---
title: getPort
framework: corefoundation
role: symbol
role_heading: Instance Property
path: corefoundation/cfrunloopsourcecontext1/getport
---

# getPort

A callback to retrieve the native Mach port represented by the source. This callback is called when the source is either added to or removed from a run loop mode.

## Declaration

```swift
var getPort: ((UnsafeMutableRawPointer?) -> mach_port_t)!
```

## Parameters

- `info`: The info member of the doc://com.apple.corefoundation/documentation/CoreFoundation/CFRunLoopSourceContext1 structure that was used when creating the run loop source.

## Return Value

Return Value The native Mach port for the run loop source.

## Discussion

Discussion This callback is called whenever the run loop needs a source’s Mach port, which can happen in each iteration of the run loop’s loop. Because of the frequency with which the run loop may call this callback, make the function as efficient as possible. A version 1 run loop source must have a one-to-one relationship between itself and its Mach port. Each source must have only one Mach port associated with it and each Mach port must represent only one source.