Retrieves the actual output refresh period of a display as measured by the system time.


func CVDisplayLinkGetActualOutputVideoRefreshPeriod(_ displayLink: CVDisplayLink) -> Double



The display link to get the refresh period from.

Return Value

A double-precision floating-point value representing the actual refresh period in seconds. This value may be zero if the device is not running or is otherwise unavailable.


This call returns the actual output refresh period computed relative to the system time (as measured using the CVGetCurrentHostTime() function).

See Also

Inspecting Display Links

func CVDisplayLinkGetCurrentCGDisplay(CVDisplayLink) -> CGDirectDisplayID

Gets the current display associated with a display link.

func CVDisplayLinkGetCurrentTime(CVDisplayLink, UnsafeMutablePointer<CVTimeStamp>) -> CVReturn

Retrieves the current (“now”) time of a given display link.

func CVDisplayLinkTranslateTime(CVDisplayLink, UnsafePointer<CVTimeStamp>, UnsafeMutablePointer<CVTimeStamp>) -> CVReturn

Translates the time in the display link’s time base from one representation to another.

func CVDisplayLinkGetNominalOutputVideoRefreshPeriod(CVDisplayLink) -> CVTime

Retrieves the nominal refresh period of a display link.

func CVDisplayLinkGetOutputVideoLatency(CVDisplayLink) -> CVTime

Retrieves the nominal latency of a display link.

func CVDisplayLinkIsRunning(CVDisplayLink) -> Bool

Indicates whether a given display link is running.

func CVDisplayLinkGetTypeID() -> CFTypeID

Obtains the Core Foundation ID for the display link data type.