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# CFMessagePortCreateRunLoopSource(_:_:_:)

Creates a CFRunLoopSource object for a CFMessagePort object.

```
func CFMessagePortCreateRunLoopSource(_ allocator: CFAllocator!, _ local: CFMessagePort!, _ order: CFIndex) -> CFRunLoopSource!
```

## Parameters

`allocator`

The allocator to use to allocate memory for the new object. Pass `NULL` or kCFAllocatorDefault to use the current default allocator.

`local`

The message port for which to create a run loop source.

`order`

A priority index indicating the order in which run loop sources are processed. `order` is currently ignored by CFMessagePort object run loop sources. Pass `0` for this value.

## Return Value

The new CFRunLoopSource object for `ms`. Ownership follows the [The Create Rule](https://developer.apple.com/library/archive/documentation/CoreFoundation/Conceptual/CFMemoryMgmt/Concepts/Ownership.html#//apple_ref/doc/uid/20001148-103029).

## Discussion

The run loop source is not automatically added to a run loop. To add the source to a run loop, use [`CFRunLoopAddSource(_:_:_:)`](/documentation/CoreFoundation/CFRunLoopAddSource(_:_:_:)).

### Special Considerations

This method is not available on iOS 7 and later—it will return `NULL` and log a sandbox violation in `syslog`. See [Concurrency Programming Guide](https://developer.apple.com/library/archive/documentation/General/Conceptual/ConcurrencyProgrammingGuide/Introduction/Introduction.html#//apple_ref/doc/uid/TP40008091) for possible replacement technologies.

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