---
title: "CMTimebaseSetTimerDispatchSourceToFireImmediately(_:timerSource:)"
framework: coremedia
role: symbol
role_heading: Function
path: "coremedia/cmtimebasesettimerdispatchsourcetofireimmediately(_:timersource:)"
---

# CMTimebaseSetTimerDispatchSourceToFireImmediately(_:timerSource:)

Sets the timer dispatch source to fire immediately once, overriding any previous timer call.

## Declaration

```swift
func CMTimebaseSetTimerDispatchSourceToFireImmediately(_ timebase: CMTimebase, timerSource: dispatch_source_t) -> OSStatus
```

## Discussion

Discussion The timer source you specify must be on the list of timers the timebase manages. This is equivalent to calling dispatch_source_set_timer(timerSource, DISPATCH_TIME_NOW, 0, 0 ); except that the timebase gets to know that it shouldn’t interfere.

## See Also

### Interacting with Timers

- [CMTimebaseAddTimer(_:timer:runloop:)](coremedia/cmtimebaseaddtimer(_:timer:runloop:).md)
- [CMTimebaseAddTimerDispatchSource(_:timerSource:)](coremedia/cmtimebaseaddtimerdispatchsource(_:timersource:).md)
- [CMTimebaseRemoveTimer(_:timer:)](coremedia/cmtimebaseremovetimer(_:timer:).md)
- [CMTimebaseRemoveTimerDispatchSource(_:timerSource:)](coremedia/cmtimebaseremovetimerdispatchsource(_:timersource:).md)
- [CMTimebaseSetTimerNextFireTime(_:timer:fireTime:flags:)](coremedia/cmtimebasesettimernextfiretime(_:timer:firetime:flags:).md)
- [CMTimebaseSetTimerToFireImmediately(_:timer:)](coremedia/cmtimebasesettimertofireimmediately(_:timer:).md)
- [CMTimebaseSetTimerDispatchSourceNextFireTime(_:timerSource:fireTime:flags:)](coremedia/cmtimebasesettimerdispatchsourcenextfiretime(_:timersource:firetime:flags:).md)