceFrequency retrieves the frequency of the high-resolution performance counter, if one exists. The frequency cannot change while the system is running.

Syntax

BOOL QueryPerformanceFrequency(
    [out]    LARGE_INTEGER* lpFrequency
);

Parameters

[out] lpFrequency

Pointer to a variable that receives the current performance-counter frequency, in counts per second. This parameter can be zero if the installed hardware does not support a high-resolution performance counter.

Return Value

If the installed hardware supports a high-resolution performance counter, it returns a non-zero value. If the function fails, it returns 0 (zero).

For example, if the installed hardware does not support a high-resolution performance counter, the function fails.

To get extended error information, call GetLastError.

Remarks

The frequency of the high-resolution performance counter is not the processor speed.

Requirements

In Windows applications, this function is available by including RtApi.h and linking to RtApi.lib.

See Also:

• QueryPerformanceCounter